Re: expression debugging

Re: expression debugging

[David Taylor]

    Date: Wed, 7 Feb 2001 19:06:47 -0800
    From: Doug Evans <dje@transmeta.com>

    When's the last time anyone did `set debug expression 1'?
    [just curious how much bitrot I should expect]

It works.  I've used it from the command line version of gdb within
the past month.  It could definitely be improved, but it works.

Problems with it when using the GUI (namely, the output not showing
up at all) was my motivation for creating and posting the patch:

http://sources.redhat.com/ml/insight/2001-q1/msg00006.html
http://sources.redhat.com/ml/gdb-patches/2001-01/msg00001.html

[Which, sadly, never got applied because I was told that rather than
fix a bug in this area, I should rewrite the existing code...  And,
frankly, right now I don't have the time for that.]

    Also, aren't dump_prefix_expression/dump_postfix_expression misnamed?
    [should be the other way around]

Probably.  But, even then the names wouldn't be completely correct.

I don't know who created the original names.  I just try to think of
the names as "pre" (before) 'fixing the expression' and "post" (after)
'fixing the expression' and worry about other things instead.  (Where
'fixing the expression' refers to putting the expression into a form
that GDB likes.)

expression debugging

[Doug Evans]

When's the last time anyone did `set debug expression 1'?
[just curious how much bitrot I should expect]

Also, aren't dump_prefix_expression/dump_postfix_expression misnamed?
[should be the other way around]

parse.c:parse_exp_1:
  /* Convert expression from postfix form as generated by yacc
     parser, to a prefix form. */

  if (expressiondebug)
    dump_prefix_expression (expout, gdb_stdlog,
			    "before conversion to prefix form");

  prefixify_expression (expout);

  if (expressiondebug)
    dump_postfix_expression (expout, gdb_stdlog,
			     "after conversion to prefix form");