src/Pure/Isar/outer_parse.scala

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Isar/outer_parse.scala	Tue Dec 22 15:00:43 2009 +0100
@@ -0,0 +1,52 @@
+/*  Title:      Pure/Isar/outer_parse.scala
+    Author:     Makarius
+
+Generic parsers for Isabelle/Isar outer syntax.
+*/
+
+package isabelle
+
+import scala.util.parsing.combinator.Parsers
+
+
+object Outer_Parse
+{
+  trait Parser extends Parsers
+  {
+    type Elem = Outer_Lex.Token
+
+
+    /* basic parsers */
+
+    def token(s: String, pred: Elem => Boolean): Parser[Elem] = new Parser[Elem]
+    {
+      def apply(in: Input) =
+      {
+        if (in.atEnd) Failure(s + " expected (past end-of-file!)", in)
+        else {
+          val token = in.first
+          if (pred(token)) Success(token, in.rest)
+          else
+            token.text match {
+              case (txt, "") =>
+                Failure(s + " expected,\nbut " + txt + " was found", in)
+              case (txt1, txt2) =>
+                Failure(s + " expected,\nbut " + txt1 + " was found:\n" + txt2, in)
+            }
+        }
+      }
+    }
+
+    def not_eof: Parser[Elem] = token("input token", _ => true)
+
+    def keyword(name: String): Parser[Elem] =
+      token(Outer_Lex.Token_Kind.KEYWORD.toString + " \"" + name + "\"",
+        tok => tok.kind == Outer_Lex.Token_Kind.KEYWORD && tok.content == name)
+
+    def name: Parser[Elem] = token("name declaration", _.is_name)
+    def xname: Parser[Elem] = token("name reference", _.is_xname)
+    def text: Parser[Elem] = token("text", _.is_text)
+    def path: Parser[Elem] = token("file name/path specification", _.is_name)
+  }
+}
+