require_relative '../spec_helper' # for name[, name]... in expr [do] # body # end describe "The for expression" do it "iterates over an Enumerable passing each element to the block" do j = 0 for i in 1..3 j += i end j.should == 6 end it "iterates over a list of arrays and destructures with empty comma" do for i, in [[1,2]] i.should == 1 end end it "iterates over an Hash passing each key-value pair to the block" do k = 0 l = 0 for i, j in { 1 => 10, 2 => 20 } k += i l += j end k.should == 3 l.should == 30 end it "iterates over any object responding to 'each'" do class XYZ def each (0..10).each { |i| yield i } end end j = 0 for i in XYZ.new j += i end j.should == 55 end it "allows an instance variable as an iterator name" do m = [1,2,3] n = 0 for @var in m n += 1 end @var.should == 3 n.should == 3 end it "allows a class variable as an iterator name" do class OFor m = [1,2,3] n = 0 for @@var in m n += 1 end @@var.should == 3 n.should == 3 end end it "allows a constant as an iterator name" do class OFor m = [1,2,3] n = 0 -> { for CONST in m n += 1 end }.should complain(/already initialized constant/) CONST.should == 3 n.should == 3 end end # 1.9 behaviour verified by nobu in # http://redmine.ruby-lang.org/issues/show/2053 it "yields only as many values as there are arguments" do class OFor def each [[1,2,3], [4,5,6]].each do |a| yield(a[0],a[1],a[2]) end end end o = OFor.new qs = [] for q in o qs << q end qs.should == [1, 4] q.should == 4 end it "optionally takes a 'do' after the expression" do j = 0 for i in 1..3 do j += i end j.should == 6 end it "allows body begin on the same line if do is used" do j = 0 for i in 1..3 do j += i end j.should == 6 end it "executes code in containing variable scope" do for i in 1..2 a = 123 end a.should == 123 end it "executes code in containing variable scope with 'do'" do for i in 1..2 do a = 123 end a.should == 123 end it "returns expr" do for i in 1..3; end.should == (1..3) for i,j in { 1 => 10, 2 => 20 }; end.should == { 1 => 10, 2 => 20 } end it "breaks out of a loop upon 'break', returning nil" do j = 0 for i in 1..3 j += i break if i == 2 end.should == nil j.should == 3 end it "allows 'break' to have an argument which becomes the value of the for expression" do for i in 1..3 break 10 if i == 2 end.should == 10 end it "starts the next iteration with 'next'" do j = 0 for i in 1..5 next if i == 2 j += i end j.should == 13 end it "repeats current iteration with 'redo'" do j = 0 for i in 1..3 j += i redo if i == 2 && j < 4 end j.should == 8 end end