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require_relative '../spec_helper'
describe "The '&&' statement" do
it "short-circuits evaluation at the first condition to be false" do
x = nil
true && false && x = 1
x.should be_nil
end
it "evaluates to the first condition not to be true" do
value = nil
(value && nil).should == nil
(value && false).should == nil
value = false
(value && nil).should == false
(value && false).should == false
("yes" && 1 && nil && true).should == nil
("yes" && 1 && false && true).should == false
end
it "evaluates to the last condition if all are true" do
("yes" && 1).should == 1
(1 && "yes").should == "yes"
end
it "evaluates the full set of chained conditions during assignment" do
x, y = nil
x = 1 && y = 2
# "1 && y = 2" is evaluated and then assigned to x
x.should == 2
end
it "treats empty expressions as nil" do
(() && true).should be_nil
(true && ()).should be_nil
(() && ()).should be_nil
end
end
describe "The 'and' statement" do
it "short-circuits evaluation at the first condition to be false" do
x = nil
true and false and x = 1
x.should be_nil
end
it "evaluates to the first condition not to be true" do
value = nil
(value and nil).should == nil
(value and false).should == nil
value = false
(value and nil).should == false
(value and false).should == false
("yes" and 1 and nil and true).should == nil
("yes" and 1 and false and true).should == false
end
it "evaluates to the last condition if all are true" do
("yes" and 1).should == 1
(1 and "yes").should == "yes"
end
it "when used in assignment, evaluates and assigns expressions individually" do
x, y = nil
x = 1 and y = 2
# evaluates (x=1) and (y=2)
x.should == 1
end
it "treats empty expressions as nil" do
(() and true).should be_nil
(true and ()).should be_nil
(() and ()).should be_nil
end
end
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