reversion

n 1: (law) an interest in an estate that reverts to the grantor

(or his heirs) at the end of some period (e.g., the

death of the grantee)

2: a reappearance of an earlier characteristic [syn: {atavism},

{throwback}]

3: turning in the opposite direction [syn: {reverse}, {reversal},

{turnabout}, {turnaround}]

4: returning to a former state [syn: {regression}, {regress}, {retrogression},

{retroversion}]

5: a failure to maintain a higher state [syn: {backsliding}, {lapse},

{lapsing}, {recidivism}, {relapse}, {relapsing}, {reverting}]

recursion

When a {function} (or {procedure})

calls itself. Such a function is called "recursive". If the

call is via one or more other functions then this group of

functions are called "mutually recursive".

If a function will always call itself, however it is called,

then it will never terminate. Usually however, it first

performs some test on its arguments to check for a "base case"

- a condition under which it can return a value without

calling itself.

The {canonical} example of a recursive function is

{factorial}:

factorial 0 ◦ 1

factorial n ◦ n ▫ factorial (n-1)

{Functional programming languages} rely heavily on recursion,

using it where a {procedural language} would use {iteration}.

See also {recursion}, {recursive definition}, {tail recursion}.

[{Jargon File}]

(1996-05-11)