ruby-lc is a lazy list comprehension libray, that tries to ressemble Haskell sintax.

Rigth now it only works with numbers, (but it may also works with something else that ducktype like a number)

For creating a comprehension list just call the CL method with a block, declaring the variables you want to use, as the block's parameters and define the list comprehension expressions inside an Array, like this:

CL {|x| [ x , x << (0..10), x % 2 == 0 ]}

The call to CL, returns an Enumerator which can be used to access the comprehension list's values.

The first element in the Array must always be an expression, the remainder elements may be boolean conditions, or the variable's binding expressions, which uses this sintax: <variable> << <Enumerable>, where << pretends to behave like Haskell's <-.

  
Some examples:

LC {|x,y| [x + y, y << (0..20), x << (1..10), y % 7 == 0, x % 2 == 1  ]}.to_a

#[1, 3, 5, 7, 9, 8, 10, 12, 14, 16, 15, 17, 19, 21, 23]


LC {|x| [x, x << LC::Nat, x > 6, (x % 6 == 1) | (x % 6 == 5) ] }.take 100

#whichs returns the first 100 natural numbers than are congruent 1 or 5 modulo 6, greater than 6.


LC {|x| [x ** 2 , x <<  LC::Nat ,x > 100 , LC.func(:prime?, x) ] }.take 10

#the squares of the first 10 primes numbers above 100 (prime? has to be a 'top-level function')