From b9ed52e3684e49b9b00ef08b29111758cc4777ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Wed, 26 May 2021 01:36:03 +0200
Subject: Add main 'mum' script

---
 src/mum | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100755 src/mum

diff --git a/src/mum b/src/mum
new file mode 100755
index 0000000..3c7d0b0
--- /dev/null
+++ b/src/mum
@@ -0,0 +1,121 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use feature qw/switch/;
+no warnings qw/experimental::smartmatch/;
+
+use Data::Dumper;
+
+# Open TTY for reading and writing
+
+open my $tty, '+<:unix', '/dev/tty' or die "Could not open /dev/tty: $!";
+
+# Define range syntax
+
+my @range; # range (one/two references)
+our %ref; # current reference in range
+my $d = qr{
+ (?(DEFINE)
+  (?<range>                     (?{ @range = () })
+            ( (?&ref)
+	    | (?&ref),(?&ref)
+	    | (?&pattern)
+	    )
+                                (?{ push @range, \%ref })
+  )
+  (?<ref> ( (\d+)               (?{ local %ref = (line => $^N) })
+          | (\.|\$)             (?{ local %ref = (spec => $^N) })
+          | ' ([a-z])           (?{ local %ref = (mark => $^N) })
+          | /((\\/|[^/])*)/     (?{ local %ref = (next => $^N) })
+          | \?((\\\?|[^?])*)\?  (?{ local %ref = (prev => $^N) })
+          )
+          ( ([+-] \d+)          (?{ local %ref = (%ref, plus => $^N) })
+          )?
+  )
+  (?<pattern> g/((\\/|[^/])*)/  (?{ local %ref = (patt => $^N) })
+  )
+ )
+}x;
+
+# Define program state
+
+my $message = 1; # selected message
+
+# Run program
+
+while () {
+	print $tty "$message& ";
+
+	# Read next command from user
+
+	my $cmd = <$tty>;
+	$cmd = '' if not $cmd;
+	chomp $cmd;
+	$cmd =~ s/^\s+|\s+$//g;
+
+	# Parse user-given command
+
+	for ($cmd) {
+		# q
+		if (/^q$/) {
+			exit;
+		}
+
+		# range without command
+		elsif (/^(?&range) \Z $d/x) {
+			print Dumper(@range), "\n";
+			# select last message in range
+			print "range without command\n";
+		}
+
+		# +/- (++/--)
+		elsif (/^(?<num> \d*) (?<dir> (\+\+?|--?)) \Z/x) {
+			for ($+{dir}) {
+				$message += $+{num} || 1 if /\+/;
+				$message -= $+{num} || 1 if /-/;
+				goto h if length($_) > 1;
+			}
+		}
+
+		# c
+		elsif (/^c\s+(.*)/) {
+			chdir $1;
+		}
+
+		# h
+		elsif (/^ (?&range)? h \Z $d/x) {
+h:
+			print "h\n";
+		}
+
+		# p
+		elsif (/^ (?&range)? p \Z $d/x) {
+			print Dumper(@range), "\n";
+			print "p\n";
+		}
+
+		# |
+		elsif (/^ (?&range)? \| (?<rest>.+) $d/x) {
+			print "|\n";
+		}
+
+		# !
+		elsif (/^!/) {
+			$cmd =~ s/!//;
+			system $cmd;
+			print "!\n";
+		}
+
+		# empty command
+		elsif (/^$/) {
+			$message++;
+		}
+
+		# unrecognized command
+		else {
+			warn "unrecognized command syntax\n";
+			next;
+		}
+	}
+}
-- 
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