Class: Mon::Monad::Lazy

Inherits:
Mon::Monad show all
Includes:
ChainableMonad
Defined in:
lib/monads/lazy.rb

Overview

Lazy is the parent class of Pending and Final, the two states a Lazy monad can be in. Use with: lazyValue = Lazy[5] # Seems pointless so far... lazyCalc = lazyValue.bind { |i| (0..i).map { |n| n.factorial } }.bind { |factlist| factlist.map { |i| i * i }.... # Keep right on going! # We still haven't done any work! puts lazyCalc.unwrap # Time to have a nap... Or: lazyProc = Lazy.eventually(5) { (0..5).map { |i| call_some_remote_service_ondemand(i) } } # Haven’t done anything yet… lazyProc.sample.unwrap.map { |v| “A random response: #{ v }” } # Do one of 5 possible service calls</tt>

Direct Known Subclasses

Final, Pending

Class Method Summary collapse

Methods included from ChainableMonad

#_, #coerce, #method_missing, #respond_to?

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class Mon::Monad::ChainableMonad

Class Method Details

.[](obj = nil) ⇒ Object

Wrap a value in Lazy



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# File 'lib/monads/lazy.rb', line 38

def self::[](obj = nil)
  if obj.is_a? Proc
    eventually(obj)
  else
    Final[obj]
  end
end

.eventually(*args, &fun) ⇒ Object

Perform an operation, if necessary: Lazy.eventually { 10 * 10 } Or: Lazy.eventually(10) { |n| n * 10 }



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# File 'lib/monads/lazy.rb', line 50

def self::eventually(*args, &fun)
  Pending::eventually(fun, args)
end

.valid?(v) ⇒ Boolean

For contracts. Deprecated!

Returns:

  • (Boolean) 


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# File 'lib/monads/lazy.rb', line 55

def self::valid?(v)
  v.is_a? Mon::Lazy
end