theory NamedThms

imports "../Base"

begin

section {* Accumulate a List of Theorems under a Name *} 

text {*

  {\bf Problem:} 

  Your tool @{text foo} works with special rules, called @{text foo}-rules.

  Users should be able to declare @{text foo}-rules in the theory,

  which are then used in a method.\smallskip

  {\bf Solution:} This can be achieved using named theorem lists.\smallskip

  Named theorem lists can be set up using the code

  *}

ML {*

structure FooRules = NamedThmsFun (

  val name = "foo" 

  val description = "Rules for foo");

*}

(*<*)setup FooRules.setup(*>*)

text {*

  and the command

  @{text [display] "setup FooRules.setup"}

  This code declares a context data slot where the theorems are stored,

  an attribute @{text foo} (with the usual @{text add} and @{text del} options

  for adding and deleting theorems) and an internal ML interface to retrieve and 

  modify the theorems.

  Furthermore, the facts are made available on the user level under the dynamic 

  fact name @{text foo}. For example we can declare three lemmas to be of the kind

  @{text foo} by:

*}

lemma rule1[foo]: "A" sorry

lemma rule2[foo]: "B" sorry

lemma rule3[foo]: "C" sorry

text {* and undeclare the first one by: *}

declare rule1[foo del]

  On the ML-level the rules marked with @{text "foo"} an be retrieved

  using the function @{ML FooRules.get}:

  @{ML_response_fake [display] "FooRules.get @{context}" "[\"?C\",\"?B\"]"}

  \begin{readmore}

  \end{readmore}

 *}

text {*

  (FIXME: maybe add a comment about the case when the theorems 

  to be added need to satisfy certain properties)

*}

end