Data.Bool.Compat

otherwise is defined as the value True. It helps to make guards more readable. eg.

 f x | x < 0     = ...
     | otherwise = ...

Boolean "and", lazy in the second argument

Boolean "not"

Boolean "or", lazy in the second argument

Case analysis for the Bool type. bool f t p evaluates to f when p is False, and evaluates to t when p is True.

This is equivalent to if p then t else f; that is, one can think of it as an if-then-else construct with its arguments reordered.

Examples

Basic usage:

>>> bool "foo" "bar" True"bar">>> bool "foo" "bar" False"foo"

Confirm that bool f t p and if p then t else f are equivalent:

>>> let p = True; f = "bar"; t = "foo">>> bool f t p == if p then t else fTrue>>> let p = False>>> bool f t p == if p then t else fTrue