Re^3: How to determine absolute path of current Perl file?

hello, this i was used to do in the script perspective:


my $origin = File::Spec->file_name_is_absolute($0) ? $0 : File::Spec->
+rel2abs($0) ;
my ($drive,$directories,$file) = File::Spec->splitpath( $origin );
my $path = File::Spec->catdir($drive,$directories);
################ check starting path
my $current = File::Spec->rel2abs('.');
if ($current ne $path)  {
        (chdir $path and print "OK chdir to $path\n")|| die "FATAL una
+ble to change directory to '$path'.";
}
[download]

But if now i understand, you want in a module.pm get the absolute path of the script.pl that used it.

If so you can have in the module a BEGIN block that executes before any attempt for (user's) script to change directory. If in the script there is a chdir in a BEGIN block before loading your module.. you are lost.

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

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Re^4: How to determine absolute path of current Perl file? by RonW (Parson) on Feb 29, 2016 at 21:11 UTC
Just FYI, in a module "included" by `use`, executable statements in "file scope" are being run inside a begin block. From the documentation for use, `use Module LIST;` is the same as: `BEGIN { require Module; Module->import( LIST ); }` The reason for using a `BEGIN` block in a module to execute some code before the module is completely compiled. Even without the `BEGIN` block, any "file scope" statements will get executed before anything after the `use` is compiled (then run). As for the desirability of file scope code in a module, by design, Perl expects a "used" module to run init/sanity-check code at "use time". This is why most modules end with `1;`. Perl is expecting the module to "return" a true value if everything is "A-Okay". Otherwise, a false value tells Perl something went wrong. Fetching the current working directory is a reasonable init action. Of course, if you are more comfortable using a `BEGIN` block, that's fine, too. TIMTOWTDI.	[reply] [d/l] [select]
Re^5: How to determine absolute path of current Perl file? by Discipulus (Canon) on Feb 29, 2016 at 22:51 UTC
thanks for your clarification RonW So using a `BEGIN` block inside a module to be used it's like to say: as soon as possible or even sooner. `#TestBegin.pm use strict; use warnings; BEGIN{print "inside BEGIN in the module ",__FILE__,"\n"} print "in the module ",__FILE__,"\n"; 1; perl -e "print qq(in the program $0\n);BEGIN{print qq(BEGIN in the pr +ogram $0\n)}" -MTestBegin inside BEGIN in the module TestBegin.pm in the module TestBegin.pm BEGIN in the program -e in the program -e` [download] And the only possibility to fail is: `perl -e "print qq(in the program $0\n);BEGIN{print qq(BEGIN in the pr +ogram\n)}use TestBegin;" BEGIN in the program inside BEGIN in the module TestBegin.pm in the module TestBegin.pm in the program -e` [download] L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l] [select]