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<title>avram - a virtual machine code interpreter: 2.7.4.1 Syntax</title>

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<a name="Syntax"></a>
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<a name="Syntax-1"></a>
<h4 class="subsubsection">2.7.4.1 Syntax</h4>

<p><code>silly</code> has no reserved words, but it has equals signs, commas and
parentheses built in. A concise but ambiguous grammar for it can be given
as follows.
<a name="index-syntax"></a>
<a name="index-grammar"></a>
</p><table><tr><td>&nbsp;</td><td><pre class="display">
<var>program</var> ::= <var>declaration</var>*

<var>declaration</var> ::= <var>identifier</var> <code>=</code> <var>expression</var>

<var>expression</var> ::= () | <var>identifier</var>
                    | (<var>expression</var>)
                    | (<var>expression</var>,<var>expression</var>)
                    | <var>expression</var> <var>expression</var>
                    | <var>expression</var>(<var>expression</var>)
                    | <var>expression</var>(<var>expression</var>,<var>expression</var>)

</pre></td></tr></table>
<a name="index-precedence"></a>
<a name="index-operator-precedence"></a>
<p>The real grammar is consistent with this one but enforces right
associativity for binary operations and higher precedence for juxtaposition
without intervening white space.
</p>
<p>The declaration of any identifier must be unique and must precede its
occurrence in any expression. Hence, cyclic dependences between
declarations and &ldquo;recursive&rdquo; declarations are not allowed.
</p>
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