[Commit] mint/src mint-parser.5c,1.1,1.2

[Bart Massey]

Committed by: bart

Update of /local/src/CVS/mint/src
In directory home.keithp.com:/tmp/cvs-serv12947/src

Modified Files:
	mint-parser.5c 
Log Message:
Changed token syntax for lolgram.mnt slightly.
Added convenience routines, reference-passing to mint-parser.5c.



Index: mint-parser.5c
===================================================================
RCS file: /local/src/CVS/mint/src/mint-parser.5c,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -d -r1.1 -r1.2
--- mint-parser.5c	13 Jan 2005 09:24:48 -0000	1.1
+++ mint-parser.5c	16 Jan 2005 07:43:50 -0000	1.2
@@ -43,18 +43,37 @@
 load "lexer_io.5c"
 
 namespace MintParser {
+    /* more friendly syntax error exception: line number and message */
     public exception syntax_error(int, string);
 
-    public ast parse_file(string mntbase, string target) {
+    public &ast parse_file(string mntbase, string target)
+	/* lex and parse a file given the serialized lexer
+	   and parser at the given address */
+    {
 	lexer lex = load_lexer(mntbase + ".mtl");
 	parse_table ptbl = load_parser(mntbase + ".mtp");
 	file f = open(target, "r");
 	try {
-	    ast a = Mint::parse_file(&ptbl, &lex, f);
+	    &ast a = &Mint::parse_file(&ptbl, &lex, f);
 	} catch syntax_error(&lexer_context lc) {
 	    raise syntax_error(lc.line_number, get_token(&lc).lexeme);
 	}
-	return a;
+	return &a;
     }
-}
 
+    public &ast get_nonterminal(&ast a, string path ...)
+	/* Convenience routine: walk down a parse tree to a nonterminal */
+    {
+	for (int i = 0; i < dim(path); i++)
+	    &a = &a.nonterminal.fields[path[i]];
+	return &a;
+    }
+
+    public &token get_terminal(&ast a, string path ...)
+	/* Convenience routine: walk down a parse tree to a terminal */
+    {
+	for (int i = 0; i < dim(path); i++)
+	    &a = &a.nonterminal.fields[path[i]];
+	return &a.terminal;
+    }
+}