Re: error: invalid character `' (ASCII 0) near line 164, column 2 (problem avoided)

[Ben Abbott]

On Thursday, December 31, 2009, at 03:17PM, "Ben Abbott" <address@hidden> wrote:
>On Thursday, December 31, 2009, at 01:04PM, "Michael D Godfrey" 
><address@hidden> wrote:
>>
>> Ben,
>> 
>> I just looked on my Linux Fedora 12 system. It uses
>> flex 2.3.5.  So, it appears that the Mac version must be broken
>> in some way that is not just the wrong version.  So, you
>> might try compiling the 2.3.5 version from sourceforge.
>> They also have earlier versions available in case 2.3.5
>> fails.
>> 
>> Michael
>> 
>
>Michael, do you mean "2.5.35"?
>
>Using 2.5.35 from sourceforge, Octave no longer produces the (ASCII 0) errors!
>
>I took a look at Apple's patches to flex. It looks to me like the one below is 
>responsible.
>
>http://www.opensource.apple.com/source/flex/flex-24.1/patches/scanEOF.diff
>
>---------------
>--- flex.skl+orig      2006-12-20 12:29:20.000000000 -0800
>+++ flex.skl   2006-12-20 12:29:32.000000000 -0800
>@@ -1818,7 +1818,7 @@ m4_ifdef( [[M4_YY_USE_LINENO]],
>                               case EOB_ACT_END_OF_FILE:
>                                       {
>                                       if ( yywrap( M4_YY_CALL_ONLY_ARG ) )
>-                                              return EOF;
>+                                              return 0;
> 
>                                       if ( ! 
> YY_G(yy_did_buffer_switch_on_eof) )
>                                               YY_NEW_FILE;
>---------------
>
>Looking at my lex.cc produced using the sourceforge version of flex ...
>
>2834 case 89:
>2835 YY_RULE_SETUP
>2836 #line 1032 "lex.ll"
>2837 {
>2838     LEXER_DEBUG (".");
>2839 
>2840     xunput (octave_text[0], octave_text);
>2841 
>2842     int c = text_yyinput ();
>2843 
>2844     if (c != EOF)
>2845       {
>2846         current_input_column++;
>2847 
>2848         error ("invalid character `%s' (ASCII %d) near line %d, column 
>%d",
>2849                undo_string_escape (static_cast<char> (c)), c,
>2850                input_line_number, current_input_column);
>2851 
>2852         return LEXICAL_ERROR;
>2853       }
>2854     else
>2855       TOK_RETURN (END_OF_INPUT);
>2856   }
>2857         YY_BREAK
>
>When using Apple's flex, I was able to avoid the (ASCII 0) error by commenting 
>out lines 2844-2854. Alternatively, we could modify lex.ll so that line 2844 
>reads something like …
>
>2844     if (! (c == EOF || (c == 0 && ismac ())))
>
>The lines from lex.ll are below. Line 1039 is what needs to be changed.
>
>1032 . {
>1033     LEXER_DEBUG (".");
>1034 
>1035     xunput (yytext[0], yytext);
>1036 
>1037     int c = text_yyinput ();
>1038 
>1039     if (c != EOF)
>1040       {
>1041         current_input_column++;
>1042 
>1043         error ("invalid character `%s' (ASCII %d) near line %d, column 
>%d",
>1044                undo_string_escape (static_cast<char> (c)), c,
>1045                input_line_number, current_input_column);
>1046 
>1047         return LEXICAL_ERROR;
>1048       }
>1049     else
>1050       TOK_RETURN (END_OF_INPUT);
>1051   }
>
>I doubt "ismac()" is available. Forgive my lame attempt at cpp/c++, but would 
>replacing line 1039 of lex.ll with the lines below work?
>
>#if defined (__APPLE__) && defined (__MACH__)
>     if (! (c == EOF || (c == 0 && ismac ())))
>#else /* not MacOS X */
>     if (c != EOF)
>#endif
>
>Ben

Opps, that should have been ...

#if defined (__APPLE__) && defined (__MACH__)
     if (! (c == EOF || c == 0))
#else /* not MacOS X */
     if (c != EOF)
#endif

I tried this change, and it worked for me with the sourceforge flex, I'm 
building with Apple's now. If it works, I'll post a changeset to the list. As I 
don't trust myself with c++, I'd appreciate some feedback.

Ben


Ben