chervil/spec/ast/conditional_spec.rb

module Chervil
  RSpec.describe AST::Conditional do
    it 'returns the true branch given #t' do
      expect(AST::Conditional.new(
        AST::Boolean.new(true),
        AST::Number.new(1.0),
        AST::Number.new(0.0),
      ).evaluate(Env.new)).to eq(
        1.0
      )
    end

    it 'returns the false branch given #f' do
      expect(AST::Conditional.new(
        AST::Boolean.new(false),
        AST::Number.new(1.0),
        AST::Number.new(0.0),
      ).evaluate(Env.new)).to eq(
        0.0
      )
    end

    it 'evaluates complex predicates' do
      expect(AST::Conditional.new(
        AST::Application.new(
          AST::Identifier.new(">"),
          [
            AST::Number.new(2.0),
            AST::Number.new(1.0),
          ]
        ),
        AST::Number.new(2.0),
        AST::Number.new(1.0),
      ).evaluate(Env.new)).to eq(
        2.0
      )
    end

    it 'evaluates complex branches' do
      expect(AST::Conditional.new(
        AST::Boolean.new(true),
        AST::Application.new(
          AST::Identifier.new("+"),
          [
            AST::Number.new(2.0),
            AST::Number.new(1.0),
          ]
        ),
        AST::Number.new(0.0)
      ).evaluate(Env.new)).to eq(
        3.0
      )
    end
  end
end