Re^2: Skeleton For Import to Package?

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;
[download]

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.

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Re^3: Skeleton For Import to Package? by almut (Canon) on Jul 28, 2010 at 15:21 UTC
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 `require`d. 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` [download] (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...	[reply] [d/l] [select]

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Re^3: Skeleton For Import to Package?
by almut (Canon) on Jul 28, 2010 at 15:21 UTC

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
[download]

(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...

[reply]
[d/l]
[select]