Builtin function and reference

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

Hi fellow monks!

Say for the sake of convenience I want to write a script that "symbolic-referencely" wraps Perl's built-in functions like this: &{$ARGV[0]};

Then I can call the script like this: $ ./wrapper chr 128

But it keeps getting me errors like this:
Undefined subroutine &main::chr called at ./wrapper line n.

I know there's such a node: "How do I get a reference to a builtin function?". But please...is there some black magic available that can get me there? I'll appreciate your kindness of sharing your deepest knowledge of Perl.

Ta!

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Re: Builtin function and reference by NetWallah (Canon) on Sep 01, 2011 at 05:03 UTC
As mentioned in your referenced node on "How do I get a reference to a builtin function?", you cant. Here are alternatives: Wrap the function: `>perl -e "my %f=(chr=>sub{chr(shift)}); print $f{$ARGV[0]}->($ARGV[1] +)" chr 35 # >perl -e "my %f=(chr=>sub{chr(shift)}); print $f{$ARGV[0]}->($ARGV[1] +)" chr 36 $` [download] Use eval (more general, but potentially unsafe): `>perl -e "print eval qq\|@ARGV\|" sqrt 2 1.4142135623731 >perl -e "print eval qq\|@ARGV\|" chr 128 Ç` [download] "XML is like violence: if it doesn't solve your problem, use more."	[reply] [d/l] [select]
Re: Builtin function and reference by kcott (Archbishop) on Sep 01, 2011 at 05:02 UTC
You've provided no code nor any context. I'll take a stab and suggest the black magic you're after is eval. `$ perl -Mstrict -wE 'say eval qq{@ARGV}' chr 128 €` [download] Please read How do I post a question effectively?. A better question will get you a better answer. -- Ken	[reply] [d/l]
Re: Builtin function and reference by ikegami (Patriarch) on Sep 01, 2011 at 05:44 UTC
`chr` is an operator, not a subroutine, and thus doesn't exist in the symbol table, and thus won't be found by a symbolic reference.	[reply] [d/l]
Re: Builtin function and reference by pid (Monk) on Sep 01, 2011 at 05:44 UTC
Thanks for all the helpful answers. Thanks ikegami for pointing out the difference. I didn't post my code because it's just a single line: `&{$ARGV[0]}($ARV[1]);`. I think `eval` is the answer to my question. And thanks again, everybody.	[reply] [d/l] [select]