PHP array handling is, frankly, horrible; array_filter is cumbersome, and there is no list comprehension all together. This code is a proof of concept for list comprehension in PHP, written in PHP, for a number of elementary operations. The syntax is essentially, Haskell-like syntactic sugar, for PHP's iteration, array_filter, and creating new arrays. The code is hacky and horrible itself, and if done properly would include a parser, or some proper syntactic analysis. If I get time I'll rewrite it properly.

The syntax for the comprehension is as follows:

[x | x <- [n..m], predicate]

Which can be read as: the set of all xs, such that x is drawn from the list ranging from n to m, and which satisfy the predicate. The predicate is optional, allowing simple list creation.

[x | x <- [n..m]]

The current predicates/operations supported are equality, greater than, less than, division, addition, subtraction and modulo artithmetic.

Simply include lc.php and then use the lc procedure.

lc("[x | x <- [1..5]]")

[1, 2, 3, 4, 5]

lc("[x | x <- [10..20], x mod 2]")

[0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0]

lc("[x | x <- [1..5], x == 1]")

[1]

lc("[x | x <- [1..5], x <= 2]")

[1, 2]

lc("[x | x <- [20..22], x + 1]")

[21, 22, 23]