Looking at the code (grammar.pm) generated by

use Parse::RecDescent;

my $grammar = <<'__EOI__';
parse: <error:FOO!>
__EOI__

Parse::RecDescent->Precompile($grammar, "grammar")
or die("Bad grammar\n");

[download]

reveals (rearranged to avoid forced line breaks)

$_tok = do {
   if (1) {
      do {
         push @{$thisparser->{errors}}, [qq{FOO!},$thisline];
      } unless  $_noactions;
      undef
   } else {
      0
   }
};

[download]

Let's test it:

use Parse::RecDescent;

my $grammar = <<'__EOI__';
parse: {
   # Create error message.
   my $msg = 'FOO!';

   # Create error.
   push(@{$thisparser->{errors}}, [ $msg, $thisline ])
      unless $_noactions;

   # Fail the action.
   undef;
}
__EOI__

my $parser = Parse::RecDescent->new($grammar)
or die("Bad grammar\n");

$parser->parse('');

[download]

Output:

       ERROR (line 1): FOO!

[download]

bingo!

In reply to Re: changing P::RD error message from within an action by ikegami
in thread changing P::RD error message from within an action by cazz

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.