Module: BLazy

Defined in:
lib/b-lazy.rb

Class Method Summary collapse

Class Method Details

.when_needed(&f) ⇒ Object

Occassionally, we find that it is necessary to compute all values upfront before the enumeration. For example, if we are extracting lines from a file, then we might decide that guaranteeing that the file is closed cleanly is more important than lazily enumerating.

This function serves as a compromise: compute all of the values, but only do so if I attempt to enumerate over them.



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# File 'lib/b-lazy.rb', line 367

def when_needed(&f)
  Enumerator.new do |out|
    values = f.call
    values.each{|v| out.yield v}
  end
end