add a buffer class

1 files changed, 46 insertions, 0 deletions

diff --git a/lib/Language/TECO/Buffer.pm b/lib/Language/TECO/Buffer.pm
new file mode 100644
index 0000000..53a80ba
--- /dev/null
+++ b/lib/Language/TECO/Buffer.pm
@@ -0,0 +1,46 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+package Language::TECO::Buffer;
+
+sub new {
+    return bless { buffer => '', pointer => 0 }, shift;
+}
+
+sub set {
+    my $self = shift;
+    my $pointer = shift;
+    return if $pointer < 0 || $pointer > length $self->{buffer}
+    $self->{pointer} = $pointer;
+}
+
+sub offset {
+    my $self = shift;
+    $self->set($self->{pointer} + shift);
+}
+
+sub insert {
+    my $self = shift;
+    my $text = shift;
+    substr($self->{buffer}, $self->{pointer}, 0) = $text;
+    $self->offset(length $text);
+}
+
+sub delete {
+    my $self = shift;
+    my $length = shift;
+    if ($length < 0) {
+        $length = -$length;
+        $self->{pointer} -= $length;
+    }
+    substr($self->{buffer}, $self->{pointer}, $length) = '';
+}
+
+sub endpos { length shift->{buffer} }
+
+sub curpos { shift->{pointer} }
+
+sub print {
+}
+
+1;