mthl
/
texinfo


			
				
					
						
						
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227
							<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:pls="http://www.w3.org/2005/01/pronunciation-lexicon" xmlns:ssml="http://www.w3.org/2001/10/synthesis" xmlns:svg="http://www.w3.org/2000/svg">
  <head>
    <title>Deprecated low-level functions</title>
    <link rel="stylesheet" type="text/css" href="docbook-epub.css"/>
    <link rel="stylesheet" type="text/css" href="kawa.css"/>
    <script src="kawa-ebook.js" type="text/javascript"/>
    <meta name="generator" content="DocBook XSL-NS Stylesheets V1.79.1"/>
    <link rel="prev" href="Time-related-functions.xhtml" title="Time-related functions"/>
    <link rel="next" href="FAQs.xhtml" title="Frequently Asked Questions"/>
  </head>
  <body>
    <header/>
    <section class="sect1" title="Deprecated low-level functions" epub:type="subchapter" id="Low-level-functions">
      <div class="titlepage">
        <div>
          <div>
            <h2 class="title" style="clear: both">Deprecated low-level functions</h2>
          </div>
        </div>
      </div>
      <p>These sections document older and less convenient ways
to call Java methods, access Java fields, and use Java arrays.
</p>
      <span id="Low-level-Method-invocation"/>
      <section class="sect2" title="Low-level Method invocation" epub:type="division" id="idm139667869304896">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title">Low-level Method invocation</h3>
            </div>
          </div>
        </div>
        <p>The following lower-level primitives require you to specify
the parameter and return types explicitly.
You should probably use the functions <code class="literal">invoke</code> and <code class="literal">invoke-static</code>
(see <a class="link" href="Method-operations.xhtml" title="Calling Java methods from Scheme">Method operations</a>) instead.
</p>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869301648" class="indexterm"/> <code class="function">primitive-constructor</code> <em class="replaceable"><code>class</code></em> (<em class="replaceable"><code>argtype</code></em> <em class="replaceable"><code>...</code></em>)</p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Returns a new anonymous procedure, which when called will create
a new object of the specified class, and will then call the
constructor matching the specified argument types.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869297184" class="indexterm"/> <code class="function">primitive-virtual-method</code> <em class="replaceable"><code>class</code></em> <em class="replaceable"><code>method</code></em> <em class="replaceable"><code>rtype</code></em> (<em class="replaceable"><code>argtype</code></em> <em class="replaceable"><code>...</code></em>)</p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Returns a new anonymous procedure, which when called will
invoke the instance method whose name is the string <em class="replaceable"><code>method</code></em>
in the class whose name is <em class="replaceable"><code>class</code></em>.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869291040" class="indexterm"/> <code class="function">primitive-static-method</code> <em class="replaceable"><code>class</code></em> <em class="replaceable"><code>method</code></em> <em class="replaceable"><code>rtype</code></em> (<em class="replaceable"><code>argtype</code></em> <em class="replaceable"><code>...</code></em>)</p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Returns a new anonymous procedure, which when called will
invoke the static method whose name is the string <em class="replaceable"><code>method</code></em>
in the class whose name is <em class="replaceable"><code>class</code></em>.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869284928" class="indexterm"/> <code class="function">primitive-interface-method</code> <em class="replaceable"><code>interface</code></em> <em class="replaceable"><code>method</code></em> <em class="replaceable"><code>rtype</code></em> (<em class="replaceable"><code>argtype</code></em> <em class="replaceable"><code>...</code></em>)</p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Returns a new anonymous procedure, which when called will
invoke the matching method from the interface whose name is <em class="replaceable"><code>interface</code></em>.
</p>
          </blockquote>
        </div>
        <p>The macros return procedure values, just like <code class="literal">lambda</code>.
If the macros are used directly as the procedure of a procedure call,
then kawa can inline the correct bytecodes to call the specified methods.
(Note also that neither macro
checks that there really is a method that matches the specification.)
Otherwise, the Java reflection facility is used.
</p>
      </section>
      <section class="sect2" title="Low-level field operations" epub:type="division" id="idm139667869278080">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title">Low-level field operations</h3>
            </div>
          </div>
        </div>
        <p>The following macros evaluate to procedures that can be used to
access or change the fields of objects or static fields.
The compiler can inline each to a single bytecode instruction
(not counting type conversion).
</p>
        <p>These macros are deprecated.
The <code class="literal">fields</code> and <code class="literal">static-field</code> functions
(see <a class="link" href="Field-operations.xhtml" title="Accessing object fields">Field operations</a>) are easier to use, more powerful, and
just as efficient.  However, the high-level functions currently do
not provide access to non-public fields.
</p>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869274208" class="indexterm"/> <code class="function">primitive-get-field</code> <em class="replaceable"><code>class</code></em> <em class="replaceable"><code>fname</code></em> <em class="replaceable"><code>ftype</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Use this to access a field named <em class="replaceable"><code>fname</code></em> having type <em class="replaceable"><code>type</code></em> in
class <em class="replaceable"><code>class</code></em>.  Evaluates to a new one-argument procedure,
whose argument is a reference to an object of the specified <em class="replaceable"><code>class</code></em>.
Calling that procedure returns the value of the specified field.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869268048" class="indexterm"/> <code class="function">primitive-set-field</code> <em class="replaceable"><code>class</code></em> <em class="replaceable"><code>fname</code></em> <em class="replaceable"><code>ftype</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Use this to change a field named <em class="replaceable"><code>fname</code></em> having type <em class="replaceable"><code>type</code></em> in
class <em class="replaceable"><code>class</code></em>.  Evaluates to a new two-argument procedure,
whose first argument is a reference to an object of the
specified <em class="replaceable"><code>class</code></em>, and the second argument is the new value.
Calling that procedure sets the field to the specified value.
(This macro’s name does not end in a ‘<code class="literal">!</code>’, because it does not actually
set the field.  Rather, it returns a function for setting the field.)
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869261104" class="indexterm"/> <code class="function">primitive-get-static</code> <em class="replaceable"><code>class</code></em> <em class="replaceable"><code>fname</code></em> <em class="replaceable"><code>ftype</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Like <code class="literal">primitive-get-field</code>, but used to access static fields.
Returns a zero-argument function, which when called returns
the value of the static field.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869256336" class="indexterm"/> <code class="function">primitive-set-static</code> <em class="replaceable"><code>class</code></em> <em class="replaceable"><code>fname</code></em> <em class="replaceable"><code>ftype</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Like <code class="literal">primitive-set-field</code>, but used to modify static fields.
Returns a one-argument function, which when called sets the
value of the static field to the argument.
</p>
          </blockquote>
        </div>
        <span id="Low-level-array-macros"/>
      </section>
      <section class="sect2" title="Old low-level array macros" epub:type="division" id="idm139667869251152">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title">Old low-level array macros</h3>
            </div>
          </div>
        </div>
        <p>The following macros evaluate to procedures that can be used to
manipulate primitive Java array objects.
The compiler can inline each to a single bytecode instruction
(not counting type conversion).
</p>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869249472" class="indexterm"/> <code class="function">primitive-array-new</code> <em class="replaceable"><code>element-type</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Evaluates to a one-argument procedure.  Applying the resulting procedure to
an integer count allocates a new Java array of the specified length,
and whose elements have type <em class="replaceable"><code>element-type</code></em>.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869245520" class="indexterm"/> <code class="function">primitive-array-set</code> <em class="replaceable"><code>element-type</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Evaluates to a three-argument procedure.  The first argument of
the resulting procedure must be an array whose elements have type
<em class="replaceable"><code>element-type</code></em>;  the second argument is an index;  and the third
argument is a value (coercible to <em class="replaceable"><code>element-type</code></em>) which replaces
the value specified by the index in the given array.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869241024" class="indexterm"/> <code class="function">primitive-array-get</code> <em class="replaceable"><code>element-type</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Evaluates to a two-argument procedure.  The first argument of
the resulting procedure must be an array whose elements have type
<em class="replaceable"><code>element-type</code></em>;  the second argument is an index.
Applying the procedure returns the element at the specified index.
</p>
          </blockquote>
        </div>
        <p class="synopsis" kind="Syntax"><span class="kind">Syntax</span><span class="ignore">: </span><a id="idm139667869237008" class="indexterm"/> <code class="function">primitive-array-length</code> <em class="replaceable"><code>element-type</code></em></p>
        <div class="blockquote">
          <blockquote class="blockquote">
            <p>Evaluates to a one-argument procedure.  The argument of
the resulting procedure must be an array whose elements have type
<em class="replaceable"><code>element-type</code></em>.
Applying the procedure returns the length of the array.
(Alternatively, you can use <code class="literal">(field <em class="replaceable"><code>array</code></em> 'length)</code>.)
</p>
          </blockquote>
        </div>
      </section>
    </section>
    <footer>
      <div class="navfooter">
        <ul>
          <li>
            <b class="toc">
              <a href="Low-level-functions.xhtml#idm139667869304896">Low-level Method invocation</a>
            </b>
          </li>
          <li>
            <b class="toc">
              <a href="Low-level-functions.xhtml#idm139667869278080">Low-level field operations</a>
            </b>
          </li>
          <li>
            <b class="toc">
              <a href="Low-level-functions.xhtml#idm139667869251152">Old low-level array macros</a>
            </b>
          </li>
        </ul>
        <p>
          Up: <a accesskey="u" href="Miscellaneous.xhtml">Miscellaneous topics</a></p>
        <p>
        Previous: <a accesskey="p" href="Time-related-functions.xhtml">Time-related functions</a></p>
      </div>
    </footer>
  </body>
</html>