Trivial Continuation Manual

[in package TRIVIAL-CONTINUATION]

Description

This library provides an implementation of function call continuation and combination.

Installing trivial-continuation

This project is available in the latest QuickLisp distribution, so installing it is reduced to calling:

(ql:quickload :trivial-continuation)

Working Example

(cc/define simple-continuation (seq)
  (if seq
      cc/create-return (car seq)
			#'(lambda () (simple-continuation (cdr seq)))
			:operation :combine)
      (cc/delegate)))

(let ((cont (combine-continuations (simple-continuation '(1 2 3 4))  
                                   (simple-continuation '(5 6 7 8)))))
  (format t \"~a\" (result cont))

  (setf cont (call-continuation cont))
  (format t \"~a\" (result cont)))

Exported Symbols

• [class] CONTINUATION-RESULT

  The CONTINUATION-RESULT class represents the result of a method, the continuation from it and the combination operation.

• [reader] RESULT CONTINUATION-RESULT (:RESULT = NIL)

  The RESULT slot carries the return value from calling a continuation.

• [reader] CONTINUATION CONTINUATION-RESULT (:CONTINUATION = NIL)

  The CONTINUATION slot holds the continuation function to be called next.

• [reader] OPERATION CONTINUATION-RESULT (:OPERATION = :TERMINATE)

  The OPERATION slot controls how two continuations are to be combined.
  Valid values are:
  :combine - the current continuation carries a valid result, and still other continuations should be called
  :delegate - the current continuation does not have any result, but still another continuation should be called
  :terminate - no further continuation shall be called

• [macro] CC/DEFINE (&REST ARGS) &BODY BODY

  Define a function to serve as a continuation.

• [macro] CC/RETURN RESULT

  Return the RESULT from inside of CC/DEFINE.

• [macro] CC/CREATE-RETURN VALUE CONTINUATION &KEY (OPERATION :COMBINE)

  Create a new result to be returned from inside CC/DEFINE.

• [macro] CC/DELEGATE

  Indicate that this does not carry any result, but instead a continuation should be called. Used inside of CC/DEFINE.

• [macro] CC/TERMINATE

  Indicate that this result should be the last in a chain. Used inside of CC/DEFINE.

• [function] CC/CONTINUE CONT

  Call the continuation of a CONTINUATION-RESULT, checking if one is defined and modifying CONT. Emits a warning when calling on an object with OPERATION :terminate.

• [generic-function] COMBINE-CONTINUATIONS HEAD TAIL

  Combine two continuations to form a new one. HEAD and TAIL can (independently) be CONTINUATION-RESULT or a function returning a CONTINUATION-RESULT

• [function] CALL-CONTINUATION CONT

  Call the continuation of a CONTINUATION-RESULT, checking if one is defined. Emits a warning when calling on an object with OPERATION :terminate.

• [function] FOLLOW-CHAIN RESULT

  Return whether RESULT has a valid continuation.

License Information

This library is released under the MIT License. Please refer to the LICENSE to get the full licensing text.

Contributing to this project

Please refer to the CONTRIBUTING document for more information.