higher-order macro

A means of expressing certain higher-order functions in a

first order language. Proposed by Phil Wadler. Higher-order

macros cannot be recursive at the top level but they may

contain recursive definitions. E.g.

map f l = m l

where

m [] = []

m (x:xs) = f x : m xs

Expanding a call to this macro is equivalent to specialising a

call to map in its first argument.

See partial evaluation.