argument support (-d for debug)

To facilitate debugging, I've reified the handler descriptions, which
were comments previously.  Now, they've been made strings passed to
the `handle` subroutine, which sets `$handler`, which then (in case of
-d) can be read by `fail`, which notifies the user that a handler has
failed.

1 files changed, 76 insertions, 30 deletions

diff --git a/dwim.pl b/dwim.pl
index 6d2c445..de14ae5 100755
--- a/dwim.pl
+++ b/dwim.pl
@@ -6,66 +6,112 @@ use v5.24;
 use warnings;
 use strict;
 use Path::ExpandTilde;
+use subs qw/path env handle fail arguments/;
 
-die "usage: $0 phrase\n" if scalar @ARGV > 1;
-my $p;
-$p = $ARGV[0] if defined $ARGV[0];
-$p = `xsel -o` if not defined $ARGV[0];
+my ($phrase, %o) = arguments "usage: $0 parse\n", 1, d => 0;
+$phrase = `xsel -o` if not defined $phrase;
 
-my $OPENER = env (OPENER => "u");
-my $EDITOR = env (EDITOR => "vi");
-my $MAILER = env (MAILER => "mutt");
-my $MAILROOT = env (MAILROOT => "/home/john/mail/");
+my @LAUNCHER = split /\s/, env(OPENER => "urxvtc -e");
+my @EDITOR = split /\s/, env(EDITOR => "vi");
+my @MAILER = split /\s/, env(MAILER => "mutt");
+my @MAILDIR_VIEWER = split /\s/, env(MAILDIR_VIEWER => "mutt -f");
+my $MAILROOT = env(MAILROOT => "/home/john/mail/");
 
-for ($p) {
-	# web address
+our $handler;
+
+for ($phrase) {
 	if (/^(https?:\/\/.+)$/) {
+		handle "web address";
 		exec "firefox", "$1"
 	}
 
-	# e-mail address
 	if (/^(mailto:\/\/.+)$/ or /^(.+@.+\.\w+)$/) {
-		exec $MAILER, "$1"
+		handle "e-mail address";
+		exec @MAILER, "$1"
 	}
 
-	# file:line
 	if (/^(.+):(\d+)(:.*?)?$/) {
-		my $f = path($1);
-		exec $OPENER, $EDITOR, "-c", ":$2", "$f"
+		handle "file:line";
+		my $p = path($1);
+		exec @LAUNCHER, @EDITOR, "-c", ":$2", "$p"
 	}
 
-	# file:query (if file exists)
 	if (/^(.+):(.+)$/) {
-		my $f = path($1);
-		exec $OPENER, $EDITOR, "-c", "/$2", "$f" if -e $f;
+		handle "file:query (like grep)";
+		my $p = path($1);
+		exec @LAUNCHER, @EDITOR, "-c", "/$2", "$p" if -e $p;
+		fail "file not found" if $o{d};
 		# otherwise fall through
 	}
 
-	# maildir (if it matches) or file (if it exists)
 	if (/^([^\s]+)$/) {
-		my $f = path($1);
-		exec $OPENER, $MAILER, "-f", "$f" if $f =~ /^$MAILROOT/; # maildir
-		exec $OPENER, $EDITOR, "$f" if -e $f; #file
+		handle "maildir / directory / file";
+		my $p = path($1);
+		exec @LAUNCHER, @MAILDIR_VIEWER, "$p" if $p =~ /^$MAILROOT/; # maildir
+		exec @LAUNCHER, @EDITOR, "$p" if -e $p; #file
+		fail "file not found" if $o{d};
 		# otherwise fall through
 	}
 
 	# otherwise
-	die "no handler matched by: $p\n"
+	die "no handler matched by: $phrase\n"
 }
 
 sub path {
-	my $f = shift;
-	$f = expand_tilde($f);
-	return $f if $f =~ /^\// or $f =~ /^~/;
-	my $t = `xtitle`;
-	chomp $t;
-	die "couldn't retrieve directory\n" if ! -d $t and ! -d ($t = dirname $t);
-	return "$t/$f";
+	my $n = shift;
+	$n = expand_tilde($n);
+	return $n if $n =~ /^\// or $n =~ /^~/;
+	my $d = `xtitle`;
+	chomp $d;
+	die "couldn't retrieve current directory\n" if ! -d $d and ! -d ($d = dirname $d);
+	return "$d/$n";
 }
 
+# take K => V and return environment variable K if defined, otherwise V
 sub env {
 	my %h = @_;
 	my $k = (keys %h)[0];
 	return $ENV{$k} if defined ${ENV}{$k};
 	return $h{$k};
 }
+
+sub handle {
+	$handler = shift;
+	print STDERR "$handler MATCHED\n" if $o{d};
+}
+
+sub fail {
+	my $msg = shift;
+	print STDERR "$handler FAILED: $msg\n";
+}
+
+# parse ARGV and return list of positionals and hash of option values
+sub arguments {
+	my $usage = shift;  # usage string
+	my $n = shift;      # number of positional arguments
+	my %options = @_;   # option specification
+
+	# parse options (end upon --)
+
+	while ($_ = shift @ARGV) {
+		last if /^--$/;
+		unshift @ARGV, $_ and last if not /^-/;
+
+		s/^-//;
+		if (defined $options{$_}) { $options{$_} = 1 }
+		else { die $usage; }
+	}
+
+	# fill @positionals with $n strings (with undef upon empty ARGV)
+
+	my @positionals;
+	my $i = 0;
+	while (++$i <= $n) {
+		if ($_ = shift @ARGV) { push @positionals, $_ }
+		else { push @positionals, undef }
+	}
+
+	die $usage if @ARGV; # all processing should be done
+
+	return @positionals, %options;
+}