listless

programming In functional programming, a property of a

function which allows it to be combined with other functions

in a way that eliminates intermediate data structures,

especially lists.

Phil Wadler's thesis gives the conditions for a function to

be in listless form: each input list is traversed only once,

one element at a time, from left to right. Each output list

is generated once, one element at a time, from left to right.

No other lists are generated or traversed.

Not all functions can be expressed in listless form

(e.g. reverse).

(1995-02-22)