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theory Parsing
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imports Base "Package/Simple_Inductive_Package"
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begin
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chapter {* Parsing *}
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text {*
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Isabelle distinguishes between \emph{outer} and \emph{inner} syntax.
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Theory commands, such as \isacommand{definition}, \isacommand{inductive} and so
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on, belong to the outer syntax, whereas items inside double quotation marks, such
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as terms, types and so on, belong to the inner syntax. For parsing inner syntax,
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Isabelle uses a rather general and sophisticated algorithm, which
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is driven by priority grammars. Parsers for outer syntax are built up by functional
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parsing combinators. These combinators are a well-established technique for parsing,
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which has, for example, been described in Paulson's classic ML-book \cite{paulson-ml2}.
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Isabelle developers are usually concerned with writing these outer syntax parsers,
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either for new definitional packages or for calling methods with specific arguments.
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\begin{readmore}
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The library
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for writing parser combinators is split up, roughly, into two parts.
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The first part consists of a collection of generic parser combinators defined
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in the structure @{ML_struct Scan} in the file
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@{ML_file "Pure/General/scan.ML"}. The second part of the library consists of
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combinators for dealing with specific token types, which are defined in the
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structure @{ML_struct OuterParse} in the file
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@{ML_file "Pure/Isar/outer_parse.ML"}.
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\end{readmore}
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*}
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section {* Building Generic Parsers *}
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text {*
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Let us first have a look at parsing strings using generic parsing combinators.
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The function @{ML "$$"} takes a string as argument and will ``consume'' this string from
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a given input list of strings. ``Consume'' in this context means that it will
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return a pair consisting of this string and the rest of the input list.
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For example:
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@{ML_response [display,gray] "($$ \"h\") (explode \"hello\")" "(\"h\", [\"e\", \"l\", \"l\", \"o\"])"}
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@{ML_response [display,gray] "($$ \"w\") (explode \"world\")" "(\"w\", [\"o\", \"r\", \"l\", \"d\"])"}
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The function @{ML "$$"} will either succeed (as in the two examples above) or raise the exception
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@{text "FAIL"} if no string can be consumed. For example trying to parse
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@{ML_response_fake [display,gray] "($$ \"x\") (explode \"world\")"
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"Exception FAIL raised"}
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will raise the exception @{text "FAIL"}.
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There are three exceptions used in the parsing combinators:
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\begin{itemize}
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\item @{text "FAIL"} is used to indicate that alternative routes of parsing
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might be explored.
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\item @{text "MORE"} indicates that there is not enough input for the parser. For example
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in @{text "($$ \"h\") []"}.
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\item @{text "ABORT"} is the exception that is raised when a dead end is reached.
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It is used for example in the function @{ML "!!"} (see below).
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\end{itemize}
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However, note that these exceptions are private to the parser and cannot be accessed
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by the programmer (for example to handle them).
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Slightly more general than the parser @{ML "$$"} is the function @{ML
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Scan.one}, in that it takes a predicate as argument and then parses exactly
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one item from the input list satisfying this predicate. For example the
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following parser either consumes an @{text [quotes] "h"} or a @{text
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[quotes] "w"}:
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@{ML_response [display,gray]
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"let
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val hw = Scan.one (fn x => x = \"h\" orelse x = \"w\")
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val input1 = (explode \"hello\")
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val input2 = (explode \"world\")
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in
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(hw input1, hw input2)
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end"
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"((\"h\", [\"e\", \"l\", \"l\", \"o\"]),(\"w\", [\"o\", \"r\", \"l\", \"d\"]))"}
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Two parser can be connected in sequence by using the function @{ML "--"}.
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For example parsing @{text "h"}, @{text "e"} and @{text "l"} in this
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sequence you can achieve by:
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@{ML_response [display,gray] "(($$ \"h\") -- ($$ \"e\") -- ($$ \"l\")) (explode \"hello\")"
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"(((\"h\", \"e\"), \"l\"), [\"l\", \"o\"])"}
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Note how the result of consumed strings builds up on the left as nested pairs.
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If, as in the previous example, you want to parse a particular string,
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then you should use the function @{ML Scan.this_string}:
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@{ML_response [display,gray] "Scan.this_string \"hell\" (explode \"hello\")"
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"(\"hell\", [\"o\"])"}
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Parsers that explore alternatives can be constructed using the function @{ML
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"||"}. For example, the parser @{ML "(p || q)" for p q} returns the
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result of @{text "p"}, in case it succeeds, otherwise it returns the
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result of @{text "q"}. For example:
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@{ML_response [display,gray]
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"let
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val hw = ($$ \"h\") || ($$ \"w\")
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val input1 = (explode \"hello\")
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val input2 = (explode \"world\")
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in
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(hw input1, hw input2)
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end"
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"((\"h\", [\"e\", \"l\", \"l\", \"o\"]), (\"w\", [\"o\", \"r\", \"l\", \"d\"]))"}
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The functions @{ML "|--"} and @{ML "--|"} work like the sequencing function
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for parsers, except that they discard the item being parsed by the first (respectively second)
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parser. For example:
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@{ML_response [display,gray]
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"let
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val just_e = ($$ \"h\") |-- ($$ \"e\")
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val just_h = ($$ \"h\") --| ($$ \"e\")
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val input = (explode \"hello\")
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in
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(just_e input, just_h input)
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end"
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"((\"e\", [\"l\", \"l\", \"o\"]),(\"h\", [\"l\", \"l\", \"o\"]))"}
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The parser @{ML "Scan.optional p x" for p x} returns the result of the parser
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@{text "p"}, if it succeeds; otherwise it returns
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the default value @{text "x"}. For example:
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@{ML_response [display,gray]
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"let
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val p = Scan.optional ($$ \"h\") \"x\"
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val input1 = (explode \"hello\")
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val input2 = (explode \"world\")
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in
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(p input1, p input2)
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end"
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"((\"h\", [\"e\", \"l\", \"l\", \"o\"]), (\"x\", [\"w\", \"o\", \"r\", \"l\", \"d\"]))"}
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The function @{ML Scan.option} works similarly, except no default value can
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be given. Instead, the result is wrapped as an @{text "option"}-type. For example:
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@{ML_response [display,gray]
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"let
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val p = Scan.option ($$ \"h\")
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val input1 = (explode \"hello\")
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val input2 = (explode \"world\")
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in
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(p input1, p input2)
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end" "((SOME \"h\", [\"e\", \"l\", \"l\", \"o\"]), (NONE, [\"w\", \"o\", \"r\", \"l\", \"d\"]))"}
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The function @{ML "!!"} helps to produce appropriate error messages
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during parsing. For example if you want to parse that @{text p} is immediately
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followed by @{text q}, or start a completely different parser @{text r},
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you might write:
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@{ML [display,gray] "(p -- q) || r" for p q r}
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However, this parser is problematic for producing an appropriate error
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message, in case the parsing of @{ML "(p -- q)" for p q} fails. Because in
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that case you lose the information that @{text p} should be followed by
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@{text q}. To see this consider the case in which @{text p} is present in
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the input, but not @{text q}. That means @{ML "(p -- q)" for p q} will fail
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and the alternative parser @{text r} will be tried. However in many
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circumstance this will be the wrong parser for the input ``p-followed-by-q''
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and therefore will also fail. The error message is then caused by the
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failure of @{text r}, not by the absence of @{text q} in the input. This
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kind of situation can be avoided when using the function @{ML "!!"}.
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This function aborts the whole process of parsing in case of a
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failure and prints an error message. For example if you invoke the parser
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@{ML [display,gray] "(!! (fn _ => \"foo\") ($$ \"h\"))"}
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on @{text [quotes] "hello"}, the parsing succeeds
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@{ML_response [display,gray]
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"(!! (fn _ => \"foo\") ($$ \"h\")) (explode \"hello\")"
+ − 184
"(\"h\", [\"e\", \"l\", \"l\", \"o\"])"}
+ − 185
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but if you invoke it on @{text [quotes] "world"}
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@{ML_response_fake [display,gray] "(!! (fn _ => \"foo\") ($$ \"h\")) (explode \"world\")"
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"Exception ABORT raised"}
40
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then the parsing aborts and the error message @{text "foo"} is printed. In order to
120
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see the error message properly, you need to prefix the parser with the function
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@{ML "Scan.error"}. For example:
40
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74
+ − 195
@{ML_response_fake [display,gray] "Scan.error (!! (fn _ => \"foo\") ($$ \"h\"))"
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"Exception Error \"foo\" raised"}
40
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+ − 198
This ``prefixing'' is usually done by wrappers such as @{ML "OuterSyntax.command"}
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(see Section~\ref{sec:newcommand} which explains this function in more detail).
40
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Let us now return to our example of parsing @{ML "(p -- q) || r" for p q
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r}. If you want to generate the correct error message for p-followed-by-q,
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then you have to write:
38
+ − 204
*}
+ − 205
69
+ − 206
ML{*fun p_followed_by_q p q r =
133
+ − 207
let
+ − 208
val err_msg = (fn _ => p ^ " is not followed by " ^ q)
+ − 209
in
+ − 210
($$ p -- (!! err_msg ($$ q))) || ($$ r -- $$ r)
+ − 211
end *}
38
+ − 212
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40
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text {*
65
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Running this parser with the @{text [quotes] "h"} and @{text [quotes] "e"}, and
+ − 216
the input @{text [quotes] "holle"}
40
+ − 217
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@{ML_response_fake [display,gray] "Scan.error (p_followed_by_q \"h\" \"e\" \"w\") (explode \"holle\")"
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"Exception ERROR \"h is not followed by e\" raised"}
40
+ − 220
65
+ − 221
produces the correct error message. Running it with
40
+ − 222
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@{ML_response [display,gray] "Scan.error (p_followed_by_q \"h\" \"e\" \"w\") (explode \"wworld\")"
40
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"((\"w\", \"w\"), [\"o\", \"r\", \"l\", \"d\"])"}
+ − 225
+ − 226
yields the expected parsing.
38
+ − 227
58
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The function @{ML "Scan.repeat p" for p} will apply a parser @{text p} as
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often as it succeeds. For example:
40
+ − 230
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@{ML_response [display,gray] "Scan.repeat ($$ \"h\") (explode \"hhhhello\")"
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"([\"h\", \"h\", \"h\", \"h\"], [\"e\", \"l\", \"l\", \"o\"])"}
+ − 233
+ − 234
Note that @{ML "Scan.repeat"} stores the parsed items in a list. The function
58
+ − 235
@{ML "Scan.repeat1"} is similar, but requires that the parser @{text "p"}
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succeeds at least once.
48
+ − 237
58
+ − 238
Also note that the parser would have aborted with the exception @{text MORE}, if
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you had run it only on just @{text [quotes] "hhhh"}. This can be avoided by using
49
+ − 240
the wrapper @{ML Scan.finite} and the ``stopper-token'' @{ML Symbol.stopper}. With
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+ − 241
them you can write:
49
+ − 242
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@{ML_response [display,gray] "Scan.finite Symbol.stopper (Scan.repeat ($$ \"h\")) (explode \"hhhh\")"
49
+ − 244
"([\"h\", \"h\", \"h\", \"h\"], [])"}
+ − 245
65
+ − 246
@{ML Symbol.stopper} is the ``end-of-input'' indicator for parsing strings;
128
+ − 247
other stoppers need to be used when parsing, for example, tokens. However, this kind of
65
+ − 248
manually wrapping is often already done by the surrounding infrastructure.
49
+ − 249
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The function @{ML Scan.repeat} can be used with @{ML Scan.one} to read any
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+ − 251
string as in
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+ − 252
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@{ML_response [display,gray]
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"let
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val p = Scan.repeat (Scan.one Symbol.not_eof)
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val input = (explode \"foo bar foo\")
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in
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Scan.finite Symbol.stopper p input
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+ − 259
end"
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"([\"f\", \"o\", \"o\", \" \", \"b\", \"a\", \"r\", \" \", \"f\", \"o\", \"o\"], [])"}
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+ − 261
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where the function @{ML Symbol.not_eof} ensures that we do not read beyond the
65
+ − 263
end of the input string (i.e.~stopper symbol).
56
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diff
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+ − 264
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The function @{ML "Scan.unless p q" for p q} takes two parsers: if the first one can
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+ − 266
parse the input, then the whole parser fails; if not, then the second is tried. Therefore
56
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diff
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+ − 267
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@{ML_response_fake_both [display,gray] "Scan.unless ($$ \"h\") ($$ \"w\") (explode \"hello\")"
56
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+ − 269
"Exception FAIL raised"}
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diff
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+ − 270
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+ − 271
fails, while
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+ − 272
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@{ML_response [display,gray] "Scan.unless ($$ \"h\") ($$ \"w\") (explode \"world\")"
56
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+ − 274
"(\"w\",[\"o\", \"r\", \"l\", \"d\"])"}
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diff
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+ − 275
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diff
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+ − 276
succeeds.
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diff
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+ − 277
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+ − 278
The functions @{ML Scan.repeat} and @{ML Scan.unless} can be combined to read any
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diff
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+ − 279
input until a certain marker symbol is reached. In the example below the marker
60
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+ − 280
symbol is a @{text [quotes] "*"}.
56
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diff
changeset
+ − 281
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@{ML_response [display,gray]
56
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diff
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+ − 283
"let
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diff
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+ − 284
val p = Scan.repeat (Scan.unless ($$ \"*\") (Scan.one Symbol.not_eof))
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+ − 285
val input1 = (explode \"fooooo\")
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diff
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+ − 286
val input2 = (explode \"foo*ooo\")
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diff
changeset
+ − 287
in
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diff
changeset
+ − 288
(Scan.finite Symbol.stopper p input1,
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diff
changeset
+ − 289
Scan.finite Symbol.stopper p input2)
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diff
changeset
+ − 290
end"
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diff
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+ − 291
"(([\"f\", \"o\", \"o\", \"o\", \"o\", \"o\"], []),
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diff
changeset
+ − 292
([\"f\", \"o\", \"o\"], [\"*\", \"o\", \"o\", \"o\"]))"}
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diff
changeset
+ − 293
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diff
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+ − 294
After parsing is done, you nearly always want to apply a function on the parsed
104
+ − 295
items. One way to do this is the function @{ML "(p >> f)" for p f}, which runs
58
+ − 296
first the parser @{text p} and upon successful completion applies the
+ − 297
function @{text f} to the result. For example
38
+ − 298
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+ − 299
@{ML_response [display,gray]
40
+ − 300
"let
193
+ − 301
fun double (x, y) = (x ^ x, y ^ y)
40
+ − 302
in
+ − 303
(($$ \"h\") -- ($$ \"e\") >> double) (explode \"hello\")
+ − 304
end"
+ − 305
"((\"hh\", \"ee\"), [\"l\", \"l\", \"o\"])"}
+ − 306
104
+ − 307
doubles the two parsed input strings; or
59
+ − 308
72
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diff
changeset
+ − 309
@{ML_response [display,gray]
59
+ − 310
"let
104
+ − 311
val p = Scan.repeat (Scan.one Symbol.not_eof)
59
+ − 312
val input = (explode \"foo bar foo\")
+ − 313
in
104
+ − 314
Scan.finite Symbol.stopper (p >> implode) input
59
+ − 315
end"
+ − 316
"(\"foo bar foo\",[])"}
+ − 317
60
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diff
changeset
+ − 318
where the single-character strings in the parsed output are transformed
59
+ − 319
back into one string.
41
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diff
changeset
+ − 320
193
+ − 321
(FIXME: move to an earlier place)
+ − 322
125
+ − 323
The function @{ML Scan.ahead} parses some input, but leaves the original
+ − 324
input unchanged. For example:
+ − 325
+ − 326
@{ML_response [display,gray]
+ − 327
"Scan.ahead (Scan.this_string \"foo\") (explode \"foo\")"
+ − 328
"(\"foo\", [\"f\", \"o\", \"o\"])"}
56
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diff
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+ − 329
40
+ − 330
The function @{ML Scan.lift} takes a parser and a pair as arguments. This function applies
+ − 331
the given parser to the second component of the pair and leaves the first component
+ − 332
untouched. For example
38
+ − 333
72
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diff
changeset
+ − 334
@{ML_response [display,gray]
40
+ − 335
"Scan.lift (($$ \"h\") -- ($$ \"e\")) (1,(explode \"hello\"))"
+ − 336
"((\"h\", \"e\"), (1, [\"l\", \"l\", \"o\"]))"}
+ − 337
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diff
changeset
+ − 338
(FIXME: In which situations is this useful? Give examples.)
149
+ − 339
+ − 340
\begin{exercise}\label{ex:scancmts}
+ − 341
Write a parser that parses an input string so that any comment enclosed
+ − 342
inside @{text "(*\<dots>*)"} is replaced by a the same comment but enclosed inside
+ − 343
@{text "(**\<dots>**)"} in the output string. To enclose a string, you can use the
+ − 344
function @{ML "enclose s1 s2 s" for s1 s2 s} which produces the string @{ML
+ − 345
"s1 ^ s ^ s2" for s1 s2 s}.
+ − 346
\end{exercise}
40
+ − 347
*}
+ − 348
41
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diff
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+ − 349
section {* Parsing Theory Syntax *}
38
+ − 350
40
+ − 351
text {*
188
+ − 352
(FIXME: context parser)
+ − 353
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+ − 354
Most of the time, however, Isabelle developers have to deal with parsing
156
+ − 355
tokens, not strings. These token parsers have the type:
128
+ − 356
*}
+ − 357
+ − 358
ML{*type 'a parser = OuterLex.token list -> 'a * OuterLex.token list*}
+ − 359
+ − 360
text {*
149
+ − 361
The reason for using token parsers is that theory syntax, as well as the
128
+ − 362
parsers for the arguments of proof methods, use the type @{ML_type
+ − 363
OuterLex.token} (which is identical to the type @{ML_type
+ − 364
OuterParse.token}). However, there are also handy parsers for
+ − 365
ML-expressions and ML-files.
42
+ − 366
+ − 367
\begin{readmore}
40
+ − 368
The parser functions for the theory syntax are contained in the structure
42
+ − 369
@{ML_struct OuterParse} defined in the file @{ML_file "Pure/Isar/outer_parse.ML"}.
+ − 370
The definition for tokens is in the file @{ML_file "Pure/Isar/outer_lex.ML"}.
+ − 371
\end{readmore}
44
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diff
changeset
+ − 372
75
+ − 373
The structure @{ML_struct OuterLex} defines several kinds of tokens (for example
53
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diff
changeset
+ − 374
@{ML "Ident" in OuterLex} for identifiers, @{ML "Keyword" in OuterLex} for keywords and
0c3580c831a4
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diff
changeset
+ − 375
@{ML "Command" in OuterLex} for commands). Some token parsers take into account the
75
+ − 376
kind of tokens.
53
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diff
changeset
+ − 377
*}
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diff
changeset
+ − 378
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diff
changeset
+ − 379
text {*
104
+ − 380
The first example shows how to generate a token list out of a string using
128
+ − 381
the function @{ML "OuterSyntax.scan"}. It is given the argument @{ML "Position.none"}
+ − 382
since, at the moment, we are not interested in generating
102
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diff
changeset
+ − 383
precise error messages. The following code
44
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diff
changeset
+ − 384
72
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diff
changeset
+ − 385
@{ML_response_fake [display,gray] "OuterSyntax.scan Position.none \"hello world\""
50
+ − 386
"[Token (\<dots>,(Ident, \"hello\"),\<dots>),
+ − 387
Token (\<dots>,(Space, \" \"),\<dots>),
+ − 388
Token (\<dots>,(Ident, \"world\"),\<dots>)]"}
+ − 389
+ − 390
produces three tokens where the first and the last are identifiers, since
58
+ − 391
@{text [quotes] "hello"} and @{text [quotes] "world"} do not match any
50
+ − 392
other syntactic category.\footnote{Note that because of a possible a bug in
102
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diff
changeset
+ − 393
the PolyML runtime system the result is printed as @{text [quotes] "?"}, instead of
75
+ − 394
the tokens.} The second indicates a space.
50
+ − 395
+ − 396
Many parsing functions later on will require spaces, comments and the like
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 397
to have already been filtered out. So from now on we are going to use the
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 398
functions @{ML filter} and @{ML OuterLex.is_proper} do this. For example:
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 399
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 400
@{ML_response_fake [display,gray]
50
+ − 401
"let
+ − 402
val input = OuterSyntax.scan Position.none \"hello world\"
+ − 403
in
+ − 404
filter OuterLex.is_proper input
+ − 405
end"
+ − 406
"[Token (\<dots>,(Ident, \"hello\"), \<dots>), Token (\<dots>,(Ident, \"world\"), \<dots>)]"}
+ − 407
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 408
For convenience we define the function:
50
+ − 409
+ − 410
*}
+ − 411
69
+ − 412
ML{*fun filtered_input str =
160
cc9359bfacf4
redefined the functions warning and tracing in order to properly match more antiquotations
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 413
filter OuterLex.is_proper (OuterSyntax.scan Position.none str) *}
50
+ − 414
+ − 415
text {*
+ − 416
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 417
If you now parse
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 418
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 419
@{ML_response_fake [display,gray]
50
+ − 420
"filtered_input \"inductive | for\""
+ − 421
"[Token (\<dots>,(Command, \"inductive\"),\<dots>),
+ − 422
Token (\<dots>,(Keyword, \"|\"),\<dots>),
+ − 423
Token (\<dots>,(Keyword, \"for\"),\<dots>)]"}
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 424
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 425
you obtain a list consisting of only a command and two keyword tokens.
104
+ − 426
If you want to see which keywords and commands are currently known to Isabelle, type in
75
+ − 427
the following code (you might have to adjust the @{ML print_depth} in order to
47
4daf913fdbe1
hakked latex so that it does not display ML {* *}; general tuning
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 428
see the complete list):
4daf913fdbe1
hakked latex so that it does not display ML {* *}; general tuning
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 429
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 430
@{ML_response_fake [display,gray]
47
4daf913fdbe1
hakked latex so that it does not display ML {* *}; general tuning
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 431
"let
4daf913fdbe1
hakked latex so that it does not display ML {* *}; general tuning
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 432
val (keywords, commands) = OuterKeyword.get_lexicons ()
4daf913fdbe1
hakked latex so that it does not display ML {* *}; general tuning
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 433
in
4daf913fdbe1
hakked latex so that it does not display ML {* *}; general tuning
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 434
(Scan.dest_lexicon commands, Scan.dest_lexicon keywords)
4daf913fdbe1
hakked latex so that it does not display ML {* *}; general tuning
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 435
end"
132
+ − 436
"([\"}\", \"{\", \<dots>], [\"\<rightleftharpoons>\", \"\<leftharpoondown>\", \<dots>])"}
42
+ − 437
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 438
The parser @{ML "OuterParse.$$$"} parses a single keyword. For example:
50
+ − 439
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 440
@{ML_response [display,gray]
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 441
"let
50
+ − 442
val input1 = filtered_input \"where for\"
+ − 443
val input2 = filtered_input \"| in\"
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 444
in
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 445
(OuterParse.$$$ \"where\" input1, OuterParse.$$$ \"|\" input2)
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 446
end"
128
+ − 447
"((\"where\",\<dots>), (\"|\",\<dots>))"}
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 448
108
8bea3f74889d
added to the tactical chapter; polished; added the tabularstar environment (which is just tabular*)
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 449
Like before, you can sequentially connect parsers with @{ML "--"}. For example:
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 450
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 451
@{ML_response [display,gray]
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 452
"let
50
+ − 453
val input = filtered_input \"| in\"
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 454
in
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 455
(OuterParse.$$$ \"|\" -- OuterParse.$$$ \"in\") input
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 456
end"
183
+ − 457
"((\"|\", \"in\"), [])"}
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 458
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 459
The parser @{ML "OuterParse.enum s p" for s p} parses a possibly empty
58
+ − 460
list of items recognised by the parser @{text p}, where the items being parsed
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 461
are separated by the string @{text s}. For example:
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 462
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 463
@{ML_response [display,gray]
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 464
"let
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 465
val input = filtered_input \"in | in | in foo\"
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 466
in
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 467
(OuterParse.enum \"|\" (OuterParse.$$$ \"in\")) input
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 468
end"
183
+ − 469
"([\"in\", \"in\", \"in\"], [\<dots>])"}
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 470
50
+ − 471
@{ML "OuterParse.enum1"} works similarly, except that the parsed list must
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 472
be non-empty. Note that we had to add a string @{text [quotes] "foo"} at the
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 473
end of the parsed string, otherwise the parser would have consumed all
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 474
tokens and then failed with the exception @{text "MORE"}. Like in the
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 475
previous section, we can avoid this exception using the wrapper @{ML
50
+ − 476
Scan.finite}. This time, however, we have to use the ``stopper-token'' @{ML
102
5e309df58557
general cleaning up; deleted antiquotation ML_text; adjusted pathnames of various files in the distribution
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 477
OuterLex.stopper}. We can write:
49
+ − 478
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 479
@{ML_response [display,gray]
49
+ − 480
"let
50
+ − 481
val input = filtered_input \"in | in | in\"
49
+ − 482
in
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 483
Scan.finite OuterLex.stopper
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 484
(OuterParse.enum \"|\" (OuterParse.$$$ \"in\")) input
49
+ − 485
end"
183
+ − 486
"([\"in\", \"in\", \"in\"], [])"}
49
+ − 487
75
+ − 488
The following function will help to run examples.
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 489
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 490
*}
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 491
69
+ − 492
ML{*fun parse p input = Scan.finite OuterLex.stopper (Scan.error p) input *}
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 493
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 494
text {*
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 495
49
+ − 496
The function @{ML "OuterParse.!!!"} can be used to force termination of the
193
+ − 497
parser in case of a dead end, just like @{ML "Scan.!!"} (see previous section).
+ − 498
Except that the error message of @{ML "OuterParse.!!!"} is fixed to be
+ − 499
@{text [quotes] "Outer syntax error"}
49
+ − 500
with a relatively precise description of the failure. For example:
+ − 501
72
7b8c4fe235aa
added an antiquotation option [gray] for gray boxes around displays
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 502
@{ML_response_fake [display,gray]
49
+ − 503
"let
50
+ − 504
val input = filtered_input \"in |\"
49
+ − 505
val parse_bar_then_in = OuterParse.$$$ \"|\" -- OuterParse.$$$ \"in\"
+ − 506
in
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 507
parse (OuterParse.!!! parse_bar_then_in) input
49
+ − 508
end"
+ − 509
"Exception ERROR \"Outer syntax error: keyword \"|\" expected,
+ − 510
but keyword in was found\" raised"
+ − 511
}
42
+ − 512
65
+ − 513
\begin{exercise} (FIXME)
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 514
A type-identifier, for example @{typ "'a"}, is a token of
54
+ − 515
kind @{ML "Keyword" in OuterLex}. It can be parsed using
+ − 516
the function @{ML OuterParse.type_ident}.
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 517
\end{exercise}
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 518
104
+ − 519
(FIXME: or give parser for numbers)
53
0c3580c831a4
removed the @{ML ...} antiquotation in favour of @{ML_open ...x}
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 520
125
+ − 521
Whenever there is a possibility that the processing of user input can fail,
+ − 522
it is a good idea to give as much information about where the error
+ − 523
occured. For this Isabelle can attach positional information to tokens
+ − 524
and then thread this information up the processing chain. To see this,
128
+ − 525
modify the function @{ML filtered_input} described earlier to
41
b11653b11bd3
further progress on the parsing section and tuning on the antiqu's
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 526
*}
b11653b11bd3
further progress on the parsing section and tuning on the antiqu's
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 527
125
+ − 528
ML{*fun filtered_input' str =
+ − 529
filter OuterLex.is_proper (OuterSyntax.scan (Position.line 7) str) *}
49
+ − 530
+ − 531
text {*
125
+ − 532
where we pretend the parsed string starts on line 7. An example is
49
+ − 533
125
+ − 534
@{ML_response_fake [display,gray]
+ − 535
"filtered_input' \"foo \\n bar\""
+ − 536
"[Token ((\"foo\", ({line=7, end_line=7}, {line=7})), (Ident, \"foo\"), \<dots>),
+ − 537
Token ((\"bar\", ({line=8, end_line=8}, {line=8})), (Ident, \"bar\"), \<dots>)]"}
+ − 538
+ − 539
in which the @{text [quotes] "\\n"} causes the second token to be in
+ − 540
line 8.
+ − 541
126
+ − 542
By using the parser @{ML OuterParse.position} you can decode the positional
125
+ − 543
information and return it as part of the parsed input. For example
+ − 544
+ − 545
@{ML_response_fake [display,gray]
+ − 546
"let
+ − 547
val input = (filtered_input' \"where\")
+ − 548
in
+ − 549
parse (OuterParse.position (OuterParse.$$$ \"where\")) input
+ − 550
end"
+ − 551
"((\"where\", {line=7, end_line=7}), [])"}
+ − 552
+ − 553
\begin{readmore}
+ − 554
The functions related to positions are implemented in the file
+ − 555
@{ML_file "Pure/General/position.ML"}.
+ − 556
\end{readmore}
49
+ − 557
+ − 558
*}
+ − 559
193
+ − 560
section {* Context Parser (TBD) *}
+ − 561
+ − 562
text {*
+ − 563
Used for example in \isacommand{attribute\_setup} and \isacommand{method\_setup}.
+ − 564
*}
+ − 565
207
+ − 566
section {* Argument and Attribute Parsers (TBD) *}
+ − 567
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 568
section {* Parsing Inner Syntax *}
42
+ − 569
125
+ − 570
text {*
+ − 571
There is usually no need to write your own parser for parsing inner syntax, that is
+ − 572
for terms and types: you can just call the pre-defined parsers. Terms can
+ − 573
be parsed using the function @{ML OuterParse.term}. For example:
+ − 574
+ − 575
@{ML_response [display,gray]
+ − 576
"let
+ − 577
val input = OuterSyntax.scan Position.none \"foo\"
44
dee4b3e66dfe
added a readme chapter for prospective authors; added commands for referring to the Isar Reference Manual
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 578
in
125
+ − 579
OuterParse.term input
+ − 580
end"
+ − 581
"(\"\\^E\\^Ftoken\\^Efoo\\^E\\^F\\^E\", [])"}
+ − 582
+ − 583
The function @{ML OuterParse.prop} is similar, except that it gives a different
127
+ − 584
error message, when parsing fails. As you can see, the parser not just returns
+ − 585
the parsed string, but also some encoded information. You can decode the
+ − 586
information with the function @{ML YXML.parse}. For example
+ − 587
+ − 588
@{ML_response [display,gray]
+ − 589
"YXML.parse \"\\^E\\^Ftoken\\^Efoo\\^E\\^F\\^E\""
+ − 590
"XML.Elem (\"token\", [], [XML.Text \"foo\"])"}
+ − 591
149
+ − 592
The result of the decoding is an XML-tree. You can see better what is going on if
131
+ − 593
you replace @{ML Position.none} by @{ML "Position.line 42"}, say:
101
+ − 594
125
+ − 595
@{ML_response [display,gray]
+ − 596
"let
+ − 597
val input = OuterSyntax.scan (Position.line 42) \"foo\"
+ − 598
in
127
+ − 599
YXML.parse (fst (OuterParse.term input))
125
+ − 600
end"
127
+ − 601
"XML.Elem (\"token\", [(\"line\", \"42\"), (\"end_line\", \"42\")], [XML.Text \"foo\"])"}
125
+ − 602
149
+ − 603
The positional information is stored as part of an XML-tree so that code
+ − 604
called later on will be able to give more precise error messages.
125
+ − 605
127
+ − 606
\begin{readmore}
128
+ − 607
The functions to do with input and output of XML and YXML are defined
127
+ − 608
in @{ML_file "Pure/General/xml.ML"} and @{ML_file "Pure/General/yxml.ML"}.
+ − 609
\end{readmore}
160
cc9359bfacf4
redefined the functions warning and tracing in order to properly match more antiquotations
Christian Urban <urbanc@in.tum.de>
diff
changeset
+ − 610
125
+ − 611
*}
101
+ − 612
116
+ − 613
section {* Parsing Specifications\label{sec:parsingspecs} *}
101
+ − 614
+ − 615
text {*
121
+ − 616
There are a number of special purpose parsers that help with parsing
156
+ − 617
specifications of function definitions, inductive predicates and so on. In
121
+ − 618
Capter~\ref{chp:package}, for example, we will need to parse specifications
+ − 619
for inductive predicates of the form:
+ − 620
*}
101
+ − 621
121
+ − 622
simple_inductive
+ − 623
even and odd
+ − 624
where
+ − 625
even0: "even 0"
+ − 626
| evenS: "odd n \<Longrightarrow> even (Suc n)"
+ − 627
| oddS: "even n \<Longrightarrow> odd (Suc n)"
101
+ − 628
+ − 629
text {*
121
+ − 630
For this we are going to use the parser:
101
+ − 631
*}
+ − 632
121
+ − 633
ML %linenosgray{*val spec_parser =
126
+ − 634
OuterParse.fixes --
+ − 635
Scan.optional
+ − 636
(OuterParse.$$$ "where" |--
+ − 637
OuterParse.!!!
+ − 638
(OuterParse.enum1 "|"
+ − 639
(SpecParse.opt_thm_name ":" -- OuterParse.prop))) []*}
120
+ − 640
101
+ − 641
text {*
126
+ − 642
Note that the parser does not parse the keyword \simpleinductive, even if it is
+ − 643
meant to process definitions as shown above. The parser of the keyword
128
+ − 644
will be given by the infrastructure that will eventually call @{ML spec_parser}.
126
+ − 645
+ − 646
124
+ − 647
To see what the parser returns, let us parse the string corresponding to the
121
+ − 648
definition of @{term even} and @{term odd}:
+ − 649
101
+ − 650
@{ML_response [display,gray]
+ − 651
"let
+ − 652
val input = filtered_input
+ − 653
(\"even and odd \" ^
+ − 654
\"where \" ^
+ − 655
\" even0[intro]: \\\"even 0\\\" \" ^
+ − 656
\"| evenS[intro]: \\\"odd n \<Longrightarrow> even (Suc n)\\\" \" ^
+ − 657
\"| oddS[intro]: \\\"even n \<Longrightarrow> odd (Suc n)\\\"\")
+ − 658
in
120
+ − 659
parse spec_parser input
101
+ − 660
end"
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+ − 661
"(([(even, NONE, NoSyn), (odd, NONE, NoSyn)],
101
+ − 662
[((even0,\<dots>), \"\\^E\\^Ftoken\\^Eeven 0\\^E\\^F\\^E\"),
+ − 663
((evenS,\<dots>), \"\\^E\\^Ftoken\\^Eodd n \<Longrightarrow> even (Suc n)\\^E\\^F\\^E\"),
+ − 664
((oddS,\<dots>), \"\\^E\\^Ftoken\\^Eeven n \<Longrightarrow> odd (Suc n)\\^E\\^F\\^E\")]), [])"}
121
+ − 665
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changeset
+ − 666
As you see, the result is a pair consisting of a list of
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changeset
+ − 667
variables with optional type-annotation and syntax-annotation, and a list of
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diff
changeset
+ − 668
rules where every rule has optionally a name and an attribute.
121
+ − 669
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changeset
+ − 670
The function @{ML OuterParse.fixes} in Line 2 of the parser reads an
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changeset
+ − 671
\isacommand{and}-separated
124
+ − 672
list of variables that can include optional type annotations and syntax translations.
121
+ − 673
For example:\footnote{Note that in the code we need to write
+ − 674
@{text "\\\"int \<Rightarrow> bool\\\""} in order to properly escape the double quotes
+ − 675
in the compound type.}
+ − 676
+ − 677
@{ML_response [display,gray]
+ − 678
"let
+ − 679
val input = filtered_input
+ − 680
\"foo::\\\"int \<Rightarrow> bool\\\" and bar::nat (\\\"BAR\\\" 100) and blonk\"
+ − 681
in
+ − 682
parse OuterParse.fixes input
+ − 683
end"
+ − 684
"([(foo, SOME \"\\^E\\^Ftoken\\^Eint \<Rightarrow> bool\\^E\\^F\\^E\", NoSyn),
+ − 685
(bar, SOME \"\\^E\\^Ftoken\\^Enat\\^E\\^F\\^E\", Mixfix (\"BAR\", [], 100)),
+ − 686
(blonk, NONE, NoSyn)],[])"}
50
+ − 687
*}
+ − 688
121
+ − 689
text {*
156
+ − 690
Whenever types are given, they are stored in the @{ML SOME}s. The types are
+ − 691
not yet used to type the variables: this must be done by type-inference later
149
+ − 692
on. Since types are part of the inner syntax they are strings with some
+ − 693
encoded information (see previous section). If a syntax translation is
+ − 694
present for a variable, then it is stored in the @{ML Mixfix} datastructure;
+ − 695
no syntax translation is indicated by @{ML NoSyn}.
121
+ − 696
+ − 697
\begin{readmore}
+ − 698
The datastructre for sytax annotations is defined in @{ML_file "Pure/Syntax/mixfix.ML"}.
+ − 699
\end{readmore}
+ − 700
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+ − 701
Lines 3 to 7 in the function @{ML spec_parser} implement the parser for a
131
+ − 702
list of introduction rules, that is propositions with theorem
+ − 703
annotations. The introduction rules are propositions parsed by @{ML
+ − 704
OuterParse.prop}. However, they can include an optional theorem name plus
121
+ − 705
some attributes. For example
+ − 706
+ − 707
@{ML_response [display,gray] "let
+ − 708
val input = filtered_input \"foo_lemma[intro,dest!]:\"
+ − 709
val ((name, attrib), _) = parse (SpecParse.thm_name \":\") input
+ − 710
in
+ − 711
(name, map Args.dest_src attrib)
+ − 712
end" "(foo_lemma, [((\"intro\", []), \<dots>), ((\"dest\", [\<dots>]), \<dots>)])"}
+ − 713
+ − 714
The function @{ML opt_thm_name in SpecParse} is the ``optional'' variant of
131
+ − 715
@{ML thm_name in SpecParse}. Theorem names can contain attributes. The name
+ − 716
has to end with @{text [quotes] ":"}---see the argument of
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+ − 717
the function @{ML SpecParse.opt_thm_name} in Line 7.
121
+ − 718
+ − 719
\begin{readmore}
+ − 720
Attributes and arguments are implemented in the files @{ML_file "Pure/Isar/attrib.ML"}
+ − 721
and @{ML_file "Pure/Isar/args.ML"}.
+ − 722
\end{readmore}
101
+ − 723
*}
65
+ − 724
193
+ − 725
text_raw {*
+ − 726
\begin{exercise}
207
+ − 727
Have a look at how the parser @{ML SpecParse.where_alt_specs} is implemented
+ − 728
in file @{ML_file "Pure/Isar/spec_parse.ML"}. This parser corresponds
+ − 729
to the ``where-part'' of the introduction rules given above. Below
+ − 730
we paraphrase the code of @{ML SpecParse.where_alt_specs} adapted to our
+ − 731
purposes.
193
+ − 732
\begin{isabelle}
+ − 733
*}
+ − 734
ML %linenosgray{*val spec_parser' =
+ − 735
OuterParse.fixes --
+ − 736
Scan.optional
+ − 737
(OuterParse.$$$ "where" |--
+ − 738
OuterParse.!!!
+ − 739
(OuterParse.enum1 "|"
+ − 740
((SpecParse.opt_thm_name ":" -- OuterParse.prop) --|
+ − 741
Scan.option (Scan.ahead (OuterParse.name ||
+ − 742
OuterParse.$$$ "[") --
+ − 743
OuterParse.!!! (OuterParse.$$$ "|"))))) [] *}
+ − 744
text_raw {*
+ − 745
\end{isabelle}
207
+ − 746
Both parsers accept the same input, but if you look closely, you can notice
+ − 747
an additional ``tail'' (Lines 8 to 10) in @{ML spec_parser'}. What is the purpose of
+ − 748
this additional ``tail''?
193
+ − 749
\end{exercise}
+ − 750
*}
+ − 751
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+ − 752
section {* New Commands and Keyword Files\label{sec:newcommand} *}
65
+ − 753
+ − 754
text {*
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+ − 755
(FIXME: update to the right command setup --- is this still needed?)
188
+ − 756
68
+ − 757
Often new commands, for example for providing new definitional principles,
+ − 758
need to be implemented. While this is not difficult on the ML-level,
66
+ − 759
new commands, in order to be useful, need to be recognised by
65
+ − 760
ProofGeneral. This results in some subtle configuration issues, which we
+ − 761
will explain in this section.
+ − 762
74
+ − 763
To keep things simple, let us start with a ``silly'' command that does nothing
+ − 764
at all. We shall name this command \isacommand{foobar}. On the ML-level it can be
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+ − 765
defined as:
68
+ − 766
*}
65
+ − 767
69
+ − 768
ML{*let
68
+ − 769
val do_nothing = Scan.succeed (Toplevel.theory I)
+ − 770
val kind = OuterKeyword.thy_decl
65
+ − 771
in
68
+ − 772
OuterSyntax.command "foobar" "description of foobar" kind do_nothing
69
+ − 773
end *}
65
+ − 774
68
+ − 775
text {*
74
+ − 776
The crucial function @{ML OuterSyntax.command} expects a name for the command, a
68
+ − 777
short description, a kind indicator (which we will explain later on more thoroughly) and a
74
+ − 778
parser producing a top-level transition function (its purpose will also explained
66
+ − 779
later).
65
+ − 780
101
+ − 781
While this is everything you have to do on the ML-level, you need a keyword
68
+ − 782
file that can be loaded by ProofGeneral. This is to enable ProofGeneral to
+ − 783
recognise \isacommand{foobar} as a command. Such a keyword file can be
74
+ − 784
generated with the command-line:
68
+ − 785
74
+ − 786
@{text [display] "$ isabelle keywords -k foobar some_log_files"}
65
+ − 787
74
+ − 788
The option @{text "-k foobar"} indicates which postfix the name of the keyword file
80
+ − 789
will be assigned. In the case above the file will be named @{text
86
+ − 790
"isar-keywords-foobar.el"}. This command requires log files to be
68
+ − 791
present (in order to extract the keywords from them). To generate these log
101
+ − 792
files, you first need to package the code above into a separate theory file named
68
+ − 793
@{text "Command.thy"}, say---see Figure~\ref{fig:commandtheory} for the
+ − 794
complete code.
65
+ − 795
66
+ − 796
+ − 797
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+ − 798
\begin{figure}[t]
69
+ − 799
\begin{graybox}\small
66
+ − 800
\isacommand{theory}~@{text Command}\\
+ − 801
\isacommand{imports}~@{text Main}\\
+ − 802
\isacommand{begin}\\
85
+ − 803
\isacommand{ML}~@{text "\<verbopen>"}\\
66
+ − 804
@{ML
+ − 805
"let
68
+ − 806
val do_nothing = Scan.succeed (Toplevel.theory I)
+ − 807
val kind = OuterKeyword.thy_decl
66
+ − 808
in
68
+ − 809
OuterSyntax.command \"foobar\" \"description of foobar\" kind do_nothing
66
+ − 810
end"}\\
85
+ − 811
@{text "\<verbclose>"}\\
66
+ − 812
\isacommand{end}
80
+ − 813
\end{graybox}
75
+ − 814
\caption{\small The file @{text "Command.thy"} is necessary for generating a log
66
+ − 815
file. This log file enables Isabelle to generate a keyword file containing
68
+ − 816
the command \isacommand{foobar}.\label{fig:commandtheory}}
66
+ − 817
\end{figure}
+ − 818
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+ − 819
75
+ − 820
For our purposes it is sufficient to use the log files of the theories
68
+ − 821
@{text "Pure"}, @{text "HOL"} and @{text "Pure-ProofGeneral"}, as well as
75
+ − 822
the log file for the theory @{text "Command.thy"}, which contains the new
+ − 823
\isacommand{foobar}-command. If you target other logics besides HOL, such
74
+ − 824
as Nominal or ZF, then you need to adapt the log files appropriately.
104
+ − 825
74
+ − 826
@{text Pure} and @{text HOL} are usually compiled during the installation of
+ − 827
Isabelle. So log files for them should be already available. If not, then
75
+ − 828
they can be conveniently compiled with the help of the build-script from the Isabelle
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changeset
+ − 829
distribution.
65
+ − 830
+ − 831
@{text [display]
+ − 832
"$ ./build -m \"Pure\"
+ − 833
$ ./build -m \"HOL\""}
+ − 834
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+ − 835
The @{text "Pure-ProofGeneral"} theory needs to be compiled with:
65
+ − 836
+ − 837
@{text [display] "$ ./build -m \"Pure-ProofGeneral\" \"Pure\""}
+ − 838
101
+ − 839
For the theory @{text "Command.thy"}, you first need to create a ``managed'' subdirectory
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diff
changeset
+ − 840
with:
66
+ − 841
68
+ − 842
@{text [display] "$ isabelle mkdir FoobarCommand"}
66
+ − 843
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changeset
+ − 844
This generates a directory containing the files:
66
+ − 845
+ − 846
@{text [display]
+ − 847
"./IsaMakefile
68
+ − 848
./FoobarCommand/ROOT.ML
+ − 849
./FoobarCommand/document
+ − 850
./FoobarCommand/document/root.tex"}
65
+ − 851
+ − 852
101
+ − 853
You need to copy the file @{text "Command.thy"} into the directory @{text "FoobarCommand"}
66
+ − 854
and add the line
+ − 855
207
+ − 856
@{text [display] "no_document use_thy \"Command\";"}
66
+ − 857
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diff
changeset
+ − 858
to the file @{text "./FoobarCommand/ROOT.ML"}. You can now compile the theory by just typing:
65
+ − 859
+ − 860
@{text [display] "$ isabelle make"}
+ − 861
101
+ − 862
If the compilation succeeds, you have finally created all the necessary log files.
+ − 863
They are stored in the directory
65
+ − 864
66
+ − 865
@{text [display] "~/.isabelle/heaps/Isabelle2008/polyml-5.2.1_x86-linux/log"}
65
+ − 866
74
+ − 867
or something similar depending on your Isabelle distribution and architecture.
+ − 868
One quick way to assign a shell variable to this directory is by typing
66
+ − 869
+ − 870
@{text [display] "$ ISABELLE_LOGS=\"$(isabelle getenv -b ISABELLE_OUTPUT)\"/log"}
+ − 871
156
+ − 872
on the Unix prompt. If you now type @{text "ls $ISABELLE_LOGS"}, then the
128
+ − 873
directory should include the files:
65
+ − 874
+ − 875
@{text [display]
+ − 876
"Pure.gz
+ − 877
HOL.gz
+ − 878
Pure-ProofGeneral.gz
68
+ − 879
HOL-FoobarCommand.gz"}
65
+ − 880
101
+ − 881
From them you can create the keyword files. Assuming the name
75
+ − 882
of the directory is in @{text "$ISABELLE_LOGS"},
74
+ − 883
then the Unix command for creating the keyword file is:
65
+ − 884
+ − 885
@{text [display]
68
+ − 886
"$ isabelle keywords -k foobar
80
+ − 887
$ISABELLE_LOGS/{Pure.gz,HOL.gz,Pure-ProofGeneral.gz,HOL-FoobarCommand.gz}"}
65
+ − 888
80
+ − 889
The result is the file @{text "isar-keywords-foobar.el"}. It should contain
86
+ − 890
the string @{text "foobar"} twice.\footnote{To see whether things are fine, check
80
+ − 891
that @{text "grep foobar"} on this file returns something
86
+ − 892
non-empty.} This keyword file needs to
80
+ − 893
be copied into the directory @{text "~/.isabelle/etc"}. To make Isabelle
101
+ − 894
aware of this keyword file, you have to start Isabelle with the option @{text
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diff
changeset
+ − 895
"-k foobar"}, that is:
65
+ − 896
80
+ − 897
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diff
changeset
+ − 898
@{text [display] "$ isabelle emacs -k foobar a_theory_file"}
65
+ − 899
101
+ − 900
If you now build a theory on top of @{text "Command.thy"},
+ − 901
then the command \isacommand{foobar} can be used.
74
+ − 902
Similarly with any other new command.
65
+ − 903
+ − 904
75
+ − 905
At the moment \isacommand{foobar} is not very useful. Let us refine it a bit
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diff
changeset
+ − 906
next by letting it take a proposition as argument and printing this proposition
5e309df58557
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diff
changeset
+ − 907
inside the tracing buffer.
68
+ − 908
75
+ − 909
The crucial part of a command is the function that determines the behaviour
+ − 910
of the command. In the code above we used a ``do-nothing''-function, which
+ − 911
because of @{ML Scan.succeed} does not parse any argument, but immediately
+ − 912
returns the simple toplevel function @{ML "Toplevel.theory I"}. We can
+ − 913
replace this code by a function that first parses a proposition (using the
+ − 914
parser @{ML OuterParse.prop}), then prints out the tracing
+ − 915
information (using a new top-level function @{text trace_top_lvl}) and
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diff
changeset
+ − 916
finally does nothing. For this you can write:
68
+ − 917
*}
+ − 918
69
+ − 919
ML{*let
75
+ − 920
fun trace_top_lvl str =
+ − 921
Toplevel.theory (fn thy => (tracing str; thy))
+ − 922
+ − 923
val trace_prop = OuterParse.prop >> trace_top_lvl
+ − 924
68
+ − 925
val kind = OuterKeyword.thy_decl
+ − 926
in
+ − 927
OuterSyntax.command "foobar" "traces a proposition" kind trace_prop
69
+ − 928
end *}
68
+ − 929
+ − 930
text {*
102
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diff
changeset
+ − 931
Now you can type
68
+ − 932
74
+ − 933
\begin{isabelle}
+ − 934
\isacommand{foobar}~@{text [quotes] "True \<and> False"}\\
75
+ − 935
@{text "> \"True \<and> False\""}
74
+ − 936
\end{isabelle}
68
+ − 937
+ − 938
and see the proposition in the tracing buffer.
+ − 939
74
+ − 940
Note that so far we used @{ML thy_decl in OuterKeyword} as the kind indicator
68
+ − 941
for the command. This means that the command finishes as soon as the
+ − 942
arguments are processed. Examples of this kind of commands are
75
+ − 943
\isacommand{definition} and \isacommand{declare}. In other cases,
68
+ − 944
commands are expected to parse some arguments, for example a proposition,
75
+ − 945
and then ``open up'' a proof in order to prove the proposition (for example
86
+ − 946
\isacommand{lemma}) or prove some other properties (for example
104
+ − 947
\isacommand{function}). To achieve this kind of behaviour, you have to use the kind
149
+ − 948
indicator @{ML thy_goal in OuterKeyword}. Note, however, once you change the
+ − 949
``kind'' of a command from @{ML thy_decl in OuterKeyword} to @{ML thy_goal in OuterKeyword}
186
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diff
changeset
+ − 950
then the keyword file needs to be re-created!
68
+ − 951
75
+ − 952
Below we change \isacommand{foobar} so that it takes a proposition as
102
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diff
changeset
+ − 953
argument and then starts a proof in order to prove it. Therefore in Line 13,
5e309df58557
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diff
changeset
+ − 954
we set the kind indicator to @{ML thy_goal in OuterKeyword}.
68
+ − 955
*}
+ − 956
114
+ − 957
ML%linenosgray{*let
68
+ − 958
fun set_up_thm str ctxt =
+ − 959
let
+ − 960
val prop = Syntax.read_prop ctxt str
+ − 961
in
75
+ − 962
Proof.theorem_i NONE (K I) [[(prop,[])]] ctxt
68
+ − 963
end;
+ − 964
+ − 965
val prove_prop = OuterParse.prop >>
+ − 966
(fn str => Toplevel.print o
+ − 967
Toplevel.local_theory_to_proof NONE (set_up_thm str))
+ − 968
+ − 969
val kind = OuterKeyword.thy_goal
+ − 970
in
+ − 971
OuterSyntax.command "foobar" "proving a proposition" kind prove_prop
69
+ − 972
end *}
68
+ − 973
+ − 974
text {*
86
+ − 975
The function @{text set_up_thm} in Lines 2 to 7 takes a string (the proposition to be
102
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diff
changeset
+ − 976
proved) and a context as argument. The context is necessary in order to be able to use
74
+ − 977
@{ML Syntax.read_prop}, which converts a string into a proper proposition.
75
+ − 978
In Line 6 the function @{ML Proof.theorem_i} starts the proof for the
+ − 979
proposition. Its argument @{ML NONE} stands for a locale (which we chose to
+ − 980
omit); the argument @{ML "(K I)"} stands for a function that determines what
+ − 981
should be done with the theorem once it is proved (we chose to just forget
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diff
changeset
+ − 982
about it). Lines 9 to 11 contain the parser for the proposition.
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diff
changeset
+ − 983
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diff
changeset
+ − 984
If you now type \isacommand{foobar}~@{text [quotes] "True \<and> True"}, you obtain the following
68
+ − 985
proof state:
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diff
changeset
+ − 986
74
+ − 987
\begin{isabelle}
80
+ − 988
\isacommand{foobar}~@{text [quotes] "True \<and> True"}\\
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diff
changeset
+ − 989
@{text "goal (1 subgoal):"}\\
74
+ − 990
@{text "1. True \<and> True"}
+ − 991
\end{isabelle}
68
+ − 992
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+ − 993
and you can build the proof
68
+ − 994
74
+ − 995
\begin{isabelle}
80
+ − 996
\isacommand{foobar}~@{text [quotes] "True \<and> True"}\\
74
+ − 997
\isacommand{apply}@{text "(rule conjI)"}\\
+ − 998
\isacommand{apply}@{text "(rule TrueI)+"}\\
+ − 999
\isacommand{done}
+ − 1000
\end{isabelle}
+ − 1001
149
+ − 1002
68
+ − 1003
101
+ − 1004
(FIXME What do @{ML "Toplevel.theory"}
+ − 1005
@{ML "Toplevel.print"}
128
+ − 1006
@{ML Toplevel.local_theory} do?)
101
+ − 1007
75
+ − 1008
(FIXME read a name and show how to store theorems)
65
+ − 1009
*}
+ − 1010
211
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+ − 1011
section {* Methods (TBD) *}
178
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+ − 1012
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+ − 1013
text {*
207
+ − 1014
(FIXME: maybe move to after the tactic section)
+ − 1015
+ − 1016
Methods are a central to Isabelle. They are the ones you use for example
186
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+ − 1017
in \isacommand{apply}. To print out all currently known methods you can use the
192
+ − 1018
Isabelle command:
178
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+ − 1019
207
+ − 1020
\begin{isabelle}
+ − 1021
\isacommand{print\_methods}\\
+ − 1022
@{text "> methods:"}\\
+ − 1023
@{text "> -: do nothing (insert current facts only)"}\\
+ − 1024
@{text "> HOL.default: apply some intro/elim rule (potentially classical)"}\\
+ − 1025
@{text "> ..."}
+ − 1026
\end{isabelle}
178
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+ − 1027
193
+ − 1028
An example of a very simple method is:
178
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+ − 1029
*}
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+ − 1030
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+ − 1031
method_setup %gray foobar_meth =
181
+ − 1032
{* Scan.succeed
+ − 1033
(K (SIMPLE_METHOD ((etac @{thm conjE} THEN' rtac @{thm conjI}) 1))) *}
207
+ − 1034
"foobar method for conjE and conjI"
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+ − 1035
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+ − 1036
text {*
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+ − 1037
It defines the method @{text foobar_meth}, which takes no arguments (therefore the
207
+ − 1038
parser @{ML Scan.succeed}) and only applies a single tactic, namely the tactic which
+ − 1039
applies @{thm [source] conjE} and then @{thm [source] conjI}. The function @{ML SIMPLE_METHOD}
+ − 1040
turns such a tactic into a method. @{text "Foobar_meth"} can be used as follows
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+ − 1041
*}
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+ − 1042
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+ − 1043
lemma shows "A \<and> B \<Longrightarrow> C \<and> D"
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+ − 1044
apply(foobar_meth)
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+ − 1045
txt {*
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+ − 1046
where it results in the goal state
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+ − 1047
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+ − 1048
\begin{minipage}{\textwidth}
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+ − 1049
@{subgoals}
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+ − 1050
\end{minipage} *}
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+ − 1051
(*<*)oops(*>*)
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+ − 1052
193
+ − 1053
+ − 1054
(*
+ − 1055
ML {* SIMPLE_METHOD *}
+ − 1056
ML {* METHOD *}
+ − 1057
ML {* K (SIMPLE_METHOD ((etac @{thm conjE} THEN' rtac @{thm conjI}) 1)) *}
+ − 1058
ML {* Scan.succeed *}
+ − 1059
*)
+ − 1060
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+ − 1061
text {*
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+ − 1062
(FIXME: explain a version of rule-tac)
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+ − 1063
*}
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+ − 1064
75
+ − 1065
(*<*)
194
+ − 1066
(* THIS IS AN OLD VERSION OF THE PARSING CHAPTER BY JEREMY DAWSON *)
38
+ − 1067
chapter {* Parsing *}
+ − 1068
+ − 1069
text {*
+ − 1070
4
+ − 1071
Lots of Standard ML code is given in this document, for various reasons,
+ − 1072
including:
+ − 1073
\begin{itemize}
+ − 1074
\item direct quotation of code found in the Isabelle source files,
+ − 1075
or simplified versions of such code
+ − 1076
\item identifiers found in the Isabelle source code, with their types
+ − 1077
(or specialisations of their types)
+ − 1078
\item code examples, which can be run by the reader, to help illustrate the
+ − 1079
behaviour of functions found in the Isabelle source code
+ − 1080
\item ancillary functions, not from the Isabelle source code,
+ − 1081
which enable the reader to run relevant code examples
+ − 1082
\item type abbreviations, which help explain the uses of certain functions
+ − 1083
\end{itemize}
+ − 1084
+ − 1085
*}
+ − 1086
+ − 1087
section {* Parsing Isar input *}
+ − 1088
+ − 1089
text {*
+ − 1090
+ − 1091
The typical parsing function has the type
+ − 1092
\texttt{'src -> 'res * 'src}, with input
+ − 1093
of type \texttt{'src}, returning a result
+ − 1094
of type \texttt{'res}, which is (or is derived from) the first part of the
+ − 1095
input, and also returning the remainder of the input.
+ − 1096
(In the common case, when it is clear what the ``remainder of the input''
+ − 1097
means, we will just say that the functions ``returns'' the
+ − 1098
value of type \texttt{'res}).
+ − 1099
An exception is raised if an appropriate value
+ − 1100
cannot be produced from the input.
+ − 1101
A range of exceptions can be used to identify different reasons
+ − 1102
for the failure of a parse.
+ − 1103
+ − 1104
This contrasts the standard parsing function in Standard ML,
+ − 1105
which is of type
+ − 1106
\texttt{type ('res, 'src) reader = 'src -> ('res * 'src) option};
+ − 1107
(for example, \texttt{List.getItem} and \texttt{Substring.getc}).
+ − 1108
However, much of the discussion at
+ − 1109
FIX file:/home/jeremy/html/ml/SMLBasis/string-cvt.html
+ − 1110
is relevant.
+ − 1111
+ − 1112
Naturally one may convert between the two different sorts of parsing functions
+ − 1113
as follows:
+ − 1114
\begin{verbatim}
+ − 1115
open StringCvt ;
+ − 1116
type ('res, 'src) ex_reader = 'src -> 'res * 'src
75
+ − 1117
ex_reader : ('res, 'src) reader -> ('res, 'src) ex_reader
4
+ − 1118
fun ex_reader rdr src = Option.valOf (rdr src) ;
75
+ − 1119
reader : ('res, 'src) ex_reader -> ('res, 'src) reader
4
+ − 1120
fun reader exrdr src = SOME (exrdr src) handle _ => NONE ;
+ − 1121
\end{verbatim}
+ − 1122
+ − 1123
*}
+ − 1124
+ − 1125
section{* The \texttt{Scan} structure *}
+ − 1126
+ − 1127
text {*
+ − 1128
The source file is \texttt{src/General/scan.ML}.
+ − 1129
This structure provides functions for using and combining parsing functions
+ − 1130
of the type \texttt{'src -> 'res * 'src}.
+ − 1131
Three exceptions are used:
+ − 1132
\begin{verbatim}
+ − 1133
exception MORE of string option; (*need more input (prompt)*)
+ − 1134
exception FAIL of string option; (*try alternatives (reason of failure)*)
+ − 1135
exception ABORT of string; (*dead end*)
+ − 1136
\end{verbatim}
+ − 1137
Many functions in this structure (generally those with names composed of
+ − 1138
symbols) are declared as infix.
+ − 1139
+ − 1140
Some functions from that structure are
+ − 1141
\begin{verbatim}
+ − 1142
|-- : ('src -> 'res1 * 'src') * ('src' -> 'res2 * 'src'') ->
+ − 1143
'src -> 'res2 * 'src''
+ − 1144
--| : ('src -> 'res1 * 'src') * ('src' -> 'res2 * 'src'') ->
+ − 1145
'src -> 'res1 * 'src''
+ − 1146
-- : ('src -> 'res1 * 'src') * ('src' -> 'res2 * 'src'') ->
+ − 1147
'src -> ('res1 * 'res2) * 'src''
+ − 1148
^^ : ('src -> string * 'src') * ('src' -> string * 'src'') ->
+ − 1149
'src -> string * 'src''
+ − 1150
\end{verbatim}
+ − 1151
These functions parse a result off the input source twice.
+ − 1152
+ − 1153
\texttt{|--} and \texttt{--|}
+ − 1154
return the first result and the second result, respectively.
+ − 1155
+ − 1156
\texttt{--} returns both.
+ − 1157
+ − 1158
\verb|^^| returns the result of concatenating the two results
+ − 1159
(which must be strings).
+ − 1160
+ − 1161
Note how, although the types
+ − 1162
\texttt{'src}, \texttt{'src'} and \texttt{'src''} will normally be the same,
+ − 1163
the types as shown help suggest the behaviour of the functions.
+ − 1164
\begin{verbatim}
+ − 1165
:-- : ('src -> 'res1 * 'src') * ('res1 -> 'src' -> 'res2 * 'src'') ->
+ − 1166
'src -> ('res1 * 'res2) * 'src''
+ − 1167
:|-- : ('src -> 'res1 * 'src') * ('res1 -> 'src' -> 'res2 * 'src'') ->
+ − 1168
'src -> 'res2 * 'src''
+ − 1169
\end{verbatim}
+ − 1170
These are similar to \texttt{|--} and \texttt{--|},
+ − 1171
except that the second parsing function can depend on the result of the first.
+ − 1172
\begin{verbatim}
+ − 1173
>> : ('src -> 'res1 * 'src') * ('res1 -> 'res2) -> 'src -> 'res2 * 'src'
+ − 1174
|| : ('src -> 'res_src) * ('src -> 'res_src) -> 'src -> 'res_src
+ − 1175
\end{verbatim}
+ − 1176
\texttt{p >> f} applies a function \texttt{f} to the result of a parse.
+ − 1177
+ − 1178
\texttt{||} tries a second parsing function if the first one
+ − 1179
fails by raising an exception of the form \texttt{FAIL \_}.
+ − 1180
+ − 1181
\begin{verbatim}
+ − 1182
succeed : 'res -> ('src -> 'res * 'src) ;
+ − 1183
fail : ('src -> 'res_src) ;
+ − 1184
!! : ('src * string option -> string) ->
+ − 1185
('src -> 'res_src) -> ('src -> 'res_src) ;
+ − 1186
\end{verbatim}
+ − 1187
\texttt{succeed r} returns \texttt{r}, with the input unchanged.
+ − 1188
\texttt{fail} always fails, raising exception \texttt{FAIL NONE}.
+ − 1189
\texttt{!! f} only affects the failure mode, turning a failure that
+ − 1190
raises \texttt{FAIL \_} into a failure that raises \texttt{ABORT ...}.
+ − 1191
This is used to prevent recovery from the failure ---
+ − 1192
thus, in \texttt{!! parse1 || parse2}, if \texttt{parse1} fails,
+ − 1193
it won't recover by trying \texttt{parse2}.
+ − 1194
+ − 1195
\begin{verbatim}
+ − 1196
one : ('si -> bool) -> ('si list -> 'si * 'si list) ;
+ − 1197
some : ('si -> 'res option) -> ('si list -> 'res * 'si list) ;
+ − 1198
\end{verbatim}
+ − 1199
These require the input to be a list of items:
+ − 1200
they fail, raising \texttt{MORE NONE} if the list is empty.
+ − 1201
On other failures they raise \texttt{FAIL NONE}
+ − 1202
+ − 1203
\texttt{one p} takes the first
+ − 1204
item from the list if it satisfies \texttt{p}, otherwise fails.
+ − 1205
+ − 1206
\texttt{some f} takes the first
+ − 1207
item from the list and applies \texttt{f} to it, failing if this returns
+ − 1208
\texttt{NONE}.
+ − 1209
+ − 1210
\begin{verbatim}
+ − 1211
many : ('si -> bool) -> 'si list -> 'si list * 'si list ;
+ − 1212
\end{verbatim}
+ − 1213
\texttt{many p} takes items from the input until it encounters one
+ − 1214
which does not satisfy \texttt{p}. If it reaches the end of the input
+ − 1215
it fails, raising \texttt{MORE NONE}.
+ − 1216
+ − 1217
\texttt{many1} (with the same type) fails if the first item
+ − 1218
does not satisfy \texttt{p}.
+ − 1219
+ − 1220
\begin{verbatim}
+ − 1221
option : ('src -> 'res * 'src) -> ('src -> 'res option * 'src)
+ − 1222
optional : ('src -> 'res * 'src) -> 'res -> ('src -> 'res * 'src)
+ − 1223
\end{verbatim}
+ − 1224
\texttt{option}:
+ − 1225
where the parser \texttt{f} succeeds with result \texttt{r}
+ − 1226
or raises \texttt{FAIL \_},
+ − 1227
\texttt{option f} gives the result \texttt{SOME r} or \texttt{NONE}.
+ − 1228
+ − 1229
\texttt{optional}: if parser \texttt{f} fails by raising \texttt{FAIL \_},
+ − 1230
\texttt{optional f default} provides the result \texttt{default}.
+ − 1231
+ − 1232
\begin{verbatim}
+ − 1233
repeat : ('src -> 'res * 'src) -> 'src -> 'res list * 'src
+ − 1234
repeat1 : ('src -> 'res * 'src) -> 'src -> 'res list * 'src
+ − 1235
bulk : ('src -> 'res * 'src) -> 'src -> 'res list * 'src
+ − 1236
\end{verbatim}
+ − 1237
\texttt{repeat f} repeatedly parses an item off the remaining input until
+ − 1238
\texttt{f} fails with \texttt{FAIL \_}
+ − 1239
+ − 1240
\texttt{repeat1} is as for \texttt{repeat}, but requires at least one
+ − 1241
successful parse.
+ − 1242
+ − 1243
\begin{verbatim}
+ − 1244
lift : ('src -> 'res * 'src) -> ('ex * 'src -> 'res * ('ex * 'src))
+ − 1245
\end{verbatim}
+ − 1246
\texttt{lift} changes the source type of a parser by putting in an extra
+ − 1247
component \texttt{'ex}, which is ignored in the parsing.
+ − 1248
+ − 1249
The \texttt{Scan} structure also provides the type \texttt{lexicon},
+ − 1250
HOW DO THEY WORK ?? TO BE COMPLETED
+ − 1251
\begin{verbatim}
+ − 1252
dest_lexicon: lexicon -> string list ;
+ − 1253
make_lexicon: string list list -> lexicon ;
+ − 1254
empty_lexicon: lexicon ;
+ − 1255
extend_lexicon: string list list -> lexicon -> lexicon ;
+ − 1256
merge_lexicons: lexicon -> lexicon -> lexicon ;
+ − 1257
is_literal: lexicon -> string list -> bool ;
+ − 1258
literal: lexicon -> string list -> string list * string list ;
+ − 1259
\end{verbatim}
+ − 1260
Two lexicons, for the commands and keywords, are stored and can be retrieved
+ − 1261
by:
+ − 1262
\begin{verbatim}
+ − 1263
val (command_lexicon, keyword_lexicon) = OuterSyntax.get_lexicons () ;
+ − 1264
val commands = Scan.dest_lexicon command_lexicon ;
+ − 1265
val keywords = Scan.dest_lexicon keyword_lexicon ;
+ − 1266
\end{verbatim}
+ − 1267
*}
+ − 1268
+ − 1269
section{* The \texttt{OuterLex} structure *}
+ − 1270
+ − 1271
text {*
+ − 1272
The source file is @{text "src/Pure/Isar/outer_lex.ML"}.
+ − 1273
In some other source files its name is abbreviated:
+ − 1274
\begin{verbatim}
+ − 1275
structure T = OuterLex;
+ − 1276
\end{verbatim}
+ − 1277
This structure defines the type \texttt{token}.
+ − 1278
(The types
+ − 1279
\texttt{OuterLex.token},
+ − 1280
\texttt{OuterParse.token} and
+ − 1281
\texttt{SpecParse.token} are all the same).
+ − 1282
+ − 1283
Input text is split up into tokens, and the input source type for many parsing
+ − 1284
functions is \texttt{token list}.
+ − 1285
+ − 1286
The datatype definition (which is not published in the signature) is
+ − 1287
\begin{verbatim}
+ − 1288
datatype token = Token of Position.T * (token_kind * string);
+ − 1289
\end{verbatim}
+ − 1290
but here are some runnable examples for viewing tokens:
+ − 1291
+ − 1292
*}
+ − 1293
47
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+ − 1294
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+ − 1295
4
+ − 1296
69
+ − 1297
ML{*
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+ − 1298
val toks = OuterSyntax.scan Position.none
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+ − 1299
"theory,imports;begin x.y.z apply ?v1 ?'a 'a -- || 44 simp (* xx *) { * fff * }" ;
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+ − 1300
*}
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+ − 1301
69
+ − 1302
ML{*
4
+ − 1303
print_depth 20 ;
47
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+ − 1304
*}
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+ − 1305
69
+ − 1306
ML{*
47
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+ − 1307
map OuterLex.text_of toks ;
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diff
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+ − 1308
*}
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+ − 1309
69
+ − 1310
ML{*
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+ − 1311
val proper_toks = filter OuterLex.is_proper toks ;
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+ − 1312
*}
4
+ − 1313
69
+ − 1314
ML{*
47
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+ − 1315
map OuterLex.kind_of proper_toks
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+ − 1316
*}
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+ − 1317
69
+ − 1318
ML{*
47
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+ − 1319
map OuterLex.unparse proper_toks ;
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+ − 1320
*}
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+ − 1321
69
+ − 1322
ML{*
47
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changeset
+ − 1323
OuterLex.stopper
4
+ − 1324
*}
+ − 1325
+ − 1326
text {*
+ − 1327
+ − 1328
The function \texttt{is\_proper : token -> bool} identifies tokens which are
+ − 1329
not white space or comments: many parsing functions assume require spaces or
+ − 1330
comments to have been filtered out.
+ − 1331
+ − 1332
There is a special end-of-file token:
+ − 1333
\begin{verbatim}
+ − 1334
val (tok_eof : token, is_eof : token -> bool) = T.stopper ;
+ − 1335
(* end of file token *)
+ − 1336
\end{verbatim}
+ − 1337
+ − 1338
*}
+ − 1339
+ − 1340
section {* The \texttt{OuterParse} structure *}
+ − 1341
+ − 1342
text {*
+ − 1343
The source file is \texttt{src/Pure/Isar/outer\_parse.ML}.
+ − 1344
In some other source files its name is abbreviated:
+ − 1345
\begin{verbatim}
+ − 1346
structure P = OuterParse;
+ − 1347
\end{verbatim}
+ − 1348
Here the parsers use \texttt{token list} as the input source type.
+ − 1349
+ − 1350
Some of the parsers simply select the first token, provided that it is of the
+ − 1351
right kind (as returned by \texttt{T.kind\_of}): these are
+ − 1352
\texttt{ command, keyword, short\_ident, long\_ident, sym\_ident, term\_var,
+ − 1353
type\_ident, type\_var, number, string, alt\_string, verbatim, sync, eof}
+ − 1354
Others select the first token, provided that it is one of several kinds,
+ − 1355
(eg, \texttt{name, xname, text, typ}).
+ − 1356
+ − 1357
\begin{verbatim}
+ − 1358
type 'a tlp = token list -> 'a * token list ; (* token list parser *)
+ − 1359
$$$ : string -> string tlp
+ − 1360
nat : int tlp ;
+ − 1361
maybe : 'a tlp -> 'a option tlp ;
+ − 1362
\end{verbatim}
+ − 1363
+ − 1364
\texttt{\$\$\$ s} returns the first token,
+ − 1365
if it equals \texttt{s} \emph{and} \texttt{s} is a keyword.
+ − 1366
+ − 1367
\texttt{nat} returns the first token, if it is a number, and evaluates it.
+ − 1368
+ − 1369
\texttt{maybe}: if \texttt{p} returns \texttt{r},
+ − 1370
then \texttt{maybe p} returns \texttt{SOME r} ;
+ − 1371
if the first token is an underscore, it returns \texttt{NONE}.
+ − 1372
+ − 1373
A few examples:
+ − 1374
\begin{verbatim}
+ − 1375
P.list : 'a tlp -> 'a list tlp ; (* likewise P.list1 *)
+ − 1376
P.and_list : 'a tlp -> 'a list tlp ; (* likewise P.and_list1 *)
+ − 1377
val toks : token list = OuterSyntax.scan "44 ,_, 66,77" ;
+ − 1378
val proper_toks = List.filter T.is_proper toks ;
+ − 1379
P.list P.nat toks ; (* OK, doesn't recognize white space *)
+ − 1380
P.list P.nat proper_toks ; (* fails, doesn't recognize what follows ',' *)
+ − 1381
P.list (P.maybe P.nat) proper_toks ; (* fails, end of input *)
+ − 1382
P.list (P.maybe P.nat) (proper_toks @ [tok_eof]) ; (* OK *)
+ − 1383
val toks : token list = OuterSyntax.scan "44 and 55 and 66 and 77" ;
+ − 1384
P.and_list P.nat (List.filter T.is_proper toks @ [tok_eof]) ; (* ??? *)
+ − 1385
\end{verbatim}
+ − 1386
+ − 1387
The following code helps run examples:
+ − 1388
\begin{verbatim}
+ − 1389
fun parse_str tlp str =
+ − 1390
let val toks : token list = OuterSyntax.scan str ;
+ − 1391
val proper_toks = List.filter T.is_proper toks @ [tok_eof] ;
+ − 1392
val (res, rem_toks) = tlp proper_toks ;
+ − 1393
val rem_str = String.concat
+ − 1394
(Library.separate " " (List.map T.unparse rem_toks)) ;
+ − 1395
in (res, rem_str) end ;
+ − 1396
\end{verbatim}
+ − 1397
+ − 1398
Some examples from \texttt{src/Pure/Isar/outer\_parse.ML}
+ − 1399
\begin{verbatim}
+ − 1400
val type_args =
+ − 1401
type_ident >> Library.single ||
+ − 1402
$$$ "(" |-- !!! (list1 type_ident --| $$$ ")") ||
+ − 1403
Scan.succeed [];
+ − 1404
\end{verbatim}
+ − 1405
There are three ways parsing a list of type arguments can succeed.
+ − 1406
The first line reads a single type argument, and turns it into a singleton
+ − 1407
list.
+ − 1408
The second line reads "(", and then the remainder, ignoring the "(" ;
+ − 1409
the remainder consists of a list of type identifiers (at least one),
+ − 1410
and then a ")" which is also ignored.
+ − 1411
The \texttt{!!!} ensures that if the parsing proceeds this far and then fails,
+ − 1412
it won't try the third line (see the description of \texttt{Scan.!!}).
+ − 1413
The third line consumes no input and returns the empty list.
+ − 1414
+ − 1415
\begin{verbatim}
+ − 1416
fun triple2 (x, (y, z)) = (x, y, z);
+ − 1417
val arity = xname -- ($$$ "::" |-- !!! (
+ − 1418
Scan.optional ($$$ "(" |-- !!! (list1 sort --| $$$ ")")) []
+ − 1419
-- sort)) >> triple2;
+ − 1420
\end{verbatim}
+ − 1421
The parser \texttt{arity} reads a typename $t$, then ``\texttt{::}'' (which is
+ − 1422
ignored), then optionally a list $ss$ of sorts and then another sort $s$.
+ − 1423
The result $(t, (ss, s))$ is transformed by \texttt{triple2} to $(t, ss, s)$.
+ − 1424
The second line reads the optional list of sorts:
+ − 1425
it reads first ``\texttt{(}'' and last ``\texttt{)}'', which are both ignored,
+ − 1426
and between them a comma-separated list of sorts.
+ − 1427
If this list is absent, the default \texttt{[]} provides the list of sorts.
+ − 1428
+ − 1429
\begin{verbatim}
+ − 1430
parse_str P.type_args "('a, 'b) ntyp" ;
+ − 1431
parse_str P.type_args "'a ntyp" ;
+ − 1432
parse_str P.type_args "ntyp" ;
+ − 1433
parse_str P.arity "ty :: tycl" ;
+ − 1434
parse_str P.arity "ty :: (tycl1, tycl2) tycl" ;
+ − 1435
\end{verbatim}
+ − 1436
+ − 1437
*}
+ − 1438
+ − 1439
section {* The \texttt{SpecParse} structure *}
+ − 1440
+ − 1441
text {*
+ − 1442
The source file is \texttt{src/Pure/Isar/spec\_parse.ML}.
+ − 1443
This structure contains token list parsers for more complicated values.
+ − 1444
For example,
+ − 1445
\begin{verbatim}
+ − 1446
open SpecParse ;
+ − 1447
attrib : Attrib.src tok_rdr ;
+ − 1448
attribs : Attrib.src list tok_rdr ;
+ − 1449
opt_attribs : Attrib.src list tok_rdr ;
+ − 1450
xthm : (thmref * Attrib.src list) tok_rdr ;
+ − 1451
xthms1 : (thmref * Attrib.src list) list tok_rdr ;
+ − 1452
+ − 1453
parse_str attrib "simp" ;
+ − 1454
parse_str opt_attribs "hello" ;
+ − 1455
val (ass, "") = parse_str attribs "[standard, xxxx, simp, intro, OF sym]" ;
+ − 1456
map Args.dest_src ass ;
+ − 1457
val (asrc, "") = parse_str attrib "THEN trans [THEN sym]" ;
+ − 1458
+ − 1459
parse_str xthm "mythm [attr]" ;
+ − 1460
parse_str xthms1 "thm1 [attr] thms2" ;
+ − 1461
\end{verbatim}
+ − 1462
+ − 1463
As you can see, attributes are described using types of the \texttt{Args}
+ − 1464
structure, described below.
+ − 1465
*}
+ − 1466
+ − 1467
section{* The \texttt{Args} structure *}
+ − 1468
+ − 1469
text {*
+ − 1470
The source file is \texttt{src/Pure/Isar/args.ML}.
+ − 1471
The primary type of this structure is the \texttt{src} datatype;
+ − 1472
the single constructors not published in the signature, but
+ − 1473
\texttt{Args.src} and \texttt{Args.dest\_src}
+ − 1474
are in fact the constructor and destructor functions.
+ − 1475
Note that the types \texttt{Attrib.src} and \texttt{Method.src}
+ − 1476
are in fact \texttt{Args.src}.
+ − 1477
+ − 1478
\begin{verbatim}
+ − 1479
src : (string * Args.T list) * Position.T -> Args.src ;
+ − 1480
dest_src : Args.src -> (string * Args.T list) * Position.T ;
+ − 1481
Args.pretty_src : Proof.context -> Args.src -> Pretty.T ;
+ − 1482
fun pr_src ctxt src = Pretty.string_of (Args.pretty_src ctxt src) ;
+ − 1483
+ − 1484
val thy = ML_Context.the_context () ;
+ − 1485
val ctxt = ProofContext.init thy ;
+ − 1486
map (pr_src ctxt) ass ;
+ − 1487
\end{verbatim}
+ − 1488
+ − 1489
So an \texttt{Args.src} consists of the first word, then a list of further
+ − 1490
``arguments'', of type \texttt{Args.T}, with information about position in the
+ − 1491
input.
+ − 1492
\begin{verbatim}
+ − 1493
(* how an Args.src is parsed *)
+ − 1494
P.position : 'a tlp -> ('a * Position.T) tlp ;
+ − 1495
P.arguments : Args.T list tlp ;
+ − 1496
+ − 1497
val parse_src : Args.src tlp =
+ − 1498
P.position (P.xname -- P.arguments) >> Args.src ;
+ − 1499
\end{verbatim}
+ − 1500
+ − 1501
\begin{verbatim}
+ − 1502
val ((first_word, args), pos) = Args.dest_src asrc ;
+ − 1503
map Args.string_of args ;
+ − 1504
\end{verbatim}
+ − 1505
+ − 1506
The \texttt{Args} structure contains more parsers and parser transformers
+ − 1507
for which the input source type is \texttt{Args.T list}. For example,
+ − 1508
\begin{verbatim}
+ − 1509
type 'a atlp = Args.T list -> 'a * Args.T list ;
+ − 1510
open Args ;
+ − 1511
nat : int atlp ; (* also Args.int *)
+ − 1512
thm_sel : PureThy.interval list atlp ;
+ − 1513
list : 'a atlp -> 'a list atlp ;
+ − 1514
attribs : (string -> string) -> Args.src list atlp ;
+ − 1515
opt_attribs : (string -> string) -> Args.src list atlp ;
+ − 1516
+ − 1517
(* parse_atl_str : 'a atlp -> (string -> 'a * string) ;
+ − 1518
given an Args.T list parser, to get a string parser *)
+ − 1519
fun parse_atl_str atlp str =
+ − 1520
let val (ats, rem_str) = parse_str P.arguments str ;
+ − 1521
val (res, rem_ats) = atlp ats ;
+ − 1522
in (res, String.concat (Library.separate " "
+ − 1523
(List.map Args.string_of rem_ats @ [rem_str]))) end ;
+ − 1524
+ − 1525
parse_atl_str Args.int "-1-," ;
+ − 1526
parse_atl_str (Scan.option Args.int) "x1-," ;
+ − 1527
parse_atl_str Args.thm_sel "(1-,4,13-22)" ;
+ − 1528
+ − 1529
val (ats as atsrc :: _, "") = parse_atl_str (Args.attribs I)
+ − 1530
"[THEN trans [THEN sym], simp, OF sym]" ;
+ − 1531
\end{verbatim}
+ − 1532
+ − 1533
From here, an attribute is interpreted using \texttt{Attrib.attribute}.
+ − 1534
+ − 1535
\texttt{Args} has a large number of functions which parse an \texttt{Args.src}
+ − 1536
and also refer to a generic context.
+ − 1537
Note the use of \texttt{Scan.lift} for this.
+ − 1538
(as does \texttt{Attrib} - RETHINK THIS)
+ − 1539
+ − 1540
(\texttt{Args.syntax} shown below has type specialised)
+ − 1541
+ − 1542
\begin{verbatim}
+ − 1543
type ('res, 'src) parse_fn = 'src -> 'res * 'src ;
+ − 1544
type 'a cgatlp = ('a, Context.generic * Args.T list) parse_fn ;
+ − 1545
Scan.lift : 'a atlp -> 'a cgatlp ;
+ − 1546
term : term cgatlp ;
+ − 1547
typ : typ cgatlp ;
+ − 1548
+ − 1549
Args.syntax : string -> 'res cgatlp -> src -> ('res, Context.generic) parse_fn ;
+ − 1550
Attrib.thm : thm cgatlp ;
+ − 1551
Attrib.thms : thm list cgatlp ;
+ − 1552
Attrib.multi_thm : thm list cgatlp ;
+ − 1553
+ − 1554
(* parse_cgatl_str : 'a cgatlp -> (string -> 'a * string) ;
+ − 1555
given a (Context.generic * Args.T list) parser, to get a string parser *)
+ − 1556
fun parse_cgatl_str cgatlp str =
+ − 1557
let
+ − 1558
(* use the current generic context *)
+ − 1559
val generic = Context.Theory thy ;
+ − 1560
val (ats, rem_str) = parse_str P.arguments str ;
+ − 1561
(* ignore any change to the generic context *)
+ − 1562
val (res, (_, rem_ats)) = cgatlp (generic, ats) ;
+ − 1563
in (res, String.concat (Library.separate " "
+ − 1564
(List.map Args.string_of rem_ats @ [rem_str]))) end ;
+ − 1565
\end{verbatim}
+ − 1566
*}
+ − 1567
+ − 1568
section{* Attributes, and the \texttt{Attrib} structure *}
+ − 1569
+ − 1570
text {*
+ − 1571
The type \texttt{attribute} is declared in \texttt{src/Pure/thm.ML}.
+ − 1572
The source file for the \texttt{Attrib} structure is
+ − 1573
\texttt{src/Pure/Isar/attrib.ML}.
+ − 1574
Most attributes use a theorem to change a generic context (for example,
+ − 1575
by declaring that the theorem should be used, by default, in simplification),
+ − 1576
or change a theorem (which most often involves referring to the current
+ − 1577
theory).
+ − 1578
The functions \texttt{Thm.rule\_attribute} and
+ − 1579
\texttt{Thm.declaration\_attribute} create attributes of these kinds.
+ − 1580
+ − 1581
\begin{verbatim}
+ − 1582
type attribute = Context.generic * thm -> Context.generic * thm;
+ − 1583
type 'a trf = 'a -> 'a ; (* transformer of a given type *)
+ − 1584
Thm.rule_attribute : (Context.generic -> thm -> thm) -> attribute ;
+ − 1585
Thm.declaration_attribute : (thm -> Context.generic trf) -> attribute ;
+ − 1586
+ − 1587
Attrib.print_attributes : theory -> unit ;
+ − 1588
Attrib.pretty_attribs : Proof.context -> src list -> Pretty.T list ;
+ − 1589
+ − 1590
List.app Pretty.writeln (Attrib.pretty_attribs ctxt ass) ;
+ − 1591
\end{verbatim}
+ − 1592
+ − 1593
An attribute is stored in a theory as indicated by:
+ − 1594
\begin{verbatim}
+ − 1595
Attrib.add_attributes :
+ − 1596
(bstring * (src -> attribute) * string) list -> theory trf ;
+ − 1597
(*
+ − 1598
Attrib.add_attributes [("THEN", THEN_att, "resolution with rule")] ;
+ − 1599
*)
+ − 1600
\end{verbatim}
+ − 1601
where the first and third arguments are name and description of the attribute,
+ − 1602
and the second is a function which parses the attribute input text
+ − 1603
(including the attribute name, which has necessarily already been parsed).
+ − 1604
Here, \texttt{THEN\_att} is a function declared in the code for the
+ − 1605
structure \texttt{Attrib}, but not published in its signature.
+ − 1606
The source file \texttt{src/Pure/Isar/attrib.ML} shows the use of
+ − 1607
\texttt{Attrib.add\_attributes} to add a number of attributes.
+ − 1608
+ − 1609
\begin{verbatim}
+ − 1610
FullAttrib.THEN_att : src -> attribute ;
+ − 1611
FullAttrib.THEN_att atsrc (generic, ML_Context.thm "sym") ;
+ − 1612
FullAttrib.THEN_att atsrc (generic, ML_Context.thm "all_comm") ;
+ − 1613
\end{verbatim}
+ − 1614
+ − 1615
\begin{verbatim}
+ − 1616
Attrib.syntax : attribute cgatlp -> src -> attribute ;
+ − 1617
Attrib.no_args : attribute -> src -> attribute ;
+ − 1618
\end{verbatim}
+ − 1619
When this is called as \texttt{syntax scan src (gc, th)}
+ − 1620
the generic context \texttt{gc} is used
+ − 1621
(and potentially changed to \texttt{gc'})
+ − 1622
by \texttt{scan} in parsing to obtain an attribute \texttt{attr} which would
+ − 1623
then be applied to \texttt{(gc', th)}.
+ − 1624
The source for parsing the attribute is the arguments part of \texttt{src},
+ − 1625
which must all be consumed by the parse.
+ − 1626
+ − 1627
For example, for \texttt{Attrib.no\_args attr src}, the attribute parser
+ − 1628
simply returns \texttt{attr}, requiring that the arguments part of
+ − 1629
\texttt{src} must be empty.
+ − 1630
+ − 1631
Some examples from \texttt{src/Pure/Isar/attrib.ML}, modified:
+ − 1632
\begin{verbatim}
+ − 1633
fun rot_att_n n (gc, th) = (gc, rotate_prems n th) ;
+ − 1634
rot_att_n : int -> attribute ;
+ − 1635
val rot_arg = Scan.lift (Scan.optional Args.int 1 : int atlp) : int cgatlp ;
+ − 1636
val rotated_att : src -> attribute =
+ − 1637
Attrib.syntax (rot_arg >> rot_att_n : attribute cgatlp) ;
+ − 1638
+ − 1639
val THEN_arg : int cgatlp = Scan.lift
+ − 1640
(Scan.optional (Args.bracks Args.nat : int atlp) 1 : int atlp) ;
+ − 1641
+ − 1642
Attrib.thm : thm cgatlp ;
+ − 1643
+ − 1644
THEN_arg -- Attrib.thm : (int * thm) cgatlp ;
+ − 1645
+ − 1646
fun THEN_att_n (n, tht) (gc, th) = (gc, th RSN (n, tht)) ;
+ − 1647
THEN_att_n : int * thm -> attribute ;
+ − 1648
+ − 1649
val THEN_att : src -> attribute = Attrib.syntax
+ − 1650
(THEN_arg -- Attrib.thm >> THEN_att_n : attribute cgatlp);
+ − 1651
\end{verbatim}
+ − 1652
The functions I've called \texttt{rot\_arg} and \texttt{THEN\_arg}
+ − 1653
read an optional argument, which for \texttt{rotated} is an integer,
+ − 1654
and for \texttt{THEN} is a natural enclosed in square brackets;
+ − 1655
the default, if the argument is absent, is 1 in each case.
+ − 1656
Functions \texttt{rot\_att\_n} and \texttt{THEN\_att\_n} turn these into
+ − 1657
attributes, where \texttt{THEN\_att\_n} also requires a theorem, which is
+ − 1658
parsed by \texttt{Attrib.thm}.
+ − 1659
Infix operators \texttt{--} and \texttt{>>} are in the structure \texttt{Scan}.
+ − 1660
+ − 1661
*}
+ − 1662
+ − 1663
section{* Methods, and the \texttt{Method} structure *}
+ − 1664
+ − 1665
text {*
+ − 1666
The source file is \texttt{src/Pure/Isar/method.ML}.
+ − 1667
The type \texttt{method} is defined by the datatype declaration
+ − 1668
\begin{verbatim}
+ − 1669
(* datatype method = Meth of thm list -> cases_tactic; *)
+ − 1670
RuleCases.NO_CASES : tactic -> cases_tactic ;
+ − 1671
\end{verbatim}
+ − 1672
In fact \texttt{RAW\_METHOD\_CASES} (below) is exactly the constructor
+ − 1673
\texttt{Meth}.
+ − 1674
A \texttt{cases\_tactic} is an elaborated version of a tactic.
+ − 1675
\texttt{NO\_CASES tac} is a \texttt{cases\_tactic} which consists of a
+ − 1676
\texttt{cases\_tactic} without any further case information.
+ − 1677
For further details see the description of structure \texttt{RuleCases} below.
+ − 1678
The list of theorems to be passed to a method consists of the current
+ − 1679
\emph{facts} in the proof.
+ − 1680
+ − 1681
\begin{verbatim}
+ − 1682
RAW_METHOD : (thm list -> tactic) -> method ;
+ − 1683
METHOD : (thm list -> tactic) -> method ;
+ − 1684
+ − 1685
SIMPLE_METHOD : tactic -> method ;
+ − 1686
SIMPLE_METHOD' : (int -> tactic) -> method ;
+ − 1687
SIMPLE_METHOD'' : ((int -> tactic) -> tactic) -> (int -> tactic) -> method ;
+ − 1688
+ − 1689
RAW_METHOD_CASES : (thm list -> cases_tactic) -> method ;
+ − 1690
METHOD_CASES : (thm list -> cases_tactic) -> method ;
+ − 1691
\end{verbatim}
+ − 1692
A method is, in its simplest form, a tactic; applying the method is to apply
+ − 1693
the tactic to the current goal state.
+ − 1694
+ − 1695
Applying \texttt{RAW\_METHOD tacf} creates a tactic by applying
+ − 1696
\texttt{tacf} to the current {facts}, and applying that tactic to the
+ − 1697
goal state.
+ − 1698
+ − 1699
\texttt{METHOD} is similar but also first applies
+ − 1700
\texttt{Goal.conjunction\_tac} to all subgoals.
+ − 1701
+ − 1702
\texttt{SIMPLE\_METHOD tac} inserts the facts into all subgoals and then
+ − 1703
applies \texttt{tacf}.
+ − 1704
+ − 1705
\texttt{SIMPLE\_METHOD' tacf} inserts the facts and then
+ − 1706
applies \texttt{tacf} to subgoal 1.
+ − 1707
+ − 1708
\texttt{SIMPLE\_METHOD'' quant tacf} does this for subgoal(s) selected by
+ − 1709
\texttt{quant}, which may be, for example,
+ − 1710
\texttt{ALLGOALS} (all subgoals),
+ − 1711
\texttt{TRYALL} (try all subgoals, failure is OK),
+ − 1712
\texttt{FIRSTGOAL} (try subgoals until it succeeds once),
+ − 1713
\texttt{(fn tacf => tacf 4)} (subgoal 4), etc
16
+ − 1714
(see the \texttt{Tactical} structure, FIXME) %%\cite[Chapter 4]{ref}).
4
+ − 1715
+ − 1716
A method is stored in a theory as indicated by:
+ − 1717
\begin{verbatim}
+ − 1718
Method.add_method :
+ − 1719
(bstring * (src -> Proof.context -> method) * string) -> theory trf ;
+ − 1720
( *
+ − 1721
* )
+ − 1722
\end{verbatim}
+ − 1723
where the first and third arguments are name and description of the method,
+ − 1724
and the second is a function which parses the method input text
+ − 1725
(including the method name, which has necessarily already been parsed).
+ − 1726
+ − 1727
Here, \texttt{xxx} is a function declared in the code for the
+ − 1728
structure \texttt{Method}, but not published in its signature.
+ − 1729
The source file \texttt{src/Pure/Isar/method.ML} shows the use of
+ − 1730
\texttt{Method.add\_method} to add a number of methods.
+ − 1731
+ − 1732
+ − 1733
*}
75
+ − 1734
(*>*)
+ − 1735
end