require_relative '../spec_helper' require_relative 'fixtures/classes' describe "A lambda literal -> () { }" do SpecEvaluate.desc = "for definition" it "returns a Proc object when used in a BasicObject method" do klass = Class.new(BasicObject) do def create_lambda -> { } end end klass.new.create_lambda.should be_an_instance_of(Proc) end it "does not execute the block" do -> { fail }.should be_an_instance_of(Proc) end it "returns a lambda" do -> { }.lambda?.should be_true end ruby_version_is "2.6" do it "may include a rescue clause" do eval('-> do raise ArgumentError; rescue ArgumentError; 7; end').should be_an_instance_of(Proc) end it "may include a ensure clause" do eval('-> do 1; ensure; 2; end').should be_an_instance_of(Proc) end end it "has its own scope for local variables" do l = -> arg { var = arg # this would override var if it was declared outside the lambda l.call(arg-1) if arg > 0 var } l.call(1).should == 1 end context "assigns no local variables" do evaluate <<-ruby do @a = -> { } @b = ->() { } @c = -> () { } @d = -> do end ruby @a.().should be_nil @b.().should be_nil @c.().should be_nil @d.().should be_nil end end context "assigns variables from parameters" do evaluate <<-ruby do @a = -> (a) { a } ruby @a.(1).should == 1 end evaluate <<-ruby do @a = -> ((a)) { a } ruby @a.(1).should == 1 @a.([1, 2, 3]).should == 1 end evaluate <<-ruby do @a = -> ((*a, b)) { [a, b] } ruby @a.(1).should == [[], 1] @a.([1, 2, 3]).should == [[1, 2], 3] end evaluate <<-ruby do @a = -> (a={}) { a } ruby @a.().should == {} @a.(2).should == 2 end evaluate <<-ruby do @a = -> (*) { } ruby @a.().should be_nil @a.(1).should be_nil @a.(1, 2, 3).should be_nil end evaluate <<-ruby do @a = -> (*a) { a } ruby @a.().should == [] @a.(1).should == [1] @a.(1, 2, 3).should == [1, 2, 3] end evaluate <<-ruby do @a = -> (a:) { a } ruby -> { @a.() }.should raise_error(ArgumentError) @a.(a: 1).should == 1 end evaluate <<-ruby do @a = -> (a: 1) { a } ruby @a.().should == 1 @a.(a: 2).should == 2 end evaluate <<-ruby do @a = -> (**) { } ruby @a.().should be_nil @a.(a: 1, b: 2).should be_nil -> { @a.(1) }.should raise_error(ArgumentError) end evaluate <<-ruby do @a = -> (**k) { k } ruby @a.().should == {} @a.(a: 1, b: 2).should == {a: 1, b: 2} end evaluate <<-ruby do @a = -> (&b) { b } ruby @a.().should be_nil @a.() { }.should be_an_instance_of(Proc) end evaluate <<-ruby do @a = -> (a, b) { [a, b] } ruby @a.(1, 2).should == [1, 2] -> { @a.() }.should raise_error(ArgumentError) -> { @a.(1) }.should raise_error(ArgumentError) end evaluate <<-ruby do @a = -> ((a, b, *c, d), (*e, f, g), (*h)) do [a, b, c, d, e, f, g, h] end ruby @a.(1, 2, 3).should == [1, nil, [], nil, [], 2, nil, [3]] result = @a.([1, 2, 3], [4, 5, 6, 7, 8], [9, 10]) result.should == [1, 2, [], 3, [4, 5, 6], 7, 8, [9, 10]] end evaluate <<-ruby do @a = -> (a, (b, (c, *d, (e, (*f)), g), (h, (i, j)))) do [a, b, c, d, e, f, g, h, i, j] end ruby @a.(1, 2).should == [1, 2, nil, [], nil, [nil], nil, nil, nil, nil] result = @a.(1, [2, [3, 4, 5, [6, [7, 8]], 9], [10, [11, 12]]]) result.should == [1, 2, 3, [4, 5], 6, [7, 8], 9, 10, 11, 12] end evaluate <<-ruby do @a = -> (*, **k) { k } ruby @a.().should == {} @a.(1, 2, 3, a: 4, b: 5).should == {a: 4, b: 5} h = mock("keyword splat") h.should_receive(:to_hash).and_return({a: 1}) @a.(h).should == {a: 1} end evaluate <<-ruby do @a = -> (*, &b) { b } ruby @a.().should be_nil @a.(1, 2, 3, 4).should be_nil @a.(&(l = ->{})).should equal(l) end evaluate <<-ruby do @a = -> (a:, b:) { [a, b] } ruby @a.(a: 1, b: 2).should == [1, 2] end evaluate <<-ruby do @a = -> (a:, b: 1) { [a, b] } ruby @a.(a: 1).should == [1, 1] @a.(a: 1, b: 2).should == [1, 2] end evaluate <<-ruby do @a = -> (a: 1, b:) { [a, b] } ruby @a.(b: 0).should == [1, 0] @a.(b: 2, a: 3).should == [3, 2] end evaluate <<-ruby do @a = -> (a: @a = -> (a: 1) { a }, b:) do [a, b] end ruby @a.(a: 2, b: 3).should == [2, 3] @a.(b: 1).should == [@a, 1] # Note the default value of a: in the original method. @a.().should == 1 end evaluate <<-ruby do @a = -> (a: 1, b: 2) { [a, b] } ruby @a.().should == [1, 2] @a.(b: 3, a: 4).should == [4, 3] end evaluate <<-ruby do @a = -> (a, b=1, *c, (*d, (e)), f: 2, g:, h:, **k, &l) do [a, b, c, d, e, f, g, h, k, l] end ruby result = @a.(9, 8, 7, 6, f: 5, g: 4, h: 3, &(l = ->{})) result.should == [9, 8, [7], [], 6, 5, 4, 3, {}, l] end evaluate <<-ruby do @a = -> a, b=1, *c, d, e:, f: 2, g:, **k, &l do [a, b, c, d, e, f, g, k, l] end ruby result = @a.(1, 2, e: 3, g: 4, h: 5, i: 6, &(l = ->{})) result.should == [1, 1, [], 2, 3, 2, 4, { h: 5, i: 6 }, l] end describe "with circular optional argument reference" do it "shadows an existing local with the same name as the argument" do a = 1 -> { @proc = eval "-> (a=a) { a }" }.should complain(/circular argument reference/) @proc.call.should == nil end it "shadows an existing method with the same name as the argument" do def a; 1; end -> { @proc = eval "-> (a=a) { a }" }.should complain(/circular argument reference/) @proc.call.should == nil end it "calls an existing method with the same name as the argument if explicitly using ()" do def a; 1; end -> a=a() { a }.call.should == 1 end end end end describe "A lambda expression 'lambda { ... }'" do SpecEvaluate.desc = "for definition" it "calls the #lambda method" do obj = mock("lambda definition") obj.should_receive(:lambda).and_return(obj) def obj.define lambda { } end obj.define.should equal(obj) end it "does not execute the block" do lambda { fail }.should be_an_instance_of(Proc) end it "returns a lambda" do lambda { }.lambda?.should be_true end it "requires a block" do lambda { lambda }.should raise_error(ArgumentError) end ruby_version_is "2.5" do it "may include a rescue clause" do eval('lambda do raise ArgumentError; rescue ArgumentError; 7; end').should be_an_instance_of(Proc) end end context "with an implicit block" do before do def meth; lambda; end end ruby_version_is ""..."2.7" do it "can be created" do implicit_lambda = nil -> { implicit_lambda = meth { 1 } }.should complain(/tried to create Proc object without a block/) implicit_lambda.lambda?.should be_true implicit_lambda.call.should == 1 end end ruby_version_is "2.7" do it "raises ArgumentError" do implicit_lambda = nil -> { meth { 1 } }.should raise_error(ArgumentError, /tried to create Proc object without a block/) end end end context "assigns no local variables" do evaluate <<-ruby do @a = lambda { } @b = lambda { || } ruby @a.().should be_nil @b.().should be_nil end end context "assigns variables from parameters" do evaluate <<-ruby do @a = lambda { |a| a } ruby @a.(1).should == 1 end evaluate <<-ruby do def m(*a) yield(*a) end @a = lambda { |a| a } ruby lambda { m(&@a) }.should raise_error(ArgumentError) lambda { m(1, 2, &@a) }.should raise_error(ArgumentError) end evaluate <<-ruby do @a = lambda { |a, | a } ruby @a.(1).should == 1 @a.([1, 2]).should == [1, 2] lambda { @a.() }.should raise_error(ArgumentError) lambda { @a.(1, 2) }.should raise_error(ArgumentError) end evaluate <<-ruby do def m(a) yield a end def m2() yield end @a = lambda { |a, | a } ruby m(1, &@a).should == 1 m([1, 2], &@a).should == [1, 2] lambda { m2(&@a) }.should raise_error(ArgumentError) end evaluate <<-ruby do @a = lambda { |(a)| a } ruby @a.(1).should == 1 @a.([1, 2, 3]).should == 1 end evaluate <<-ruby do @a = lambda { |(*a, b)| [a, b] } ruby @a.(1).should == [[], 1] @a.([1, 2, 3]).should == [[1, 2], 3] end evaluate <<-ruby do @a = lambda { |a={}| a } ruby @a.().should == {} @a.(2).should == 2 end evaluate <<-ruby do @a = lambda { |*| } ruby @a.().should be_nil @a.(1).should be_nil @a.(1, 2, 3).should be_nil end evaluate <<-ruby do @a = lambda { |*a| a } ruby @a.().should == [] @a.(1).should == [1] @a.(1, 2, 3).should == [1, 2, 3] end evaluate <<-ruby do @a = lambda { |a:| a } ruby lambda { @a.() }.should raise_error(ArgumentError) @a.(a: 1).should == 1 end evaluate <<-ruby do @a = lambda { |a: 1| a } ruby @a.().should == 1 @a.(a: 2).should == 2 end evaluate <<-ruby do @a = lambda { |**| } ruby @a.().should be_nil @a.(a: 1, b: 2).should be_nil lambda { @a.(1) }.should raise_error(ArgumentError) end evaluate <<-ruby do @a = lambda { |**k| k } ruby @a.().should == {} @a.(a: 1, b: 2).should == {a: 1, b: 2} end evaluate <<-ruby do @a = lambda { |&b| b } ruby @a.().should be_nil @a.() { }.should be_an_instance_of(Proc) end evaluate <<-ruby do @a = lambda { |a, b| [a, b] } ruby @a.(1, 2).should == [1, 2] end evaluate <<-ruby do @a = lambda do |(a, b, *c, d), (*e, f, g), (*h)| [a, b, c, d, e, f, g, h] end ruby @a.(1, 2, 3).should == [1, nil, [], nil, [], 2, nil, [3]] result = @a.([1, 2, 3], [4, 5, 6, 7, 8], [9, 10]) result.should == [1, 2, [], 3, [4, 5, 6], 7, 8, [9, 10]] end evaluate <<-ruby do @a = lambda do |a, (b, (c, *d, (e, (*f)), g), (h, (i, j)))| [a, b, c, d, e, f, g, h, i, j] end ruby @a.(1, 2).should == [1, 2, nil, [], nil, [nil], nil, nil, nil, nil] result = @a.(1, [2, [3, 4, 5, [6, [7, 8]], 9], [10, [11, 12]]]) result.should == [1, 2, 3, [4, 5], 6, [7, 8], 9, 10, 11, 12] end evaluate <<-ruby do @a = lambda { |*, **k| k } ruby @a.().should == {} @a.(1, 2, 3, a: 4, b: 5).should == {a: 4, b: 5} h = mock("keyword splat") h.should_receive(:to_hash).and_return({a: 1}) @a.(h).should == {a: 1} end evaluate <<-ruby do @a = lambda { |*, &b| b } ruby @a.().should be_nil @a.(1, 2, 3, 4).should be_nil @a.(&(l = ->{})).should equal(l) end evaluate <<-ruby do @a = lambda { |a:, b:| [a, b] } ruby @a.(a: 1, b: 2).should == [1, 2] end evaluate <<-ruby do @a = lambda { |a:, b: 1| [a, b] } ruby @a.(a: 1).should == [1, 1] @a.(a: 1, b: 2).should == [1, 2] end evaluate <<-ruby do @a = lambda { |a: 1, b:| [a, b] } ruby @a.(b: 0).should == [1, 0] @a.(b: 2, a: 3).should == [3, 2] end evaluate <<-ruby do @a = lambda do |a: (@a = -> (a: 1) { a }), b:| [a, b] end ruby @a.(a: 2, b: 3).should == [2, 3] @a.(b: 1).should == [@a, 1] # Note the default value of a: in the original method. @a.().should == 1 end evaluate <<-ruby do @a = lambda { |a: 1, b: 2| [a, b] } ruby @a.().should == [1, 2] @a.(b: 3, a: 4).should == [4, 3] end evaluate <<-ruby do @a = lambda do |a, b=1, *c, (*d, (e)), f: 2, g:, h:, **k, &l| [a, b, c, d, e, f, g, h, k, l] end ruby result = @a.(9, 8, 7, 6, f: 5, g: 4, h: 3, &(l = ->{})) result.should == [9, 8, [7], [], 6, 5, 4, 3, {}, l] end evaluate <<-ruby do @a = lambda do |a, b=1, *c, d, e:, f: 2, g:, **k, &l| [a, b, c, d, e, f, g, k, l] end ruby result = @a.(1, 2, e: 3, g: 4, h: 5, i: 6, &(l = ->{})) result.should == [1, 1, [], 2, 3, 2, 4, { h: 5, i: 6 }, l] end end end