X-Git-Url: http://git.shiar.net/descalc.git/blobdiff_plain/4e1d9535fda6685e53ce570ca4e4cd6c260f55d3..090ac304afe801cb3e72ced0941ff2a874a98cc9:/28_stack.pm?ds=sidebyside

diff --git a/28_stack.pm b/28_stack.pm
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+# improved stack functionality for DCT, by Shiar
+
+# 1.13.0 200411042045 - added swap and stack from main
+#                     - renamed to "stack"
+#                     - stack cycle would crash with undefined stack
+# 1.10.1 200410150045 - set initial value to prevent crash when no undos set
+# 1.10.0 200410150000 - single-level undo from main
+
+use strict;
+use warnings;
+
+my $undo = [];  # stack backup
+my $stackpos = 0;  # position of stack browser
+
+push @{$hook{preaction}}, sub {
+	if ($_[0] >= 0) {
+		$undo = [@stack];  # backup stack
+		$stackpos = 0;  # reset position of stack navigation
+	} # stack-modifying operations (type>=0)
+}; # preaction
+
+$action{undo}  = [-1, sub { ($undo, @stack) = ([@stack], @$undo) }]; # undo/redo
+
+$action{swap}  = [ 2, sub { reverse @_ }]; # swap x<->y
+
+$action{stack} = [-2, sub {
+	$stackpos %= @stack if @stack;  # cycle
+	$val{i} = $stack[$stackpos++];
+}]; # stack
+
+return {
+	author  => "Shiar",
+	title   => "stack functions",
+	version => "1.13",
+};
+