* generic/tclCompExpr.c: More commentary.

        * tests/parseExpr.test:         Several tests of syntax error messages
        to check that when expression substrings are truncated they leave
        visible the context relevant to the reported error.

3 files changed, 126 insertions, 7 deletions

diff --git a/ChangeLog b/ChangeLog
index 9e8012b..7057eb3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2007-07-15  Don Porter  <dgp@users.sourceforge.net>
+
+	* generic/tclCompExpr.c:	More commentary.
+	* tests/parseExpr.test:		Several tests of syntax error messages
+	to check that when expression substrings are truncated they leave
+	visible the context relevant to the reported error.
+
 2007-07-12  Don Porter  <dgp@users.sourceforge.net>
 
 	* generic/tclCompExpr.c:	Factored out, corrected, and commented
diff --git a/generic/tclCompExpr.c b/generic/tclCompExpr.c
index da9007f..bab56f5 100644
--- a/generic/tclCompExpr.c
+++ b/generic/tclCompExpr.c
@@ -12,7 +12,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCompExpr.c,v 1.68 2007/07/12 22:13:12 dgp Exp $
+ * RCS: @(#) $Id: tclCompExpr.c,v 1.69 2007/07/16 19:50:46 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -514,6 +514,7 @@ ParseExpr(
 	nodes->precedence = prec[lexeme];
 	nodes->left = OT_NONE;
 	nodes->right = OT_NONE;
+	/* TODO: explain. */
 	nodes->parent = -1;
 	nodesUsed++;
     }
@@ -849,19 +850,32 @@ ParseExpr(
 	} /* case LEAF */
 
 	case UNARY:
+	    /*
+	     * A unary operator appearing just after something that's not an
+	     * operator is a syntax error -- something trying to be the left
+	     * operand of an operator that doesn't take one.
+	     */
 	    if (NotOperator(lastParsed)) {
 		msg = Tcl_ObjPrintf("missing operator at %s", mark);
 		scanned = 0;
 		insertMark = 1;
 		code = TCL_ERROR;
+		/* Escape the parse loop to report the syntax error. */
 		continue;
 	    }
-	    lastParsed = nodesUsed;
-	    nodePtr->lexeme = lexeme;
-	    nodePtr->precedence = prec[lexeme];
-	    nodePtr->left = OT_NONE;
-	    nodePtr->right = OT_NONE;
+	    /* Create an OpNode for the unary operator */
+	    nodePtr->lexeme = lexeme;		/* Remember the operator... */
+	    nodePtr->precedence = prec[lexeme];	/* ... and its precedence. */
+	    nodePtr->left = OT_NONE;		/* No left operand */
+	    nodePtr->right = OT_NONE;		/* Right operand not
+						 * yet known. */
+	    /* TODO: explain */
 	    nodePtr->parent = nodePtr - nodes - 1;
+	    /*
+	     * Remember this unary operator as the last thing parsed for
+	     * the next pass through the loop.
+	     */
+	    lastParsed = nodesUsed;
 	    nodesUsed++;
 	    break;
 
@@ -869,6 +883,11 @@ ParseExpr(
 	    OpNode *otherPtr = NULL;
 	    unsigned char precedence = prec[lexeme];
 
+	    /*
+	     * A binary operand appearing just after another operator is a
+	     * syntax error -- one of the two operators is missing an operand.
+	     */
+
 	    if (IsOperator(lastParsed)) {
 		if ((lexeme == CLOSE_PAREN)
 			&& (nodePtr[-1].lexeme == OPEN_PAREN)) {
@@ -879,6 +898,7 @@ ParseExpr(
 			 */
 
 			scanned = 0;
+			/* TODO: explain */
 			lastParsed = OT_EMPTY;
 			nodePtr[-1].left--;
 			break;
@@ -923,6 +943,7 @@ ParseExpr(
 		continue;
 	    }
 
+	    /* TODO: explain */
 	    if (lastParsed == OT_NONE) {
 		otherPtr = nodes + lastOpen - 1;
 		lastParsed = lastOpen;
diff --git a/tests/parseExpr.test b/tests/parseExpr.test
index d2261bf..f89727d 100644
--- a/tests/parseExpr.test
+++ b/tests/parseExpr.test
@@ -8,7 +8,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
-# RCS: @(#) $Id: parseExpr.test,v 1.25 2006/08/23 21:31:55 dgp Exp $
+# RCS: @(#) $Id: parseExpr.test,v 1.26 2007/07/16 19:50:46 dgp Exp $
 
 if {[lsearch [namespace children] ::tcltest] == -1} {
     package require tcltest 2
@@ -911,6 +911,97 @@ in expression "...%s" @ 0"
     (parsing expression ""%s...")
     invoked from within
 "expr [format {"%%s" @ 0} [string repeat \u00a7 25]]"} [string repeat \u00a7 10] [string repeat \u00a7 10]]
+test parseExpr-21.42 {error message} -body {
+    expr {123456789012345678901234567890*"abcdefghijklmnopqrstuvwxyz}
+} -returnCodes error -result {missing "
+in expression "...012345678901234567890*"abcdefghijklmnopqrstuv..."}
+test parseExpr-21.43 {error message} -body {
+    expr "123456789012345678901234567890*\"foobar\$\{abcdefghijklmnopqrstuvwxyz\""
+} -returnCodes error -result "missing close-brace for variable name
+in expression \"...8901234567890*\"foobar\$\{abcdefghijklmnopqrstuv...\""
+test parseExpr-21.44 {error message} -body {
+    expr {123456789012345678901234567890*"foo$bar(abcdefghijklmnopqrstuvwxyz"}
+} -returnCodes error -result {missing )
+in expression "...8901234567890*"foo$bar(abcdefghijklmnopqrstuv..."}
+test parseExpr-21.45 {error message} -body {
+    expr {123456789012345678901234567890*"foo$bar([{}abcdefghijklmnopqrstuvwxyz])"}
+} -returnCodes error -result {extra characters after close-brace
+in expression "...234567890*"foo$bar([{}abcdefghijklmnopqrstuv..."}
+test parseExpr-21.46 {error message} -body {
+    expr {123456789012345678901234567890*"foo$bar([""abcdefghijklmnopqrstuvwxyz])"}
+} -returnCodes error -result {extra characters after close-quote
+in expression "...234567890*"foo$bar([""abcdefghijklmnopqrstuv..."}
+test parseExpr-21.47 {error message} -body {
+    expr {123456789012345678901234567890*"foo$bar([abcdefghijklmnopqrstuvwxyz)"}
+} -returnCodes error -result {missing close-bracket
+in expression "...901234567890*"foo$bar([abcdefghijklmnopqrstuv..."}
+test parseExpr-21.48 {error message} -body {
+    expr "123456789012345678901234567890*\"foo\$bar(\[\{abcdefghijklmnopqrstuvwxyz])\""
+} -returnCodes error -result "missing close-brace
+in expression \"...01234567890*\"foo\$bar(\[\{abcdefghijklmnopqrstuv...\""
+
+test parseExpr-21.49 {error message} -body {
+    expr "123456789012345678901234567890*\{abcdefghijklmnopqrstuvwxyz"
+} -returnCodes error -result "missing close-brace
+in expression \"...012345678901234567890*\{abcdefghijklmnopqrstuv...\""
+
+test parseExpr-21.50 {error message} -body {
+    expr {123456789012345678901234567890*$foo(["abcdefghijklmnopqrstuvwxyz])}
+} -returnCodes error -result {missing "
+in expression "...678901234567890*$foo(["abcdefghijklmnopqrstuv..."}
+test parseExpr-21.51 {error message} -body {
+    expr "123456789012345678901234567890*\$\{abcdefghijklmnopqrstuvwxyz"
+} -returnCodes error -result "missing close-brace for variable name
+in expression \"...12345678901234567890*\$\{abcdefghijklmnopqrstuv...\""
+test parseExpr-21.52 {error message} -body {
+    expr {123456789012345678901234567890*$bar(abcdefghijklmnopqrstuvwxyz}
+} -returnCodes error -result {missing )
+in expression "...45678901234567890*$bar(abcdefghijklmnopqrstuv..."}
+test parseExpr-21.53 {error message} -body {
+    expr {123456789012345678901234567890*$bar([{}abcdefghijklmnopqrstuvwxyz])"}
+} -returnCodes error -result {extra characters after close-brace
+in expression "...8901234567890*$bar([{}abcdefghijklmnopqrstuv..."}
+test parseExpr-21.54 {error message} -body {
+    expr {123456789012345678901234567890*$bar([""abcdefghijklmnopqrstuvwxyz])"}
+} -returnCodes error -result {extra characters after close-quote
+in expression "...8901234567890*$bar([""abcdefghijklmnopqrstuv..."}
+test parseExpr-21.55 {error message} -body {
+    expr {123456789012345678901234567890*$bar([abcdefghijklmnopqrstuvwxyz)"}
+} -returnCodes error -result {missing close-bracket
+in expression "...5678901234567890*$bar([abcdefghijklmnopqrstuv..."}
+test parseExpr-21.56 {error message} -body {
+    expr "123456789012345678901234567890*\$bar(\[\{abcdefghijklmnopqrstuvwxyz])"
+} -returnCodes error -result "missing close-brace
+in expression \"...678901234567890*\$bar(\[\{abcdefghijklmnopqrstuv...\""
+
+test parseExpr-21.57 {error message} -body {
+    expr {123456789012345678901234567890*["abcdefghijklmnopqrstuvwxyz]}
+} -returnCodes error -result {missing "
+in expression "...12345678901234567890*["abcdefghijklmnopqrstuv..."}
+test parseExpr-21.58 {error message} -body {
+    expr "123456789012345678901234567890*\[\$\{abcdefghijklmnopqrstuvwxyz]"
+} -returnCodes error -result "missing close-brace for variable name
+in expression \"...2345678901234567890*\[\$\{abcdefghijklmnopqrstuv...\""
+test parseExpr-21.59 {error message} -body {
+    expr {123456789012345678901234567890*[$bar(abcdefghijklmnopqrstuvwxyz]}
+} -returnCodes error -result {missing )
+in expression "...5678901234567890*[$bar(abcdefghijklmnopqrstuv..."}
+test parseExpr-21.60 {error message} -body {
+    expr {123456789012345678901234567890*[{}abcdefghijklmnopqrstuvwxyz]"}
+} -returnCodes error -result {extra characters after close-brace
+in expression "...345678901234567890*[{}abcdefghijklmnopqrstuv..."}
+test parseExpr-21.61 {error message} -body {
+    expr {123456789012345678901234567890*[""abcdefghijklmnopqrstuvwxyz]"}
+} -returnCodes error -result {extra characters after close-quote
+in expression "...345678901234567890*[""abcdefghijklmnopqrstuv..."}
+test parseExpr-21.62 {error message} -body {
+    expr {123456789012345678901234567890*[abcdefghijklmnopqrstuvwxyz"}
+} -returnCodes error -result {missing close-bracket
+in expression "...012345678901234567890*[abcdefghijklmnopqrstuv..."}
+test parseExpr-21.63 {error message} -body {
+    expr "123456789012345678901234567890*\[\{abcdefghijklmnopqrstuvwxyz]"
+} -returnCodes error -result "missing close-brace
+in expression \"...12345678901234567890*\[\{abcdefghijklmnopqrstuv...\""
 
 # cleanup
 ::tcltest::cleanupTests