From 2c4d11d53fc2ce6d99d520cb42b13ec06b5baf16 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Wed, 26 May 2021 14:32:00 +0200
Subject: mum: Implement mbox index reading, range parsing

For clarity's sake, I've also converted program-global variables
to uppercase.
---
 src/mum | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 116 insertions(+), 24 deletions(-)

diff --git a/src/mum b/src/mum
index cba5c11..07cec1d 100755
--- a/src/mum
+++ b/src/mum
@@ -6,33 +6,30 @@ use warnings;
 
 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
+my @RANGE; # range (one/two references)
+our %REF; # current reference
+
 my $d = qr{
  (?(DEFINE)
-  (?<range>                                                   (?{ @range = () })
+  (?<range>                                                   (?{ @RANGE = () })
             ( (?&ref)
 	    | (?&ref),(?&ref)
 	    | (?&grep)
 	    )
-                                                       (?{ push @range, \%ref })
+                                                       (?{ push @RANGE, \%REF })
   )
-  (?<ref> ( (\d+)                              (?{ local %ref = (line => $^N) })
-          | (\.|\$)                            (?{ local %ref = (spec => $^N) })
-          | ' ([a-z])                          (?{ local %ref = (mark => $^N) })
-          | (?&next)                           (?{ local %ref = (next => $^R) })
-          | (?&prev)                           (?{ local %ref = (prev => $^R) })
+  (?<ref> ( (\d+)                              (?{ local %REF = (line => $^N) })
+          | (\.|\$)                            (?{ local %REF = (spec => $^N) })
+          | ' ([a-z])                          (?{ local %REF = (mark => $^N) })
+          | (?&next)                           (?{ local %REF = (next => $^R) })
+          | (?&prev)                           (?{ local %REF = (prev => $^R) })
           )
-          ( ([+-] \d+)                 (?{ local %ref = (%ref, plus => 0+$^N) })
+          ( ([+-] \d+)                 (?{ local %REF = (%REF, plus => 0+$^N) })
           )?
   )
-  (?<grep> g((?&next))                         (?{ local %ref = (grep => $^R) })
+  (?<grep> g((?&next))                         (?{ local %REF = (grep => $^R) })
   )
   (?<next> /(([^/\\]++ | \\.)*+)/                                     (?{ $^N })
   )
@@ -43,12 +40,22 @@ my $d = qr{
 
 # Define program state
 
-my $message = 1; # selected message
+my $MESSAGE = 0; # selected message
+my $INDEX = '-'; # loaded mbox index
+my @MESSAGES; # loaded messages
+my %MARKS; # saved marks
+
+# Open TTY for reading and writing
+
+open my $tty, '+<:unix', '/dev/tty' or die "Could not open /dev/tty: $!";
 
-# Run program
+# Run main loop
 
 while () {
-	print $tty "$message& ";
+	$MESSAGE = 1 if $MESSAGE < 1;
+	$MESSAGE = @MESSAGES if $MESSAGE > @MESSAGES;
+
+	print $tty "$MESSAGE:$INDEX& ";
 
 	# Read next command from user
 
@@ -67,16 +74,19 @@ while () {
 
 		# range without command
 		elsif (/^(?&range) \Z $d/x) {
-			print Dumper(@range), "\n";
 			# select last message in range
-			print "range without command\n";
+			my ($a, $b);
+			$a = toloc(0, $RANGE[0]) if @RANGE > 1;
+			$b = toloc($a, $RANGE[$#RANGE]) or next;
+			$MESSAGE = $b;
 		}
 
 		# +/- (++/--)
 		elsif (/^(?<num> \d*) (?<dir> (\+\+?|--?)) \Z/x) {
+			my $num = $+{num} || 1;
 			for ($+{dir}) {
-				$message += $+{num} || 1 if /\+/;
-				$message -= $+{num} || 1 if /-/;
+				$MESSAGE += $num if /\+/;
+				$MESSAGE -= $num if /-/;
 				goto h if length($_) > 1;
 			}
 		}
@@ -94,7 +104,7 @@ h:
 
 		# p
 		elsif (/^ (?&range)? p \Z $d/x) {
-			print Dumper(@range), "\n";
+			print Dumper(@RANGE), "\n";
 			print "p\n";
 		}
 
@@ -110,9 +120,31 @@ h:
 			print "!\n";
 		}
 
+		# r[a]
+		elsif (/^ra? \s+ (?<index> .*)/x) {
+			my $idx = $+{index};
+			$idx =~ s/\.i$//;
+			$idx .= '.i'; # be sure to open index and not mbox
+			open my $h, '<', $idx or do {
+				warn "failed to open $idx: $!\n";
+				next;
+			};
+			($INDEX = $idx) =~ s/\.i$//;
+			local $/ = '';
+			@MESSAGES = () if not $cmd =~ /^ra/; # overwrite
+			my $offset = 0;
+			while (<$h>) {
+				s/^From .*\n/$&M-Index-Offset: $offset\n/;
+				push @MESSAGES, $_;
+				$offset += length $_;
+			}
+			close $h;
+			print scalar @MESSAGES, " messages\n";
+		}
+
 		# empty command
 		elsif (/^$/) {
-			$message++;
+			$MESSAGE++;
 		}
 
 		# unrecognized command
@@ -122,3 +154,63 @@ h:
 		}
 	}
 }
+
+# Subroutines
+
+# Parse ref/grep and return corresponding location
+sub toloc {
+	my $start = shift;     # starting position for searches (optional)
+	my %ref = %{(shift)};  # reference to parse
+	my $loc;               # location to return
+
+	if ($ref{line}) {
+		$loc = $ref{line};
+	}
+
+	elsif ($ref{mark}) {
+		if ($MARKS{$ref{mark}}) {
+			$loc = $MARKS{$ref{mark}};
+		} else {
+			warn "mark '$ref{mark} not set\n";
+			return;
+		}
+	}
+
+	elsif ($ref{spec}) {
+		$loc = $MESSAGE if $ref{spec} eq '.';
+		$loc = scalar @MESSAGES if $ref{spec} eq '$';
+	}
+
+	elsif ($ref{next}) {
+		$start = 1 if not $start;
+		$loc = $start-1;
+		for (@MESSAGES[$start-1..$#MESSAGES]) {
+			$loc++;
+			goto found if /$ref{next}/;
+		}
+		warn "pattern /$ref{next}/ not found\n";
+		return;
+	}
+
+	elsif ($ref{prev}) {
+		$start = @MESSAGES if not $start;
+		$loc = $start-1;
+		for (@MESSAGES[0..$start-1]) {
+			$loc--;
+			goto found if m?$ref{prev}?;
+		}
+		warn "pattern ?$ref{prev}? not found\n";
+		return;
+	}
+
+	elsif ($ref{grep}) {
+		# to be implemented
+		return;
+	}
+
+found:
+	$loc += $ref{plus} if $ref{plus};
+	$loc = 1 if $loc < 1;
+	$loc = @MESSAGES if $loc > @MESSAGES;
+	return $loc;
+}
-- 
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