22 lines
710 B
Plaintext
22 lines
710 B
Plaintext
(define-syntax with
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(syntax-rules
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"use a context manager. Takes a value, name and body
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and binds value to name in body. Ensures resource cleanup.
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params:
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- val: the value to bind
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- var: the name to bind to
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- body: varargs for the body
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complexity: O(1)
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returns: the result of the resource cleanup"()
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((_ val var body ...)
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(let ((var val))
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(begin
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body ...
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(teardown var))))))
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(defprotocol context-manager ((teardown 1)))
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(defimpl context-manager input-port? ((teardown close-input-file)))
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(defimpl context-manager output-port? ((teardown close-output-file)))
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(defimpl context-manager net:socket? ((teardown net:close-socket)))
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