From adfe08560d981d7326a208a86308d783db3119bc Mon Sep 17 00:00:00 2001
From: Gregg Kellogg <gregg@greggkellogg.net>
Date: Thu, 16 Dec 2021 16:20:23 -0800
Subject: [PATCH] Support Common Lisp vectors (`#(foo)`) using the Ruby Vector
 class.

For #16.
---
 lib/sxp/extensions.rb         | 21 +++++++++++++++------
 lib/sxp/reader/common_lisp.rb |  5 ++++-
 spec/common_lisp_spec.rb      | 10 +++++++---
 spec/extensions_spec.rb       | 12 ++++++++++++
 4 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/lib/sxp/extensions.rb b/lib/sxp/extensions.rb
index 3c96aea..d88e330 100644
--- a/lib/sxp/extensions.rb
+++ b/lib/sxp/extensions.rb
@@ -1,5 +1,6 @@
 # -*- encoding: utf-8 -*-
 require 'bigdecimal'
+require 'matrix'
 require 'time'
 
 ##
@@ -146,12 +147,6 @@ class Array
   ##
   # Returns the SXP representation of this object.
   #
-  # If array is of the form `[:base, uri, ..]`, the base_uri is taken from the second value
-  #
-  # If array is of the form `[:prefix, [..], ..]`, prefixes are taken from the second value
-  #
-  # Prefixes always are terminated by a ':'
-  #
   # @param [Hash{Symbol => RDF::URI}] prefixes(nil)
   # @param [RDF::URI] base_uri(nil)
   # @return [String]
@@ -160,6 +155,20 @@ def to_sxp(prefixes: nil, base_uri: nil)
   end
 end
 
+##
+# Extensions for Ruby's `Vector` class.
+class Vector
+  ##
+  # Returns the SXP representation of this object.
+  #
+  # @param [Hash{Symbol => RDF::URI}] prefixes(nil)
+  # @param [RDF::URI] base_uri(nil)
+  # @return [String]
+  def to_sxp(prefixes: nil, base_uri: nil)
+    '#(' << to_a.map { |x| x.to_sxp(prefixes: prefixes, base_uri: base_uri) }.join(' ') << ')'
+  end
+end
+
 ##
 # Extensions for Ruby's `Hash` class.
 class Hash
diff --git a/lib/sxp/reader/common_lisp.rb b/lib/sxp/reader/common_lisp.rb
index 9b683fb..42e3619 100644
--- a/lib/sxp/reader/common_lisp.rb
+++ b/lib/sxp/reader/common_lisp.rb
@@ -1,4 +1,6 @@
 # -*- encoding: utf-8 -*-
+require 'matrix'
+
 module SXP; class Reader
   ##
   # A Common Lisp S-expressions parser.
@@ -88,7 +90,8 @@ def read_symbol(delimiter = nil)
     #
     # @return [Array]
     def read_vector
-      raise NotImplementedError, "#{self.class}#read_vector" # TODO
+      list = read_list(')')
+      Vector.[](*list)
     end
 
     ##
diff --git a/spec/common_lisp_spec.rb b/spec/common_lisp_spec.rb
index 3d317ea..b9526c1 100644
--- a/spec/common_lisp_spec.rb
+++ b/spec/common_lisp_spec.rb
@@ -86,13 +86,17 @@
     end
   end
 
-  context "when reading vectors", pending: "Support for vectors" do
+  context "when reading vectors" do
     it "reads `#()` as an empty vector" do
-      expect(read(%q(#()))).to eq []
+      expect(read(%q(#()))).to eq Vector[]
     end
 
     it "reads `#(1 2 3)` as a vector" do
-      expect(read(%q(#(1 2 3)))).to eq [1, 2, 3]
+      expect(read(%q(#(1 2 3)))).to eq Vector[1, 2, 3]
+    end
+
+    it "reads `#(hello \"world\")` as a vector" do
+      expect(read(%q(#(hello "world")))).to eq Vector[:hello, "world"]
     end
   end
 
diff --git a/spec/extensions_spec.rb b/spec/extensions_spec.rb
index 5e2512a..901b1c8 100644
--- a/spec/extensions_spec.rb
+++ b/spec/extensions_spec.rb
@@ -26,6 +26,18 @@
   end
 end
 
+describe "Vector" do
+  {
+    Vector[] => %q(#()),
+    Vector[1, 2, 3] => %q(#(1 2 3)),
+    Vector[:hello, "world"] => %q(#(hello "world"))
+  }.each do |value, result|
+    it "returns #{result.inspect} for #{value.inspect}" do
+      expect(value.to_sxp).to eq result
+    end
+  end
+end
+
 describe "RDF::Node#to_sxp" do
   specify { expect(RDF::Node.new("a").to_sxp).to eq %q(_:a)}
 end