src/Pure/Isar/value_parse.ML

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Isar/value_parse.ML	Fri Jan 02 15:44:32 2009 +0100
@@ -0,0 +1,45 @@
+(*  Title:      Pure/Isar/value_parse.ML
+    Author:     Makarius
+
+Outer syntax parsers for basic ML values.
+*)
+
+signature VALUE_PARSE =
+sig
+  type 'a parser = 'a OuterParse.parser
+  val comma: 'a parser -> 'a parser
+  val equal: 'a parser -> 'a parser
+  val parens: 'a parser -> 'a parser
+  val pair: 'a parser -> 'b parser -> ('a * 'b) parser
+  val triple: 'a parser -> 'b parser -> 'c parser -> ('a * 'b * 'c) parser
+  val properties: Properties.T parser
+end;
+
+structure ValueParse: VALUE_PARSE =
+struct
+
+structure P = OuterParse;
+type 'a parser = 'a P.parser;
+
+
+(* syntax utilities *)
+
+fun comma p = P.$$$ "," |-- P.!!! p;
+fun equal p = P.$$$ "=" |-- P.!!! p;
+fun parens p = P.$$$ "(" |-- P.!!! (p --| P.$$$ ")");
+
+
+(* tuples *)
+
+val unit = parens (Scan.succeed ());
+fun pair p1 p2 = parens (p1 -- comma p2);
+fun triple p1 p2 p3 = parens (p1 -- comma p2 -- comma p3) >> P.triple1;
+
+
+(* lists *)
+
+fun list p = parens (P.enum "," p);
+val properties = list (P.string -- equal P.string);
+
+end;
+