`which` for Perl, R, and Python libraries

p5which

#!/usr/bin/env perl
##
##  Print where a Perl 5 library was included from
##
##  Author:   Symkat
##  Source:   http://www.symkat.com/find-a-perl-modules-path
##  License:  Distributed under the same terms as Perl itself
##            <https://perldoc.perl.org/perlartistic>
##
use warnings;
use strict;
use File::Basename;

my $ME = basename($0);
my $ISSUESURL = 'https://gist.github.com/ernstki/61d554acf7e496130c8300620fb36910';

my $USAGE = <<USAGE;

$ME - show where a Perl 5 library was loaded from

usage:
    $ME <modulename> [<modulename> ...]

    Problems? File an issue at $ISSUESURL.

see also:
    http://www.symkat.com/find-a-perl-modules-path

USAGE

die "$USAGE" unless @ARGV;

# 0th place in @ARGV in Perl is first argument, not program name
if ($ARGV[0] =~ /--?h(elp)?/) {
    print "$USAGE";
    exit;
}

foreach my $module (@ARGV) {
    my $package = $module;

    # From This::That to This/That.pm
    s/::/\//g, s/$/.pm/ for $module;

    if (require $module) {
        print $package . " => " . $INC{$module} . "\n";
    }
}

pywhich

#!/usr/bin/env python
"""
Tell me where a Python package came from.

Author:   Adam Anderson
Source:   https://stackoverflow.com/a/42365058
License:  CC-BY-SA-4.0
"""
from __future__ import print_function

ISSUESURL = 'https://gist.github.com/ernstki/61d554acf7e496130c8300620fb36910'


def pywhich(module_name):
    module = __import__(module_name, globals(), locals(), [], 0)
    return module.__file__


if __name__ == "__main__":
    import sys
    import argparse

    parser = argparse.ArgumentParser(
            description="print where a Python package comes from",
            epilog="Problems? Report bugs at: {}".format(ISSUESURL))

    parser.add_argument('pkgs', metavar='PKG', nargs='+',
            help='package(s) to look for')

    opts = parser.parse_args()

    for pkg in opts.pkgs:
        try:
            print(pkg, "=>", pywhich(pkg))
        except ImportError:
            parser.error("No such module '{}'.".format(pkg))

rwhich

#!/usr/bin/env Rscript
##
##  Print the library path(s) of any package names given as arguments
##
##  Author:   Kevin Ernst
##  Date:     22 April 2021
##  Source:   https://gist.github.com/ernstki/61d554acf7e496130c8300620fb36910
##  License:  Unlicense <https://unlicense.org>
##

# startsWith is not present in base until 3.6.x
if (R.Version()$major < 4 && R.Version()$minor < 6) {
    startsWith <- function(x, prefix) {
        substring(x, 1, nchar(prefix)) == prefix  
    }
}

helpmsg <- "usage: rwhich [-h|--help] PKG [PKG...]"
argv <- commandArgs(trailingOnly=TRUE)

if (!length(argv)) {
    stop(helpmsg)
}

if (startsWith(argv[1], "-h") || startsWith(argv[1], "--h")) {
    cat("rwhich - show where R libraries come from\n", helpmsg, sep="\n")
    quit()
}

tryPackage <- function(p) {
    tryCatch(
        find.package(p),
        # if you forget to make this a function, you'll get the error "attempt
        # to apply to non-function" (without much helpful context)
        # h/t: https://www.programmingr.com/r-error-messages/error-attempt-to-apply-non-function
        error = function(e) { paste("No such package", p) }
    )
}

ret <- 0

for (pkg in argv) {
    pkgpath <- tryPackage(pkg)
    if (startsWith(pkgpath, "No such package")) {
        ret <- ret + 1
    }
    cat(cat(pkg, "=>", pkgpath), sep="\n")
}

quit(status=ret)
# vim: ft=r