From 15cf3dcafba78dda35d8ae22066cbc75141737d8 Mon Sep 17 00:00:00 2001
From: "Peter J. Holzer" <hjp@hjp.at>
Date: Sun, 5 May 2013 19:35:11 +0200
Subject: [PATCH 1/2] added operator %

---
 rpn | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rpn b/rpn
index 70606be..268cc8f 100755
--- a/rpn
+++ b/rpn
@@ -10,7 +10,7 @@ my $stack_color = 'blue';
 print color $input_color;
 while (<>) {
     for (split) {
-	if (m{^[-+*/]|\*\*$}) {
+	if (m{^[-+*/%]|\*\*$}) {
 	    my $y = pop @stack;
 	    my $x = pop @stack;
 	    my $z = eval "$x $_ $y";

From 4e77d495e73e05af92f5459d83f4fc3ae8adc263 Mon Sep 17 00:00:00 2001
From: "Peter J. Holzer" <hjp@hjp.at>
Date: Sun, 29 Sep 2013 14:18:04 +0200
Subject: [PATCH 2/2] Implemented format and fixed parse error.

---
 rpn | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/rpn b/rpn
index 268cc8f..d366bfd 100755
--- a/rpn
+++ b/rpn
@@ -3,14 +3,16 @@ use warnings;
 use strict;
 use Term::ANSIColor;
 use Math::Trig ':pi';
+use Scalar::Util qw(looks_like_number);
 
 my @stack;
 my $input_color = 'red';
 my $stack_color = 'blue';
+my $format;
 print color $input_color;
 while (<>) {
     for (split) {
-	if (m{^[-+*/%]|\*\*$}) {
+	if (m{^([-+*/%]|\*\*)$}) {
 	    my $y = pop @stack;
 	    my $x = pop @stack;
 	    my $z = eval "$x $_ $y";
@@ -41,13 +43,20 @@ while (<>) {
 	} elsif (m{^ld$}) {
 	    my $x = pop @stack;
 	    push @stack, log($x) / log(2);
+	} elsif (m{^format$}) {
+	    $format = pop @stack;
 	} else {
 	    push @stack, $_;
 	}
     }
     for (@stack) {
 	print color $stack_color;
-	print "$_\n";
+	if ($format && looks_like_number($_)) {
+	    printf($format, $_);
+	    print "\n";
+	} else {
+	    print "$_\n";
+	}
     }
     print color $input_color;
 }