nu.engine.validation.predicate

Module nu.engine.validation.predicate.

Predicate: a composable (program, path) -> bool test.

• Test is the callable shape -- any (program, path) -> bool function. It is what laws ultimately consume; nothing more.
• Predicate wraps a Test to give it an algebra: &, |, and ~ combine predicates without forcing the caller to nest lambdas. The right operand of a binary combinator may be any bare Test -- the result is always a Predicate.

Wrap a plain function with the @predicate decorator to give it the same algebra. Predicates are the building block for Law.scope and Law.holds.

predicate

Wrap a (program, path) -> bool function as a composable Predicate.

lang.predicate(test)

Path nu.lang.predicate. Defined on nu.engine.validation.predicate, bound as a function. Builds Predicate.

Arguments

Undocumented: example.