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;; SPDX-License-Identifier: EUPL-1.2
;; SPDX-FileCopyrightText: 2025 Uko Kokņevičs <perkontevs@gmail.com>
(defpackage :ukkoclot/src/streams
(:documentation "Stream-oriented utilities.")
(:import-from :serapeum :-> :with-thunk)
(:use :c2cl)
(:export :call-with-format-like-stream :with-format-like-stream))
(in-package :ukkoclot/src/streams)
(-> call-with-format-like-stream ((or stream boolean) (function (stream) t)) t)
(defun call-with-format-like-stream (stream-spec fn)
"Similar to `with-format-like-stream', but instead of binding the translated stream in a macro body,
calls the function `fn' with it."
(case stream-spec
((t) (funcall fn *standard-output*) nil)
((nil) (with-output-to-string (stream) (funcall fn stream)))
(otherwise (funcall fn stream-spec) nil)))
(defmacro with-format-like-stream ((stream-out stream-spec) &body body)
"Translates the `stream-spec' into a `stream' similar to how `format' does it and binds it as `stream-out' in `body'.
If `stream-spec' is `t': Output to `*standard-output*' and return `nil'.
If `stream-spec' is `nil': Output to a string and return it.
Else: `stream-spec' must be a stream, output to it and return `nil'"
(with-thunk (body stream-out)
`(call-with-format-like-stream ,stream-spec ,body)))
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