afl-material: comparison progs/funt.scala

equal deleted inserted replaced

-:f5214da1976e
+:8067d0a8ba04
 case List(t) => t
 case _ => { println ("Parse Error\n") ; sys.exit(-1) }
 }
 }
+// convenience for matching later on
+case class ~[+A, +B](_1: A, _2: B)
 class SeqParser[I, T, S](p: => Parser[I, T],
-q: => Parser[I, S])(implicit ev: I => Seq[_]) extends Parser[I, (T, S)] {
+q: => Parser[I, S])(implicit ev: I => Seq[_]) extends Parser[I, ~[T, S]] {
 def parse(sb: I) =
 for ((head1, tail1) <- p.parse(sb);
-(head2, tail2) <- q.parse(tail1)) yield ((head1, head2), tail2)
+(head2, tail2) <- q.parse(tail1)) yield (new ~(head1, head2), tail2)
 }
 class AltParser[I, T](p: => Parser[I, T],
 q: => Parser[I, T])(implicit ev: I => Seq[_]) extends Parser[I, T] {
 def parse(sb: I) = p.parse(sb) ++ q.parse(sb)
 def ~[S] (q : => Parser[I, S]) = new SeqParser[I, T, S](p, q)
 }
 def ListParser[I, T, S](p: => Parser[I, T],
 q: => Parser[I, S])(implicit ev: I => Seq[_]): Parser[I, List[T]] = {
-(p ~ q ~ ListParser(p, q)) ==> { case ((x, y), z) => x :: z : List[T] } ||
+(p ~ q ~ ListParser(p, q)) ==> { case x ~ _ ~ z => x :: z : List[T] } ||
 (p ==> ((s) => List(s)))
 }
 case class TokParser(tok: Token) extends Parser[List[Token], Token] {
 def parse(ts: List[Token]) = ts match {
 // Grammar Rules for Fun
 // arithmetic expressions
 lazy val Exp: Parser[List[Token], Exp] =
 (T_KWD("if") ~ BExp ~ T_KWD("then") ~ Exp ~ T_KWD("else") ~ Exp) ==>
-{ case (((((x, y), z), u), v), w) => If(y, u, w): Exp } ||
+{ case _ ~ y ~ _ ~ u ~ _ ~ w => If(y, u, w): Exp } ||
-(M ~ T_SEMI ~ Exp) ==> { case ((x, y), z) => Sequence(x, z): Exp } || M
+(M ~ T_SEMI ~ Exp) ==> { case x ~ _ ~ z => Sequence(x, z): Exp } || M
 lazy val M: Parser[List[Token], Exp] =
-(T_KWD("write") ~ L) ==> { case (x, y) => Write(y): Exp } || L
+(T_KWD("write") ~ L) ==> { case _ ~ y => Write(y): Exp } || L
 lazy val L: Parser[List[Token], Exp] =
-(T ~ T_OP("+") ~ Exp) ==> { case ((x, y), z) => Aop("+", x, z): Exp } ||
+(T ~ T_OP("+") ~ Exp) ==> { case x ~ _ ~ z => Aop("+", x, z): Exp } ||
-(T ~ T_OP("-") ~ Exp) ==> { case ((x, y), z) => Aop("-", x, z): Exp } || T
+(T ~ T_OP("-") ~ Exp) ==> { case x ~ _ ~ z => Aop("-", x, z): Exp } || T
 lazy val T: Parser[List[Token], Exp] =
-(F ~ T_OP("*") ~ T) ==> { case ((x, y), z) => Aop("*", x, z): Exp } ||
+(F ~ T_OP("*") ~ T) ==> { case x ~ _ ~ z => Aop("*", x, z): Exp } ||
-(F ~ T_OP("/") ~ T) ==> { case ((x, y), z) => Aop("/", x, z): Exp } ||
+(F ~ T_OP("/") ~ T) ==> { case x ~ _ ~ z => Aop("/", x, z): Exp } ||
-(F ~ T_OP("%") ~ T) ==> { case ((x, y), z) => Aop("%", x, z): Exp } || F
+(F ~ T_OP("%") ~ T) ==> { case x ~ _ ~ z => Aop("%", x, z): Exp } || F
 lazy val F: Parser[List[Token], Exp] =
 (IdParser ~ T_LPAREN ~ ListParser(Exp, T_COMMA) ~ T_RPAREN) ==>
-{ case (((x, y), z), w) => Call(x, z): Exp } ||
+{ case x ~ _ ~ z ~ _ => Call(x, z): Exp } ||
-(T_LPAREN ~ Exp ~ T_RPAREN) ==> { case ((x, y), z) => y: Exp } ||
+(T_LPAREN ~ Exp ~ T_RPAREN) ==> { case _ ~ y ~ _ => y: Exp } ||
 IdParser ==> { case x => Var(x): Exp } ||
 NumParser ==> { case x => Num(x): Exp }
 // boolean expressions
 lazy val BExp: Parser[List[Token], BExp] =
-(Exp ~ T_OP("==") ~ Exp) ==> { case ((x, y), z) => Bop("==", x, z): BExp } ||
+(Exp ~ T_OP("==") ~ Exp) ==> { case x ~ _ ~ z => Bop("==", x, z): BExp } ||
-(Exp ~ T_OP("!=") ~ Exp) ==> { case ((x, y), z) => Bop("!=", x, z): BExp } ||
+(Exp ~ T_OP("!=") ~ Exp) ==> { case x ~ _ ~ z => Bop("!=", x, z): BExp } ||
-(Exp ~ T_OP("<") ~ Exp) ==> { case ((x, y), z) => Bop("<", x, z): BExp } ||
+(Exp ~ T_OP("<") ~ Exp) ==> { case x ~ _ ~ z => Bop("<", x, z): BExp } ||
-(Exp ~ T_OP(">") ~ Exp) ==> { case ((x, y), z) => Bop("<", z, x): BExp } ||
+(Exp ~ T_OP(">") ~ Exp) ==> { case x ~ _ ~ z => Bop("<", z, x): BExp } ||
-(Exp ~ T_OP("<=") ~ Exp) ==> { case ((x, y), z) => Bop("<=", x, z): BExp } ||
+(Exp ~ T_OP("<=") ~ Exp) ==> { case x ~ _ ~ z => Bop("<=", x, z): BExp } ||
-(Exp ~ T_OP("=>") ~ Exp) ==> { case ((x, y), z) => Bop("<=", z, x): BExp }
+(Exp ~ T_OP("=>") ~ Exp) ==> { case x ~ _ ~ z => Bop("<=", z, x): BExp }
 lazy val Defn: Parser[List[Token], Decl] =
 (T_KWD("def") ~ IdParser ~ T_LPAREN ~ ListParser(IdParser, T_COMMA) ~ T_RPAREN ~ T_OP("=") ~ Exp) ==>
-{ case ((((((x, y), z), w), u), v), r) => Def(y, w, r): Decl }
+{ case x ~ y ~ z ~ w ~ u ~ v ~ r => Def(y, w, r): Decl }
 lazy val Prog: Parser[List[Token], List[Decl]] =
-(Defn ~ T_SEMI ~ Prog) ==> { case ((x, y), z) => x :: z : List[Decl] } ||
+(Defn ~ T_SEMI ~ Prog) ==> { case x ~ _ ~ z => x :: z : List[Decl] } ||
 (Exp ==> ((s) => List(Main(s)) : List[Decl]))
 // compiler - built-in functions
 // copied from http://www.ceng.metu.edu.tr/courses/ceng444/link/jvm-cpm.html
 //examples
 compile_run("defs")
 compile_run("fact")
-// a problem with the parser
-/*
-val text = "(((((1)))))"
-val tokens = tokenise(text)
-println(tokens)
-val ast = Prog.parse_single(tokens)
-println(ast)
-Exp.parse_single(tokens)
-val text = "((((1))))"
-val tokens = tokenise(text)
-println(tokens)
-Exp.parse(tokens)
-*/

changeset 628	8067d0a8ba04
parent 626	2d91b2107656
child 695	484b74bc057e