The problem is a long story, but the minimal test case is pretty clear. I have a subroutine which needs to know where is was called. For example:

while ( my $value = some_sub() ) {
    # do something
    my $other_value = some_sub();
}

[download]

In the above case, it's pretty easy to disambiguate:

sub some_sub {
    my @caller = caller();
    # now I know where I was called
}

[download]

That assigns the package, filename, and line number to @caller. However, there's a very weird edge case here:

for ( 1 .. 10 ) {
    my ( $foo, $bar ) = ( some_sub(), some_sub() );
    # do stuff
}

[download]

@caller will hold the same value for each of those. I'm overriding a pre-existing interface, so I'm not at liberty to change said interface. Without more information available, is there any way in &some_sub to know which invocation on a line was called? I can't hardcode any knowledge about the structure of calling lines because this may be called in many different places.

Cheers,
Ovid

New address of my CGI Course.

In reply to Where was I called? by Ovid

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.