delay-force -- r7rs Definition

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Kind

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syntax;

Implemented by

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• delay-force (from vonuvoli);

Syntax signature

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Syntax keywords:

• expression: expression;

Syntax variants:

• (_ expression)

Exports

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• scheme:lazy -- (scheme lazy);

Exports recursive

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• scheme -- (scheme);

Description

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(delay-force <expression>)

Semantics: The expression (delay-force expression) is conceptually similar to (delay (force expression)), with the difference that forcing the result of delay-force will in effect result in a tail call to (force expression), while forcing the result of (delay (force expression)) might not. Thus iterative lazy algorithms that might result in a long series of chains of delay and force can be rewritten using delay-force to prevent consuming unbounded space during evaluation.

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The text herein was sourced and adapted as described in the "R7RS attribution of various text snippets" appendix.