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<h3 class="section">3.4 Symbols</h3>
<p><a name="index-characters-used-in-symbols-128"></a>A <dfn>symbol</dfn> is one or more characters chosen from the set of all
letters (both upper and lower case), digits and the three characters
‘<samp><span class="samp">_.$</span></samp>’.
On most machines, you can also use <code>$</code> in symbol names; exceptions
are noted in <a href="Machine-Dependencies.html#Machine-Dependencies">Machine Dependencies</a>.
No symbol may begin with a digit. Case is significant.
There is no length limit; all characters are significant. Multibyte characters
are supported. Symbols are delimited by characters not in that set, or by the
beginning of a file (since the source program must end with a newline, the end
of a file is not a possible symbol delimiter). See <a href="Symbols.html#Symbols">Symbols</a>.
<p>Symbol names may also be enclosed in double quote <code>"</code> characters. In such
cases any characters are allowed, except for the NUL character. If a double
quote character is to be included in the symbol name it must be preceeded by a
backslash <code>\</code> character.
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