Produce friendlier errors messages for malformed character

literals and when the parser hits an unexpected EOF.  Also,
disallow newlines in character literals.

R=gri
APPROVED=gri
DELTA=23  (15 added, 1 deleted, 7 changed)
OCL=31790
CL=31797

diff --git a/src/pkg/go/scanner/scanner.go b/src/pkg/go/scanner/scanner.go
index 3a2d98514435ba422b491961939b1d6d548c4dec..2d5e2a83f75047f023ff81516f2600ba97500b38 100644 (file)
--- a/src/pkg/go/scanner/scanner.go
+++ b/src/pkg/go/scanner/scanner.go
@@ -96,6 +96,7 @@ func (S *Scanner) Init(filename string, src []byte, err ErrorHandler, mode uint)
 func charString(ch int) string {
        var s string;
        switch ch {
+       case -1: return `EOF`;
        case '\a': s = `\a`;
        case '\b': s = `\b`;
        case '\f': s = `\f`;
@@ -306,16 +307,29 @@ func (S *Scanner) scanEscape(quote int) {
 }
 
 
-func (S *Scanner) scanChar() {
+func (S *Scanner) scanChar(pos token.Position) {
        // '\'' already consumed
 
-       ch := S.ch;
-       S.next();
-       if ch == '\\' {
-               S.scanEscape('\'');
+       n := 0;
+       for S.ch != '\'' {
+               ch := S.ch;
+               n++;
+               S.next();
+               if ch == '\n' || ch < 0 {
+                       S.error(pos, "character literal not terminated");
+                       n = 1;
+                       break;
+               }
+               if ch == '\\' {
+                       S.scanEscape('\'');
+               }
        }
 
-       S.expect('\'');
+       S.next();
+
+       if n != 1 {
+               S.error(pos, "illegal character literal");
+       }
 }
 
 
@@ -431,7 +445,7 @@ scan_again:
                switch ch {
                case -1  : tok = token.EOF;
                case '"' : tok = token.STRING; S.scanString(pos);
-               case '\'': tok = token.CHAR; S.scanChar();
+               case '\'': tok = token.CHAR; S.scanChar(pos);
                case '`' : tok = token.STRING; S.scanRawString(pos);
                case ':' : tok = S.switch2(token.COLON, token.DEFINE);
                case '.' :