Add minimal interpreter implementation in Ruby

Also, convert the interpreter test cases to Ruby

Author: peret

ports-r/scheme.rb

@@ -0,0 +1,30 @@
+require_relative "parser"
+
+module Scheme
+  GLOBAL_ENV = {
+    :+ => proc { |a, b| a + b },
+    :* => proc { |a, b| a * b }
+  }
+
+  def evaluate(tokens)
+    if tokens.is_a?(String)
+      tokens
+    elsif tokens.is_a?(Numeric)
+      tokens
+    elsif tokens.is_a?(Array)
+      token = tokens.shift
+      procedure = evaluate(token)
+      procedure.call(
+        *(tokens.map { |t| evaluate(t) })
+      )
+    elsif tokens.is_a?(Symbol)
+      GLOBAL_ENV[tokens]
+    end
+  end
+
+  def evaluate_string(source)
+    Scheme.evaluate(Parser.parse_string(source))
+  end
+
+  module_function :evaluate_string, :evaluate
+end

ports-r/semantic-tests.rb

@@ -0,0 +1,65 @@
+require "json"
+require "pathname"
+
+# Helper function to check if result matches expected output
+def matches(result, target)
+  if target.is_a?(Hash) && target.key?("type")
+    return result.is_a?(StandardError)
+  end
+
+  if target.is_a?(Array)
+    return false unless result.is_a?(Array)
+    return false unless result.length == target.length
+
+    match = true
+    target.each_with_index do |t, i|
+      match &&= matches(result[i], t)
+    end
+    return match
+  end
+
+  if result.is_a?(Symbol)
+    return result.to_s == target
+  end
+
+  result == target
+end
+
+# Get current directory
+dirname = File.dirname(__FILE__)
+
+# Load test cases
+test_table = []
+begin
+  tests_path1 = File.join(dirname, "../ports/lispy-tests.json")
+  tests_path2 = File.join(dirname, "../ports/lispy-tests2.json")
+
+  tests1 = JSON.parse(File.read(tests_path1))
+  test_table.concat(tests1)
+
+  tests2 = JSON.parse(File.read(tests_path2))
+  test_table.concat(tests2)
+rescue => error
+  puts "Error loading test files: #{error.message}"
+  exit(1)
+end
+
+# Import the scheme module - assuming it's defined in a Ruby file
+require_relative "scheme"
+
+# Run tests
+test_table.each do |entry|
+  input = entry["input"]
+
+  begin
+    eval_result = Scheme.evaluate_string(input)
+  rescue => error
+    eval_result = error
+  end
+
+  if matches(eval_result, entry["expected"])
+    puts "✅: #{input}"
+  else
+    puts "❌: #{input} got #{eval_result}[#{eval_result.class}] instead of #{entry["expected"]}[#{entry["expected"].class}]"
+  end
+end