133 lines
6.6 KiB
HTML
133 lines
6.6 KiB
HTML
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Copyright (C) 1996-1997, 2000-2005, 2009-2023 Free Software Foundation,
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Copyright (C) 2021 Maxime Devos
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Copyright (C) 2024 Tomas Volf
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<title>Buffered Input (Guile Reference Manual)</title>
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<div class="section-level-extent" id="Buffered-Input">
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<p>
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Next: <a href="Expect.html" accesskey="n" rel="next">Expect</a>, Previous: <a href="Streams.html" accesskey="p" rel="prev">Streams</a>, Up: <a href="Guile-Modules.html" accesskey="u" rel="up">Guile Modules</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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<hr>
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<h3 class="section" id="Buffered-Input-1"><span>7.15 Buffered Input<a class="copiable-link" href="#Buffered-Input-1"> ¶</a></span></h3>
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<a class="index-entry-id" id="index-Buffered-input"></a>
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<a class="index-entry-id" id="index-Line-continuation"></a>
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<p>The following functions are provided by
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</p>
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<div class="example">
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<pre class="example-preformatted">(use-modules (ice-9 buffered-input))
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</pre></div>
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<p>A buffered input port allows a reader function to return chunks of
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characters which are to be handed out on reading the port. A notion
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of further input for an application level logical expression is
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maintained too, and passed through to the reader.
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</p>
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<dl class="first-deffn">
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<dt class="deffn" id="index-make_002dbuffered_002dinput_002dport"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">make-buffered-input-port</strong> <var class="def-var-arguments">reader</var><a class="copiable-link" href="#index-make_002dbuffered_002dinput_002dport"> ¶</a></span></dt>
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<dd><p>Create an input port which returns characters obtained from the given
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<var class="var">reader</var> function. <var class="var">reader</var> is called (<var class="var">reader</var> cont),
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and should return a string or an EOF object.
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</p>
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<p>The new port gives precisely the characters returned by <var class="var">reader</var>,
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nothing is added, so if any newline characters or other separators are
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desired they must come from the reader function.
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</p>
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<p>The <var class="var">cont</var> parameter to <var class="var">reader</var> is <code class="code">#f</code> for initial
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input, or <code class="code">#t</code> when continuing an expression. This is an
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application level notion, set with
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<code class="code">set-buffered-input-continuation?!</code> below. If the user has
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entered a partial expression then it allows <var class="var">reader</var> for instance
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to give a different prompt to show more is required.
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-make_002dline_002dbuffered_002dinput_002dport"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">make-line-buffered-input-port</strong> <var class="def-var-arguments">reader</var><a class="copiable-link" href="#index-make_002dline_002dbuffered_002dinput_002dport"> ¶</a></span></dt>
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<dd><a class="index-entry-id" id="index-Line-buffered-input"></a>
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<p>Create an input port which returns characters obtained from the
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specified <var class="var">reader</var> function, similar to
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<code class="code">make-buffered-input-port</code> above, but where <var class="var">reader</var> is
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expected to be a line-oriented.
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</p>
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<p><var class="var">reader</var> is called (<var class="var">reader</var> cont), and should return a string
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or an EOF object as above. Each string is a line of input without a
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newline character, the port code inserts a newline after each string.
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-set_002dbuffered_002dinput_002dcontinuation_003f_0021"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">set-buffered-input-continuation?!</strong> <var class="def-var-arguments">port cont</var><a class="copiable-link" href="#index-set_002dbuffered_002dinput_002dcontinuation_003f_0021"> ¶</a></span></dt>
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<dd><p>Set the input continuation flag for a given buffered input
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<var class="var">port</var>.
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</p>
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<p>An application uses this by calling with a <var class="var">cont</var> flag of
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<code class="code">#f</code> when beginning to read a new logical expression. For
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example with the Scheme <code class="code">read</code> function (see <a class="pxref" href="Scheme-Read.html">Reading Scheme Code</a>),
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</p>
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<div class="example">
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<pre class="example-preformatted">(define my-port (make-buffered-input-port my-reader))
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(set-buffered-input-continuation?! my-port #f)
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(let ((obj (read my-port)))
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...
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</pre></div>
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</dd></dl>
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</div>
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<hr>
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<div class="nav-panel">
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<p>
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Next: <a href="Expect.html">Expect</a>, Previous: <a href="Streams.html">Streams</a>, Up: <a href="Guile-Modules.html">Guile Modules</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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