Pass a parameter to a callback function

BruceDB has asked for the wisdom of the Perl Monks concerning the following question:

I have some code where I use callbacks to run the appropriate sub. The code works.

 sub run_parser {
  my $parser = shift;
  &{$parser};
}
[download]

However, I need to be able to pass parameters (scalar, array, hash, whatever). What is the correct syntax for passing a parameter (lets say a scalar $url)? Thanks,

Comment on Pass a parameter to a callback function Download Code

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Re: Pass a parameter to a callback function by ikegami (Patriarch) on Oct 15, 2009 at 01:11 UTC
You shouldn't use `&func;` (or `&$func_rec;`) unless you intend to. It doesn't pass "no parameters", it passes the `@_` unlocalised, unchanged. `&$func_rec() # No params &$func_rec(param, ...) # With params $func_rec->() # Same as above, $func_rec->(param, ...) # but easier to read` [download]	[reply] [d/l] [select]
Re: Pass a parameter to a callback function by BruceDB (Novice) on Oct 15, 2009 at 01:04 UTC
I figured it out. I was sending the parameter using: `&{parser}($url);` [download] The correct way should have the parameter in quotes: `&{parser}("$url");` [download]	[reply] [d/l] [select]
Re^2: Pass a parameter to a callback function by ikegami (Patriarch) on Oct 15, 2009 at 01:14 UTC
The quotes creates a copy of the variable after forcing it into a string. You shouldn't ever have to do that. Something is very funky in your parser.	[reply]