1
2
3
4
5
6
|
<html><head><title>let</title><h1>let</h1></head><body><ul><li><code class="scheme">(<code class="scheme"><span class="keyword">let</span></code> ((<b>NAME</b> <b>EXPRESSION</b>) ...) <b>EXPRESSION</b>) </code><br /> The <code class="scheme"><span class="keyword">let</span></code> expression is similar to the <code class="scheme"><span class="keyword">letrec</span></code> expression, except that the scope of the bindings is different. Like <code class="scheme"><span class="keyword">letrec</span></code>, the body expression may refer to the bindings created by the <code class="scheme"><span class="keyword">let</span></code>. However, the binding expressions (those on the right-hand sides) may not refer to these bindings. To illustrate this, consider the following expressions and its result: <pre>(define a 3)
(let ((a 16)
(b a))
(+ b a))
19
</pre> In other words, <code class="scheme"><span class="variable">b</span></code>'s reference to <code class="scheme"><span class="variable">a</span></code> is bound to the top-level <code class="scheme"><span class="variable">a</span></code>, rather than the inner one. </li><li><code class="scheme"> (<code class="scheme"><span class="keyword">let</span></code> <b>NAME</b> ((<b>NAME</b> <b>EXPRESSION</b>) ...) <b>EXPRESSION</b>) </code><br /> This is the same as the <a href="recur.html"><code class="scheme"><span class="keyword">recur</span></code></a> expression. </li></ul><p><a href="index.htm">Advanced Student Language</a></p></body></html>
|
