In Beyond "Hello World" - comparing starter code in C, Rust, Python, TypeScript and more, Tai Kedzierski proposed the "Hello Y'All" program as a beefed-up version of the classic "Hello World":
- The example takes at least one command line argument, and handles the event of no-arguments
- The example requires a function to be placed in a second file in a subfolder
- The function returns a value
- The example loops over CLI arguments, calling one at a time to the function, and each time prints the returned value, concatenated to other text
- Include the overall bare-minimum instructions include how to build the program (if necessary) and run it
Unfortunately, some languages make splitting code into several files annoyingly difficult (this is the point of including that in the spec!). When he got to Perl he gave up and pleaded:
This is just a sample of the hair-pulling infuriation trying to hunt down how to import a damn file from a subfolder. It seems this is forbidden voodoo. Perlists, please prove me wrong, I beg of you...
This repo copies his Perl code, gets the import working, and finishes the rest
of his spec by handling command-line arguments. I am a very rusty Perl hacker
and I don't think this is very idiomatic: in particular, Perl deliberately
excludes the script's directory from @INC for security reasons, so adding it
back is unlikely to be a good idea. It's Perl, though, so it's not gonna stop
you. The main thing Tai was missing was the need to use Exporter in the
module file; without that, symbols aren't exported into the importing namespace
when you call use.
Why do things like that? Well, Perl's use function requires a module
(loading it in from the filesystem) and then calls its import method, which
is just an ordinary static method call. That means you can do anything in
that method, and have it happen at compile time. See
SVG::GD or
Lingua::Romana::Perligata
for the kind of thing this makes possible. The standard Exporter module
provides (in ordinary Perl code) an import method that implements the usual
export semantics; people have written several alternative exporters and put
them on CPAN.