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Tail recursion

When the last thing a function (or procedure) does is to call itself. Such a function is called tail recursive. A function may make several recursive calls but a call is only tail-recursive if the caller returns immediately after it. E.g.
f n = if n < 2 then 1 else f (f (n-2) + 1) In this example both calls to f are recursive but only the outer one is tail recursive. Tail recursion is a useful property because it enables tail recursion optimisation. If you aren't sick of them already, see recursion and tail recursion. [Jargon File] (2006-04-16)


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    programming, compiler A generalisation of tail recursion introduced by D.H.D. Warren. It applies when the last thing a function does is to apply a constructor functions (e.g. cons) to an application of a non-primitive function. This is transformed into a tail call to the function which is also passed a pointer to where its result […]

  • Tail recursion optimisation

    programming (TRO) Discarding the calling environment (call stack frame) when the last thing a function or procedure does is to call itself. This is important when a procedure calls itself recursively many times since, without tail recursion optimisation, the environments of earlier invocations would fill up the memory only to be discarded when (if) the […]

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  • Tails

    adjective, adverb 1. (of a coin) with the reverse facing up: On the next toss, the coin came up tails. Compare heads. noun 2. tail1 (def 6). noun 1. the hindmost part of an animal, especially that forming a distinct, flexible appendage to the trunk. 2. something resembling or suggesting this in shape or position: […]

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