From grdetil@scrc.umanitoba.ca Wed Feb 17 13:42:40 1999
Date: Wed, 17 Feb 1999 15:30:00 -0600 (CST)
From: Gilles Detillieux <grdetil@scrc.umanitoba.ca>
To: htdig3-dev@htdig.org
Cc: htdig3-dev@htdig.org
Subject: Re: [htdig3-dev] Final (?) tar of 3.1.1


> Big sigh!  I just finished building my rpms, and uploaded them to
> ftp://ftp.htdig.org/incoming/, then I discovered a minor glitch in the
> parser error messages.  A query string of "(tool and not bar)" now gives
> the error message:
> 
> 	Expected a search word instead of '!' or 'NOT' instead of ')' 
> 
> The extra instead of ')' seems to happen because the parser code seems to
> keep going, even after it detects an invalid syntax.  Usually, it would
> just replace one error string with another, but my little addition to the
> factor() function just appends to whatever is there.  I'm working on a
> patch for this, but I don't know whether this should hold up the release
> or not.

OK, here's my patch for this, to be applied to the 3.1.1 final release.
Sorry about not catching this sooner.  Now, it only gives a message for
the first error found, and doesn't add extra junk when it shouldn't.
In the process, I managed to tidy things up too.  Please give this a try.

--- ./htsearch/parser.h.errors2	Tue Feb 16 23:03:56 1999
+++ ./htsearch/parser.h	Wed Feb 17 14:58:44 1999
@@ -34,6 +34,7 @@
     void		term(int);
     void		factor(int);
     int			match(int);
+    void		setError(char *);
     void		perform_push();
     void		perform_and(int);
     void		perform_or();
--- ./htsearch/parser.cc.errors2	Tue Feb 16 23:03:56 1999
+++ ./htsearch/parser.cc	Wed Feb 17 15:08:44 1999
@@ -34,8 +34,6 @@
 Parser::checkSyntax(List *tokenList)
 {
     tokens = tokenList;
-    tokens->Start_Get();
-    lookahead = lexan();
     valid = 1;
     fullexpr(0);
     return valid;
@@ -45,19 +43,12 @@
 void
 Parser::fullexpr(int output)
 {
+    tokens->Start_Get();
+    lookahead = lexan();
     expr(output);
-    if (lookahead != DONE)
+    if (valid && lookahead != DONE)
     {
-	valid = 0;
-	error = 0;
-	error << "Expected end of expression instead of '";
-	error << current->word.get() << '\'';
-	switch (lookahead)
-	{
-	case '&':	error << " or 'AND'";	break;
-	case '|':	error << " or 'OR'";	break;
-	case '!':	error << " or 'NOT'";	break;
-	}
+	setError("end of expression");
     }
 }
 
@@ -107,12 +98,9 @@
 	else
 	    break;
     }
-    if (lookahead == WORD)
+    if (valid && lookahead == WORD)
     {
-	valid = 0;
-	error = 0;
-	error << "Expected 'AND' or 'OR' instead of '" << current->word.get();
-	error << '\'';
+	setError("'AND' or 'OR'");
     }
 }
 
@@ -151,9 +139,7 @@
 	}
 	else
 	{
-	    valid = 0;
-	    error = 0;
-	    error << "Expected ')'";
+	    setError("')'");
 	}
     }
     else if (lookahead == WORD)
@@ -166,13 +152,32 @@
     }
     else
     {
-	valid = 0;
-	error = 0;
-	error << "Expected a search word";
+	setError("a search word");
     }
+}
 
-    if (!valid)
+//*****************************************************************************
+int
+Parser::match(int t)
+{
+    if (lookahead == t)
     {
+	lookahead = lexan();
+	return 1;
+    }
+    else
+	return 0;
+}
+
+//*****************************************************************************
+void
+Parser::setError(char *expected)
+{
+    if (valid)
+    {
+	valid = 0;
+	error = 0;
+	error << "Expected " << expected;
 	if (lookahead == DONE || !current)
 	{
 	    error << " at the end";
@@ -192,19 +197,6 @@
 }
 
 //*****************************************************************************
-int
-Parser::match(int t)
-{
-    if (lookahead == t)
-    {
-	lookahead = lexan();
-	return 1;
-    }
-    else
-	return 0;
-}
-
-//*****************************************************************************
 // Perform a lookup of the current word and push the result onto the stack
 //
 void
@@ -409,8 +401,6 @@
 Parser::parse(List *tokenList, ResultList &resultMatches)
 {
     tokens = tokenList;
-    tokens->Start_Get();
-    lookahead = lexan();
     fullexpr(1);
 
     ResultList	*result = (ResultList *) stack.pop();


-- 
Gilles R. Detillieux              E-mail: <grdetil@scrc.umanitoba.ca>
Spinal Cord Research Centre       WWW:    http://www.scrc.umanitoba.ca/~grdetil
Dept. Physiology, U. of Manitoba  Phone:  (204)789-3766
Winnipeg, MB  R3E 3J7  (Canada)   Fax:    (204)789-3930
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