Beefy Boxes and Bandwidth Generously Provided by pair Networks
laziness, impatience, and hubris

Re: Skeleton For Import to Package?

by almut (Canon)
on Jul 28, 2010 at 14:17 UTC ( #851721=note: print w/replies, xml ) Need Help??

in reply to Skeleton For Import to Package?

so, how do I get the arguments

Inspect @_ in the import routine.

sub import { my $pkg = shift; # "cacher" in this case my $dir = $_[0] || "/tmp"; setup_cachehash($dir); ... } sub setup_cachehash { ... }

Replies are listed 'Best First'.
Re^2: Skeleton For Import to Package?
by iaw4 (Monk) on Jul 28, 2010 at 15:14 UTC
    thanks. I just realized that my error comes from another source. How do I force the "import" to be the first executed statement? ... answer below
    package cacher; use strict; use warnings; use warnings FATAL => qw{ uninitialized }; # larry, this should have b +een part of warnings. use base 'Exporter'; our @EXPORT = ("pdfpagenum"); BEGIN { my $saved_pkg_args="undefined"; sub import { print "import args: ".join("|", @_)."\n"; $saved_pkg_args= $_[1]; print "in import, saved args '$saved_pkg_args'\n"; } sub test { print STDERR "in test, you have saved '$saved_pkg_args'\n +"; } print "this should executed after the import: $saved_pkg_args.\n" } 1;
    I guess I should just call everything I want to be main code from the import statement itself. still strange that import() is not the first thing called.
      How do I force the "import" to be the first executed statement?

      You can't (at least not with the desired arguments), because cacher->import(...) is being called after the module has been required — at which point any code of the module outside of subroutines will already have been run. That's how use works...

      Update: it's maybe worth mentioning that import is not being called at all if you say use cacher ();. If that's an issue in your case, you might want to setup %cachehash with a default directory at the time the module is being required. Then, in case import is being called, just re-initialize %cachehash with the directory specified as the argument to use.  Kind of like this:

      sub import { ... setup_cachehash($dir) if $dir; } sub setup_cachehash { ... } setup_cachehash("/tmp"); # default

      (From a performance point of view, doing things twice is of course suboptimal...)

      P.S.: if you use Exporter in the same package, you probably want to explicitly call its import routine with the appropriate arguments (first arg = your package name), because normally the import method will be inherited from Exporter. In other words, Exporter's import will no longer be called (automatically) when you implement import yourself...

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://851721]
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others examining the Monastery: (10)
As of 2018-04-25 17:06 GMT
Find Nodes?
    Voting Booth?