structural_parser_spec.rb

require_relative 'spec_helper'

describe Parsers::StructuralParser do
  before do
    @parser = Parsers::AnnotationParser.new
  end
  
  describe 'a simple, full structural constraint' do
    it 'is parsed into a single constraint' do
      '#write(String, Fixnum=) -> NilClass'.should parse_to(
          Types::StructuralType.new('write',
            [Types::ClassType.new('String', :covariant),
             Types::ClassType.new('Fixnum', :invariant)],
            Types::ClassType.new('NilClass', :covariant)))
    end
    
    it 'parses with an empty arg list' do
      '#write() -> NilClass'.should parse_to(
          Types::StructuralType.new('write',
            [], Types::ClassType.new('NilClass', :covariant)))
    end
  end
  
  describe 'a full structural constraint in Go-style' do
    it 'is parsed into the equivalent constraint' do
      '#write(String) NilClass'.should parse_to(
          Types::StructuralType.new('write',
            [Types::ClassType.new('String', :covariant)],
            Types::ClassType.new('NilClass', :covariant)))
    end
    
    it 'parses with an empty arg list' do
      '#write() NilClass'.should parse_to(
          Types::StructuralType.new('write',
            [], Types::ClassType.new('NilClass', :covariant)))
    end
  end
  
  describe 'a structural constraint without a return type' do
    it 'is parsed into a constraint with an empty return type constraint set' do
      '#write(String, Fixnum=)'.should parse_to(
          Types::StructuralType.new('write',
            [Types::ClassType.new('String', :covariant),
             Types::ClassType.new('Fixnum', :invariant)],
            []))
    end
    
    it 'parses with an empty arg list' do
      '#write()'.should parse_to(
          Types::StructuralType.new('write', [], []))
    end
  end

  describe 'a structural constraint with an elided argument list' do
    it 'is parsed into a constraint with an empty return type and argument constraint set' do
      '#write->Fixnum-'.should parse_to(
          Types::StructuralType.new('write', [],
            Types::ClassType.new('Fixnum', :contravariant)))
    end
  end
  
  describe 'a structural constraint with no arguments or return types specified' do
    it 'is parsed into a constraint with an empty return type and argument constraint set' do
      '#write'.should parse_to(Types::StructuralType.new('write', [], []))
    end
  end
end