To enable developers to write neat, compact code, Many classes take advantage of implementing their own versions of '==='.
The '===’ operator is known as the case equality operator.
The '===’ operator is used when testing cases in case statements.
for each 'when' statement the '===' operator is called on the when argument (1,2..10,String) and the case argument (number) is used for the comparison. For line 5 the comparison done shall be '1 === number'.
For most classes ‘===’ is just an alias to ‘==’ however some classes redefine ‘===’ to allow for better functionality in case statements.
In Ruby a Proc is a block of executable code, an anonymous function which can be passed around as if it were data. Like ‘===’, a Proc can map a number of arguments to either a true or false value.
Simple Factorial lambda function in Ruby
def test_object number case number when Fixnum case number when 1 puts "It's One" when 2..10 puts "Between two and ten" else puts "-- #{number} -- is not between one and ten" end when String puts "You passed a string" else "I have no idea what to do with -- #{number} --" end end
is_weekday = lambda {|day_of_week, time| time.wday == day_of_week}.curry sunday = is_weekday[0] monday = is_weekday[1] tuesday = is_weekday[2] wednesday = is_weekday[3] thursday = is_weekday[4] friday = is_weekday[5] saturday = is_weekday[6] case Time.now when sunday puts "Day of rest" when monday, tuesday, wednesday, thursday, friday puts "Work" when saturday puts "Happy" end
factorial = lambda do |n| n <= 1 ? 1 : (n * factorial.call(n - 1)) end factorial.call 3
No comments:
Post a Comment