[vox-tech] subroutine arguments with PERL

Wes Hardaker wjhns156 at hardakers.net
Wed Dec 1 07:59:42 PST 2010


>>>>> On Tue, 30 Nov 2010 11:53:51 -0800, Matthew Van Gundy <matt-lugod at shekinahstudios.com> said:

MVG> If you put parenthesis after the subroutine name, you are telling Perl 
MVG> to check the type and number of arguments.  E.g. sub noargs() { }, sub 
MVG> onescalar($) { }, etc.

And it happens at, um, "compile time" too (perl is somewhere between
interpreted and compiled IMHO).

  sub foo($$$$$) {
     my ($stat_ref, $record_number, $prev_line, $line, $line_number) = @_;
     # do stuff
  }

  print "hi\n";
  foo('one');

outputs:
  Not enough arguments for main::foo at foo.pl line 7, near "'one')"
  Execution of foo.pl aborted due to compilation errors.

Note that "hi" isn't in the output because the syntax mistake is caught
before it's run.  Unlike if you leave out the $s and check the arguments
within the function itself.
-- 
Wes Hardaker                                     
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