call-with-port -- r7rs Definition

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Kind

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procedure;

Implemented by

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• call-with-port (from vonuvoli);

Procedure signature

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Procedure variants:

• ((port procedure-1) -> (any))
  • inputs:
    • a value of type port;
    • a value of type procedure-1;
  • output: a value of type any;

Exports

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• scheme:base -- (scheme base);

Exports recursive

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• scheme -- (scheme);

Description

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(call-with-port port proc)

Domain: It is an error if proc does not accept one argument.

The call-with-port procedure calls proc with port as an argument. If proc returns, then the port is closed automatically and the values yielded by the proc are returned. If proc does not return, then the port must not be closed automatically unless it is possible to prove that the port will never again be used for a read or write operation.

Rationale: Because Scheme's escape procedures have unlimited extent, it is possible to escape from the current continuation but later to resume it. If implementations were permitted to close the port on any escape from the current continuation, then it would be impossible to write portable code using both call-with-current-continuation and call-with-port.

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

Referenced-types

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• port;
• procedure-1;
• any;