From bug-octave-request at bevo dot che dot wisc dot edu Thu Nov 21 13:36:30 2002
Subject: 'clear' command and % comments at end of line -- behavior changes  from 2.1.36 to 2.1.39
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Peter Van Wieren <Peter dot VanWieren at avlna dot com>
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Thu, 21 Nov 2002 13:36:15 -0600

On 21-Nov-2002, Peter Van Wieren <Peter dot VanWieren at avlna dot com> wrote:

| In debugging a octave '.m' script, I have found that when using 'clear' 
| octave no longer ignores comments at the end of a line denoted by the 
| '%' character.  Was this intended ?.  As of version 2.1.36 octave 
| ignores the comment, in 2.1.39 it does not - thus the 'delete variables' 
| comment unexpectedly deletes all variables in memory.
| 
| 
| For example, below I have run the following four lines in 2.1.36 , and 
| 2.1.39
| x = y = z = 1 ;
| whos -v
| clear x y % delete variables
| whos -v

Here is a patch.

The only downside that I can see if that you will no longer be able to
write

  help #

or

  help %

and commands like

  cd #foo

or

  ls %file

will no longer work.  OTOH, you can always use forms like

  cd ("#foo")

or

  ls "%file"

if this is a problem.

jwe



src/ChangeLog:

2002-11-21  John W. Eaton  <jwe at bevo dot che dot wisc dot edu>
 
	* lex.l (<TEXT_FCN>): If yytext begins with # or %, don't
	recognize it as a string.


Index: src/lex.l
===================================================================
RCS file: /usr/local/cvsroot/octave/src/lex.l,v
retrieving revision 1.188
diff -u -r1.188 lex.l
--- src/lex.l	19 Nov 2002 00:33:40 -0000	1.188
+++ src/lex.l	21 Nov 2002 19:31:53 -0000
 at @ -267,7 +267,7 @@
     return handle_string (yytext[0], true);
   }
 
-<TEXT_FCN>[^ \t\n\;\,\"\'][^ \t\n\;\,]*{S}* {
+<TEXT_FCN>[^#% \t\n\;\,\"\'][^ \t\n\;\,]*{S}* {
     std::string tok = strip_trailing_whitespace (yytext);
     TOK_PUSH_AND_RETURN (tok, STRING);
   }



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