Description

A straightforward implementation of "futures" for concurrent evaluation of expressions.

Author

Felix

Version

Usage

(require-extension futures)

Download

futures.egg

Documentation

This extension provides syntax and data types for futures - concurrently evaluated expressions that memoize their result

macro: (future EXPRESSION)

Starts evaluation of EXPRESSION in a separate thread and returns a future object representing the computation.

procedure: (future? X)

Returns #t if X is an object returned by a future expression or #f otherwise.

procedure: (force X)

If X is a future, then the current threads waits until the expression evaluated at the point of creating the future is complete. If an error occurred during that evaluation, or when the future executed to completion, then force will return the result(s) of the future expression.

If the argument is not a future, then the usual semantics of force apply.

procedure: (future-complete? FUTURE)

Returns #t if the future has completed execution, or if an exception occurred during its evaluation, or #f otherwise.

procedure: (future-failed? FUTURE)

Returns #t if an exception occurred during evaluation of the future or #f otherwise.

procedure: (future-condition FUTURE)

Returns the error-condition if an exception occurred during evaluation of the future or #f if the future is still executing or executed without an error.

License

Copyright (c) 2005, Felix L. Winkelmann.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

  Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer. Redistributions in
  binary form must reproduce the above copyright notice, this list of
  conditions and the following disclaimer in the documentation and/or
  other materials provided with the distribution. Neither the name of the
  author nor the names of its contributors may be used to endorse or
  promote products derived from this software without specific prior
  written permission.

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