Re: is it possible to access eval() counter?

There is no way I know of to (re)set the eval counter, but the usual trick I use to associate evals with the evalled code is to embed a #line comment in your eval() string:

perl -le "eval q!print $^O! for 1..10; eval qq!#line 99 foo.cfg\ndie!;
+print $@"
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gives

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Died at foo.cfg line 99.
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Re^2: is it possible to access eval() counter? (new#line) by tye (Sage) on Jun 30, 2006 at 18:11 UTC
Note that in older versions of Perl you'll need a newline in front of the `#line` directive. Note also that you can make the line number and file name actually match where the eval'd code is. For example, Algorithm::Loops' t/assert.t evals a bunch of code after __END__ but makes any fatal errors report the correct line number via: `# ... my $lineNum; sub SetLineNum { $lineNum= 1+(caller(0))[2]; } while( <DATA> ) { $lineNum++; # ... eval "\n#line $lineNum $0\n$_\n; 1" or die $@; # ... } # ... BEGIN { SetLineNum } __END__ # ...` [download] More typical tricks just use `__LINE__` (plus a constant) and `__FILE__`: `my $file= '"' . __FILE__ . '"'; eval join " ", "\n#line", 1+__LINE__, $file, "\n", <<END, "; 1" or die + $@; ... END` [download] Though, you might want to do a bit extra work if you are on an operating system that allows obnoxious things like file names that contain double quotes. - tye	[reply] [d/l] [select]

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Re^2: is it possible to access eval() counter? (new#line)
by tye (Sage) on Jun 30, 2006 at 18:11 UTC

Note that in older versions of Perl you'll need a newline in front of the #line directive.

Note also that you can make the line number and file name actually match where the eval'd code is. For example, Algorithm::Loops' t/assert.t evals a bunch of code after __END__ but makes any fatal errors report the correct line number via:

# ...
my $lineNum;
sub SetLineNum { $lineNum= 1+(caller(0))[2]; }
while(  <DATA>  ) {
    $lineNum++;
# ...
        eval "\n#line $lineNum $0\n$_\n; 1"
          or  die $@;
# ...
}
# ...

BEGIN { SetLineNum }
__END__
# ...
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More typical tricks just use __LINE__ (plus a constant) and __FILE__:

my $file= '"' . __FILE__ . '"';
eval join " ", "\n#line", 1+__LINE__, $file, "\n", <<END, "; 1" or die
+ $@;
...
END
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Though, you might want to do a bit extra work if you are on an operating system that allows obnoxious things like file names that contain double quotes.

- tye

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