chervil/spec/ast/definition_spec.rb

module Chervil
  RSpec.describe AST::Definition do
    it 'evaluates' do
      env = Env.new
      AST::Definition.new(
        AST::Identifier.new("x"),
        AST::Number.new(5.0)
      ).evaluate(env)
      expect(env.get("x")).to eq(AST::Number.new(5.0))
    end

    it 'throws an error if bound to an unbound variable' do
      env = Env.new
      result = AST::Definition.new(
        AST::Identifier.new("x"),
        AST::Identifier.new("y"),
      ).evaluate(env)
      expect(result).to eq(
        ::Chervil::Error.new("unbound variable y")
      )
    end
  end
end