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-rw-r--r--spec/ruby/language/if_spec.rb424
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diff --git a/spec/ruby/language/if_spec.rb b/spec/ruby/language/if_spec.rb
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+require_relative '../spec_helper'
+
+describe "The if expression" do
+ describe "accepts multiple assignments in conditional expression" do
+ before(:each) { ScratchPad.record([]) }
+ after(:each) { ScratchPad.clear }
+
+ it 'with non-nil values' do
+ ary = [1, 2]
+ eval "if (a, b = ary); ScratchPad.record [a, b]; end"
+ ScratchPad.recorded.should == [1, 2]
+ end
+
+ it 'with nil values' do
+ ary = nil
+ eval "if (a, b = ary); else; ScratchPad.record [a, b]; end"
+ ScratchPad.recorded.should == [nil, nil]
+ end
+ end
+
+ it "evaluates body if expression is true" do
+ a = []
+ if true
+ a << 123
+ end
+ a.should == [123]
+ end
+
+ it "does not evaluate body if expression is false" do
+ a = []
+ if false
+ a << 123
+ end
+ a.should == []
+ end
+
+ it "does not evaluate body if expression is empty" do
+ a = []
+ if ()
+ a << 123
+ end
+ a.should == []
+ end
+
+ it "does not evaluate else-body if expression is true" do
+ a = []
+ if true
+ a << 123
+ else
+ a << 456
+ end
+ a.should == [123]
+ end
+
+ it "evaluates only else-body if expression is false" do
+ a = []
+ if false
+ a << 123
+ else
+ a << 456
+ end
+ a.should == [456]
+ end
+
+ it "returns result of then-body evaluation if expression is true" do
+ if true
+ 123
+ end.should == 123
+ end
+
+ it "returns result of last statement in then-body if expression is true" do
+ if true
+ 'foo'
+ 'bar'
+ 'baz'
+ end.should == 'baz'
+ end
+
+ it "returns result of then-body evaluation if expression is true and else part is present" do
+ if true
+ 123
+ else
+ 456
+ end.should == 123
+ end
+
+ it "returns result of else-body evaluation if expression is false" do
+ if false
+ 123
+ else
+ 456
+ end.should == 456
+ end
+
+ it "returns nil if then-body is empty and expression is true" do
+ if true
+ end.should == nil
+ end
+
+ it "returns nil if then-body is empty, expression is true and else part is present" do
+ if true
+ else
+ 456
+ end.should == nil
+ end
+
+ it "returns nil if then-body is empty, expression is true and else part is empty" do
+ if true
+ else
+ end.should == nil
+ end
+
+ it "returns nil if else-body is empty and expression is false" do
+ if false
+ 123
+ else
+ end.should == nil
+ end
+
+ it "returns nil if else-body is empty, expression is false and then-body is empty" do
+ if false
+ else
+ end.should == nil
+ end
+
+ it "considers an expression with nil result as false" do
+ if nil
+ 123
+ else
+ 456
+ end.should == 456
+ end
+
+ it "considers a non-nil and non-boolean object in expression result as true" do
+ if mock('x')
+ 123
+ else
+ 456
+ end.should == 123
+ end
+
+ it "considers a zero integer in expression result as true" do
+ if 0
+ 123
+ else
+ 456
+ end.should == 123
+ end
+
+ it "allows starting else-body on the same line" do
+ if false
+ 123
+ else 456
+ end.should == 456
+ end
+
+ it "evaluates subsequent elsif statements and execute body of first matching" do
+ if false
+ 123
+ elsif false
+ 234
+ elsif true
+ 345
+ elsif true
+ 456
+ end.should == 345
+ end
+
+ it "evaluates else-body if no if/elsif statements match" do
+ if false
+ 123
+ elsif false
+ 234
+ elsif false
+ 345
+ else
+ 456
+ end.should == 456
+ end
+
+ it "allows 'then' after expression when then-body is on the next line" do
+ if true then
+ 123
+ end.should == 123
+
+ if true then ; 123; end.should == 123
+ end
+
+ it "allows then-body on the same line separated with 'then'" do
+ if true then 123
+ end.should == 123
+
+ if true then 123; end.should == 123
+ end
+
+ it "returns nil when then-body on the same line separated with 'then' and expression is false" do
+ if false then 123
+ end.should == nil
+
+ if false then 123; end.should == nil
+ end
+
+ it "returns nil when then-body separated by 'then' is empty and expression is true" do
+ if true then
+ end.should == nil
+
+ if true then ; end.should == nil
+ end
+
+ it "returns nil when then-body separated by 'then', expression is false and no else part" do
+ if false then
+ end.should == nil
+
+ if false then ; end.should == nil
+ end
+
+ it "evaluates then-body when then-body separated by 'then', expression is true and else part is present" do
+ if true then 123
+ else 456
+ end.should == 123
+
+ if true then 123; else 456; end.should == 123
+ end
+
+ it "evaluates else-body when then-body separated by 'then' and expression is false" do
+ if false then 123
+ else 456
+ end.should == 456
+
+ if false then 123; else 456; end.should == 456
+ end
+
+ describe "with a boolean range ('flip-flop' operator)" do
+ before :each do
+ ScratchPad.record []
+ end
+
+ after :each do
+ ScratchPad.clear
+ end
+
+ it "mimics an awk conditional with a single-element inclusive-end range" do
+ 10.times { |i| ScratchPad << i if (i == 4)..(i == 4) }
+ ScratchPad.recorded.should == [4]
+ end
+
+ it "mimics an awk conditional with a many-element inclusive-end range" do
+ 10.times { |i| ScratchPad << i if (i == 4)..(i == 7) }
+ ScratchPad.recorded.should == [4, 5, 6, 7]
+ end
+
+ it "mimics a sed conditional with a zero-element exclusive-end range" do
+ eval "10.times { |i| ScratchPad << i if (i == 4)...(i == 4) }"
+ ScratchPad.recorded.should == [4, 5, 6, 7, 8, 9]
+ end
+
+ it "mimics a sed conditional with a many-element exclusive-end range" do
+ 10.times { |i| ScratchPad << i if (i == 4)...(i == 5) }
+ ScratchPad.recorded.should == [4, 5]
+ end
+
+ it "allows combining two flip-flops" do
+ 10.times { |i| ScratchPad << i if (i == 4)...(i == 5) or (i == 7)...(i == 8) }
+ ScratchPad.recorded.should == [4, 5, 7, 8]
+ end
+
+ it "evaluates the first conditions lazily with inclusive-end range" do
+ collector = proc { |i| ScratchPad << i }
+ eval "10.times { |i| i if collector[i]...false }"
+ ScratchPad.recorded.should == [0]
+ end
+
+ it "evaluates the first conditions lazily with exclusive-end range" do
+ collector = proc { |i| ScratchPad << i }
+ eval "10.times { |i| i if collector[i]..false }"
+ ScratchPad.recorded.should == [0]
+ end
+
+ it "evaluates the second conditions lazily with inclusive-end range" do
+ collector = proc { |i| ScratchPad << i }
+ 10.times { |i| i if (i == 4)...collector[i] }
+ ScratchPad.recorded.should == [5]
+ end
+
+ it "evaluates the second conditions lazily with exclusive-end range" do
+ collector = proc { |i| ScratchPad << i }
+ 10.times { |i| i if (i == 4)..collector[i] }
+ ScratchPad.recorded.should == [4]
+ end
+
+ it "scopes state by flip-flop" do
+ store_me = proc { |i| ScratchPad << i if (i == 4)..(i == 7) }
+ store_me[1]
+ store_me[4]
+ proc { store_me[1] }.call
+ store_me[7]
+ store_me[5]
+ ScratchPad.recorded.should == [4, 1, 7]
+ end
+
+ it "keeps flip-flops from interfering" do
+ a = eval "proc { |i| ScratchPad << i if (i == 4)..(i == 7) }"
+ b = eval "proc { |i| ScratchPad << i if (i == 4)..(i == 7) }"
+ 6.times(&a)
+ 6.times(&b)
+ ScratchPad.recorded.should == [4, 5, 4, 5]
+ end
+
+ it "warns when Integer literals are used instead of predicates" do
+ -> {
+ eval <<~RUBY
+ $. = 0
+ 10.times { |i| ScratchPad << i if 4..5 }
+ RUBY
+ }.should complain(/warning: integer literal in flip-flop/, verbose: true)
+ ScratchPad.recorded.should == []
+ end
+ end
+
+ describe "when a branch syntactically does not return a value" do
+ it "raises SyntaxError if both do not return a value" do
+ -> {
+ eval <<~RUBY
+ def m
+ a = if rand
+ return
+ else
+ return
+ end
+ a
+ end
+ RUBY
+ }.should.raise(SyntaxError, /void value expression/)
+ end
+
+ it "does not raise SyntaxError if one branch returns a value" do
+ eval(<<~RUBY).should == 1
+ def m
+ a = if false # using false to make it clear that's not checked for
+ 42
+ else
+ return 1
+ end
+ a
+ end
+ m
+ RUBY
+
+ eval(<<~RUBY).should == 1
+ def m
+ a = if true # using true to make it clear that's not checked for
+ return 1
+ else
+ 42
+ end
+ a
+ end
+ m
+ RUBY
+ end
+ end
+end
+
+describe "The postfix if form" do
+ it "evaluates statement if expression is true" do
+ a = []
+ a << 123 if true
+ a.should == [123]
+ end
+
+ it "does not evaluate statement if expression is false" do
+ a = []
+ a << 123 if false
+ a.should == []
+ end
+
+ it "returns result of expression if value is true" do
+ (123 if true).should == 123
+ end
+
+ it "returns nil if expression is false" do
+ (123 if false).should == nil
+ end
+
+ it "considers a nil expression as false" do
+ (123 if nil).should == nil
+ end
+
+ it "considers a non-nil object as true" do
+ (123 if mock('x')).should == 123
+ end
+
+ it "evaluates then-body in containing scope" do
+ a = 123
+ if true
+ b = a+1
+ end
+ b.should == 124
+ end
+
+ it "evaluates else-body in containing scope" do
+ a = 123
+ if false
+ b = a+1
+ else
+ b = a+2
+ end
+ b.should == 125
+ end
+
+ it "evaluates elsif-body in containing scope" do
+ a = 123
+ if false
+ b = a+1
+ elsif false
+ b = a+2
+ elsif true
+ b = a+3
+ else
+ b = a+4
+ end
+ b.should == 126
+ end
+end
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