ProcForCaseEquality.new { puts ‘procs in case statements are cool!’ }¶ ↑

Features¶ ↑

Simple yet powerful: it lets you use procs for case comparisons (see the example below).

How¶ ↑

case statements call the === method, so I wrote a ProcForCaseEquality class that inherits from Proc and overrides ===, letting the case statement call the proc passing the value of the case as argument.

The source code is so simple that I can put it in full here:

class ProcForCaseEquality < Proc
  def ===(*params)
    self.call *params
  end
end

5 LOCs :P

Installation¶ ↑

gem install proc_for_case_equality

Usage / Examples¶ ↑

require 'proc_for_case_equality' # OR:
require 'proc_for_case_equality/pfce' # if you want PFCE constant to point to ProcForCaseEquality

# Define some procs
all_multiples_of_3 = ProcForCaseEquality.new { |numbers| numbers.all? { |number| number.modulo(3).zero? } }
any_multiple_of_3  = PFCE.new { |numbers| numbers.any? { |number| number.modulo(3).zero? } } # PFCE is provided by 'proc_for_case_equality/pfce'

# Here we come
case [1, 2, 3]
when all_multiples_of_3 
  puts 'all numbers are multiples of 3'
when any_multiple_of_3
  puts 'at least one number is multiple of 3'
else
  puts 'no multiples of 3'
end

Inspired by¶ ↑

This article

License¶ ↑

MIT (see LICENSE)