Fix complaints about escape sequences.

Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2009-08/msg00036.html>.
* src/scan-gram.l (SC_ESCAPED_STRING, SC_ESCAPED_CHARACTER):
For a \0 and similar escape sequences meaning the null
character, report an invalid escape sequence instead of an
invalid null character because the latter does not actually
appear in the user's input.
In all escape sequence complaints, don't escape the initial
backslash, and don't quote when the sequence appears at the end
of the complaint line unless there's whitespace that quotearg
won't escape.
Consistently say "invalid" not "unrecognized".
Consistently prefer "empty character literal" over "extra
characters in character literal" warning for invalid escape
sequences; that is, consistently discard those sequences.
* tests/input.at (Bad escapes in literals): New.

diff --git a/ChangeLog b/ChangeLog
index c0d3607e3db35ee3ea0b65f59fc0c47d2308010b..d1e0bc109508f5c681ddfb0a709a2e7958c30693 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2009-08-19  Joel E. Denny  <jdenny@clemson.edu>
+
+       Fix complaints about escape sequences.
+       Discussed starting at
+       <http://lists.gnu.org/archive/html/bison-patches/2009-08/msg00036.html>.
+       * src/scan-gram.l (SC_ESCAPED_STRING, SC_ESCAPED_CHARACTER):
+       For a \0 and similar escape sequences meaning the null
+       character, report an invalid escape sequence instead of an
+       invalid null character because the latter does not actually
+       appear in the user's input.
+       In all escape sequence complaints, don't escape the initial
+       backslash, and don't quote when the sequence appears at the end
+       of the complaint line unless there's whitespace that quotearg
+       won't escape.
+       Consistently say "invalid" not "unrecognized".
+       Consistently prefer "empty character literal" over "extra
+       characters in character literal" warning for invalid escape
+       sequences; that is, consistently discard those sequences.
+       * tests/input.at (Bad escapes in literals): New.
+
 2009-08-19  Akim Demaille  <demaille@gostai.com>
 
        doc: fixes.

diff --git a/src/scan-gram.l b/src/scan-gram.l
index 7a6d7bfe78546ad6ae0796cd7a9607122d763641..4ed30c6f3162e10b50289130132e7223d4ffdce5 100644 (file)
--- a/src/scan-gram.l
+++ b/src/scan-gram.l
@@ -37,6 +37,7 @@
 #include <src/reader.h>
 #include <src/uniqstr.h>
 
+#include <ctype.h>
 #include <mbswidth.h>
 #include <quote.h>
 
@@ -578,10 +579,9 @@ splice      (\\[ \f\t\v]*\n)*
 {
   \\[0-7]{1,3} {
     unsigned long int c = strtoul (yytext + 1, NULL, 8);
-    if (UCHAR_MAX < c)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (!c || UCHAR_MAX < c)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);
     else
       obstack_1grow (&obstack_for_string, c);
   }
@@ -589,10 +589,9 @@ splice      (\\[ \f\t\v]*\n)*
   \\x[0-9abcdefABCDEF]+ {
     verify (UCHAR_MAX < ULONG_MAX);
     unsigned long int c = strtoul (yytext + 2, NULL, 16);
-    if (UCHAR_MAX < c)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (!c || UCHAR_MAX < c)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);
     else
       obstack_1grow (&obstack_for_string, c);
   }
@@ -610,16 +609,23 @@ splice     (\\[ \f\t\v]*\n)*
 
   \\(u|U[0-9abcdefABCDEF]{4})[0-9abcdefABCDEF]{4} {
     int c = convert_ucn_to_byte (yytext);
-    if (c < 0)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (c <= 0)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);
     else
       obstack_1grow (&obstack_for_string, c);
   }
   \\(.|\n)     {
-    complain_at (*loc, _("unrecognized escape sequence: %s"), quote (yytext));
-    STRING_GROW;
+    char const *p = yytext + 1;
+    char quoted_ws[] = "` '";
+    if (isspace (*p) && isprint (*p))
+      {
+        quoted_ws[1] = *p;
+        p = quoted_ws;
+      }
+    else
+      p = quotearg_style_mem (escape_quoting_style, p, 1);
+    complain_at (*loc, _("invalid character after \\-escape: %s"), p);
   }
 }
 

diff --git a/tests/input.at b/tests/input.at
index 810e7601a6bc6d71b89d7b21ed58f0e4d25d7c88..f91c0fb8070135347134f5ec1bc17f9e08a8e5c5 100644 (file)
--- a/tests/input.at
+++ b/tests/input.at
@@ -1220,3 +1220,46 @@ three.y:4.8-11: missing `'' at end of file
 ]])
 
 AT_CLEANUP
+
+## ------------------------- ##
+## Bad escapes in literals.  ##
+## ------------------------- ##
+
+AT_SETUP([[Bad escapes in literals]])
+
+AT_DATA([input.y],
+[[%%
+start: '\777' '\0' '\xfff' '\x0'
+       '\uffff' '\u0000' '\Uffffffff' '\U00000000'
+       '\ ' '\A';
+]])
+echo 'start: "\T\F\0\1" ;' | tr 'TF01' '\011\014\0\1' >> input.y
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:2.9-12: invalid number after \-escape: 777
+input.y:2.8-13: warning: empty character literal
+input.y:2.16-17: invalid number after \-escape: 0
+input.y:2.15-18: warning: empty character literal
+input.y:2.21-25: invalid number after \-escape: xfff
+input.y:2.20-26: warning: empty character literal
+input.y:2.29-31: invalid number after \-escape: x0
+input.y:2.28-32: warning: empty character literal
+input.y:3.9-14: invalid number after \-escape: uffff
+input.y:3.8-15: warning: empty character literal
+input.y:3.18-23: invalid number after \-escape: u0000
+input.y:3.17-24: warning: empty character literal
+input.y:3.27-36: invalid number after \-escape: Uffffffff
+input.y:3.26-37: warning: empty character literal
+input.y:3.40-49: invalid number after \-escape: U00000000
+input.y:3.39-50: warning: empty character literal
+input.y:4.9-10: invalid character after \-escape: ` '
+input.y:4.8-11: warning: empty character literal
+input.y:4.14-15: invalid character after \-escape: A
+input.y:4.13-16: warning: empty character literal
+input.y:5.9-16: invalid character after \-escape: \t
+input.y:5.17: invalid character after \-escape: \f
+input.y:5.18: invalid character after \-escape: \0
+input.y:5.19: invalid character after \-escape: \001
+]])
+
+AT_CLEANUP