From 20601f5f15fea89de58a4cd87870b88351d6a59f Mon Sep 17 00:00:00 2001
From: Ben Harris <bjh21@bjh21.me.uk>
Date: Tue, 23 Jul 2019 21:25:20 +0100
Subject: [PATCH] perl: Factor out common features of Vectors and Lists into a
 superclass.

The two classes are identical apart from their names.
---
 perl/types.pm | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/perl/types.pm b/perl/types.pm
index 4eba2b3e..450fee2a 100644
--- a/perl/types.pm
+++ b/perl/types.pm
@@ -126,10 +126,10 @@ sub _keyword_Q { ((ref $_[0]) =~ /^String/) && ${$_[0]} =~ /^\x{029e}/; }
 }
 
 
-# Lists
+# Sequences
 
 {
-    package List;
+    package Sequence;
     sub new  { my $class = shift; bless {'meta'=>$nil, 'val'=>$_[0]}, $class }
     sub nth { $_[0]->{val}->[$_[1]]; }
     #sub _val { $_[0]->{val}->[$_[1]]->{val}; } # return value of nth item
@@ -137,6 +137,13 @@ sub _keyword_Q { ((ref $_[0]) =~ /^String/) && ${$_[0]} =~ /^\x{029e}/; }
     sub slice { my @arr = @{$_[0]->{val}}; List->new([@arr[$_[1]..$_[2]]]); }
 }
 
+# Lists
+
+{
+    package List;
+    use parent -norequire, 'Sequence';
+}
+
 sub _list_Q { (ref $_[0]) =~ /^List/ }
 
 
@@ -144,11 +151,7 @@ sub _list_Q { (ref $_[0]) =~ /^List/ }
 
 {
     package Vector;
-    sub new  { my $class = shift; bless {'meta'=>$nil, 'val'=>$_[0]}, $class }
-    sub nth { $_[0]->{val}->[$_[1]]; }
-    #sub _val { $_[0]->{val}->[$_[1]]->{val}; } # return value of nth item
-    sub rest { my @arr = @{$_[0]->{val}}; List->new([@arr[1..$#arr]]); }
-    sub slice { my @arr = @{$_[0]->{val}}; List->new([@arr[$_[1]..$_[2]]]); }
+    use parent -norequire, 'Sequence';
 }
 
 sub _vector_Q { (ref $_[0]) =~ /^Vector/ }
-- 
2.20.1