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| <h5 class="subsubsection">23.3.3.20 Guile representation of lazy strings.</h5> |
| |
| <p><a name="index-lazy-strings-in-guile-2804"></a><a name="index-g_t_003cgdb_003alazy_002dstring_003e-2805"></a> |
| A <dfn>lazy string</dfn> is a string whose contents is not retrieved or |
| encoded until it is needed. |
| |
| <p>A <code><gdb:lazy-string></code> is represented in <span class="sc">gdb</span> as an |
| <code>address</code> that points to a region of memory, an <code>encoding</code> |
| that will be used to encode that region of memory, and a <code>length</code> |
| to delimit the region of memory that represents the string. The |
| difference between a <code><gdb:lazy-string></code> and a string wrapped within |
| a <code><gdb:value></code> is that a <code><gdb:lazy-string></code> will be treated |
| differently by <span class="sc">gdb</span> when printing. A <code><gdb:lazy-string></code> is |
| retrieved and encoded during printing, while a <code><gdb:value></code> |
| wrapping a string is immediately retrieved and encoded on creation. |
| |
| <p>The following lazy-string-related procedures are provided by the |
| <code>(gdb)</code> module: |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>lazy-string?</b><var> object<a name="index-lazy_002dstring_003f-2806"></a></var><br> |
| <blockquote><p>Return <code>#t</code> if <var>object</var> is an object of type <code><gdb:lazy-string></code>. |
| Otherwise return <code>#f</code>. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>lazy-string-address</b><var> lazy-sring<a name="index-lazy_002dstring_002daddress-2807"></a></var><br> |
| <blockquote><p>Return the address of <var>lazy-string</var>. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>lazy-string-length</b><var> lazy-string<a name="index-lazy_002dstring_002dlength-2808"></a></var><br> |
| <blockquote><p>Return the length of <var>lazy-string</var> in characters. If the |
| length is -1, then the string will be fetched and encoded up to the |
| first null of appropriate width. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>lazy-string-encoding</b><var> lazy-string<a name="index-lazy_002dstring_002dencoding-2809"></a></var><br> |
| <blockquote><p>Return the encoding that will be applied to <var>lazy-string</var> |
| when the string is printed by <span class="sc">gdb</span>. If the encoding is not |
| set, or contains an empty string, then <span class="sc">gdb</span> will select the |
| most appropriate encoding when the string is printed. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>lazy-string-type</b><var> lazy-string<a name="index-lazy_002dstring_002dtype-2810"></a></var><br> |
| <blockquote><p>Return the type that is represented by <var>lazy-string</var>'s type. |
| For a lazy string this is a pointer or array type. To |
| resolve this to the lazy string's character type, use <code>type-target-type</code>. |
| See <a href="Types-In-Guile.html#Types-In-Guile">Types In Guile</a>. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>lazy-string->value</b><var> lazy-string<a name="index-lazy_002dstring_002d_003evalue-2811"></a></var><br> |
| <blockquote><p>Convert the <code><gdb:lazy-string></code> to a <code><gdb:value></code>. This value |
| will point to the string in memory, but will lose all the delayed |
| retrieval, encoding and handling that <span class="sc">gdb</span> applies to a |
| <code><gdb:lazy-string></code>. |
| </p></blockquote></div> |
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