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<title>7.3 Names</title>
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<h2 class="section" id="s:names"><a class="section-anchor" href="#s:names" aria-hidden="true"></a>7.3 Names</h2>
<p>Identifiers are used to give names to several classes of language
objects and refer to these objects by name later:
</p><ul class="itemize"><li class="li-itemize">
value names (syntactic class <a class="syntax" href="#value-name"><span class="c010">value-name</span></a>),
</li><li class="li-itemize">value constructors and exception constructors (class <a class="syntax" href="#constr-name"><span class="c010">constr-name</span></a>),
</li><li class="li-itemize">labels (<a class="syntax" href="lex.html#label-name"><span class="c010">label-name</span></a>, defined in section <a href="lex.html#sss%3Alabelname">7.1</a>),
</li><li class="li-itemize">polymorphic variant tags (<a class="syntax" href="#tag-name"><span class="c010">tag-name</span></a>),
</li><li class="li-itemize">type constructors (<a class="syntax" href="#typeconstr-name"><span class="c010">typeconstr-name</span></a>),
</li><li class="li-itemize">record fields (<a class="syntax" href="#field-name"><span class="c010">field-name</span></a>),
</li><li class="li-itemize">class names (<a class="syntax" href="#class-name"><span class="c010">class-name</span></a>),
</li><li class="li-itemize">method names (<a class="syntax" href="#method-name"><span class="c010">method-name</span></a>),
</li><li class="li-itemize">instance variable names (<a class="syntax" href="#inst-var-name"><span class="c010">inst-var-name</span></a>),
</li><li class="li-itemize">module names (<a class="syntax" href="#module-name"><span class="c010">module-name</span></a>),
</li><li class="li-itemize">module type names (<a class="syntax" href="#modtype-name"><span class="c010">modtype-name</span></a>).
</li></ul><p>
These eleven name spaces are distinguished both by the context and by the
capitalization of the identifier: whether the first letter of the
identifier is in lowercase (written <a class="syntax" href="lex.html#lowercase-ident"><span class="c010">lowercase-ident</span></a> below) or in
uppercase (written <a class="syntax" href="lex.html#capitalized-ident"><span class="c010">capitalized-ident</span></a>). Underscore is considered a
lowercase letter for this purpose.</p><h4 class="subsubsection" id="sss:naming-objects"><a class="section-anchor" href="#sss:naming-objects" aria-hidden="true"></a>Naming objects</h4>
<p>
<a id="hevea_manual.kwd0"></a>
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<a id="hevea_manual.kwd2"></a>
<a id="hevea_manual.kwd3"></a>
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<a id="hevea_manual.kwd6"></a></p><div class="syntax"><table class="display dcenter"><tr class="c019"><td class="dcell"><table class="c001 cellpading0"><tr><td class="c018">
<a class="syntax" id="value-name"><span class="c010">value-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#lowercase-ident"><span class="c010">lowercase-ident</span></a>
</td></tr>
<tr><td class="c018"> </td><td class="c015">∣</td><td class="c017"> <span class="c004">(</span> <a class="syntax" href="#operator-name"><span class="c010">operator-name</span></a> <span class="c004">)</span>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="operator-name"><span class="c010">operator-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#prefix-symbol"><span class="c010">prefix-symbol</span></a> ∣ <a class="syntax" href="#infix-op"><span class="c010">infix-op</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="infix-op"><span class="c010">infix-op</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#infix-symbol"><span class="c010">infix-symbol</span></a>
</td></tr>
<tr><td class="c018"> </td><td class="c015">∣</td><td class="c017"> <span class="c004">*</span> ∣ <span class="c004">+</span> ∣ <span class="c004">-</span> ∣ <span class="c004">-.</span> ∣ <span class="c004">=</span> ∣ <span class="c004">!=</span> ∣ <span class="c004"><</span> ∣ <span class="c004">></span> ∣ <span class="c004">or</span> ∣ <span class="c004">||</span>
∣ <span class="c004">&</span> ∣ <span class="c004">&&</span> ∣ <span class="c004">:=</span>
</td></tr>
<tr><td class="c018"> </td><td class="c015">∣</td><td class="c017"> <span class="c004">mod</span> ∣ <span class="c004">land</span> ∣ <span class="c004">lor</span> ∣ <span class="c004">lxor</span> ∣ <span class="c004">lsl</span> ∣ <span class="c004">lsr</span> ∣ <span class="c004">asr</span>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="constr-name"><span class="c010">constr-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#capitalized-ident"><span class="c010">capitalized-ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="tag-name"><span class="c010">tag-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#capitalized-ident"><span class="c010">capitalized-ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="typeconstr-name"><span class="c010">typeconstr-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#lowercase-ident"><span class="c010">lowercase-ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="field-name"><span class="c010">field-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#lowercase-ident"><span class="c010">lowercase-ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="module-name"><span class="c010">module-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#capitalized-ident"><span class="c010">capitalized-ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="modtype-name"><span class="c010">modtype-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#ident"><span class="c010">ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="class-name"><span class="c010">class-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#lowercase-ident"><span class="c010">lowercase-ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="inst-var-name"><span class="c010">inst-var-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#lowercase-ident"><span class="c010">lowercase-ident</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="method-name"><span class="c010">method-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="lex.html#lowercase-ident"><span class="c010">lowercase-ident</span></a>
</td></tr>
</table></td></tr>
</table></div><p>
See also the following language extension:
<a href="indexops.html#s%3Aindex-operators">extended indexing operators</a>.</p><p>As shown above, prefix and infix symbols as well as some keywords can
be used as value names, provided they are written between parentheses.
The capitalization rules are summarized in the table below.</p><div class="tableau">
<div class="center"><table class="c000 cellpadding1" border=1><tr><td class="c014"><span class="c013">Name space</span></td><td class="c014"><span class="c013">Case of first letter</span> </td></tr>
<tr><td class="c016">
Values</td><td class="c016">lowercase </td></tr>
<tr><td class="c016">Constructors</td><td class="c016">uppercase </td></tr>
<tr><td class="c016">Labels</td><td class="c016">lowercase </td></tr>
<tr><td class="c016">Polymorphic variant tags</td><td class="c016">uppercase </td></tr>
<tr><td class="c016">Exceptions</td><td class="c016">uppercase </td></tr>
<tr><td class="c016">Type constructors</td><td class="c016">lowercase </td></tr>
<tr><td class="c016">Record fields</td><td class="c016">lowercase </td></tr>
<tr><td class="c016">Classes</td><td class="c016">lowercase </td></tr>
<tr><td class="c016">Instance variables</td><td class="c016">lowercase </td></tr>
<tr><td class="c016">Methods</td><td class="c016">lowercase </td></tr>
<tr><td class="c016">Modules</td><td class="c016">uppercase </td></tr>
<tr><td class="c016">Module types</td><td class="c016">any </td></tr>
</table></div></div><p><span class="c009">Note on polymorphic variant tags:</span> the current implementation accepts
lowercase variant tags in addition to capitalized variant tags, but we
suggest you avoid lowercase variant tags for portability and
compatibility with future OCaml versions.</p><h4 class="subsubsection" id="sss:refer-named"><a class="section-anchor" href="#sss:refer-named" aria-hidden="true"></a>Referring to named objects</h4>
<div class="syntax"><table class="display dcenter"><tr class="c019"><td class="dcell"><table class="c001 cellpading0"><tr><td class="c018">
<a class="syntax" id="value-path"><span class="c010">value-path</span></a></td><td class="c015">::=</td><td class="c017">
[ <a class="syntax" href="#module-path"><span class="c010">module-path</span></a> <span class="c004">.</span> ] <a class="syntax" href="#value-name"><span class="c010">value-name</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="constr"><span class="c010">constr</span></a></td><td class="c015">::=</td><td class="c017">
[ <a class="syntax" href="#module-path"><span class="c010">module-path</span></a> <span class="c004">.</span> ] <a class="syntax" href="#constr-name"><span class="c010">constr-name</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="typeconstr"><span class="c010">typeconstr</span></a></td><td class="c015">::=</td><td class="c017">
[ <a class="syntax" href="#extended-module-path"><span class="c010">extended-module-path</span></a> <span class="c004">.</span> ] <a class="syntax" href="#typeconstr-name"><span class="c010">typeconstr-name</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="field"><span class="c010">field</span></a></td><td class="c015">::=</td><td class="c017">
[ <a class="syntax" href="#module-path"><span class="c010">module-path</span></a> <span class="c004">.</span> ] <a class="syntax" href="#field-name"><span class="c010">field-name</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="modtype-path"><span class="c010">modtype-path</span></a></td><td class="c015">::=</td><td class="c017">
[ <a class="syntax" href="#extended-module-path"><span class="c010">extended-module-path</span></a> <span class="c004">.</span> ] <a class="syntax" href="#modtype-name"><span class="c010">modtype-name</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="class-path"><span class="c010">class-path</span></a></td><td class="c015">::=</td><td class="c017">
[ <a class="syntax" href="#module-path"><span class="c010">module-path</span></a> <span class="c004">.</span> ] <a class="syntax" href="#class-name"><span class="c010">class-name</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="classtype-path"><span class="c010">classtype-path</span></a></td><td class="c015">::=</td><td class="c017">
[ <a class="syntax" href="#extended-module-path"><span class="c010">extended-module-path</span></a> <span class="c004">.</span> ] <a class="syntax" href="#class-name"><span class="c010">class-name</span></a>
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="module-path"><span class="c010">module-path</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="#module-name"><span class="c010">module-name</span></a> { <span class="c004">.</span> <a class="syntax" href="#module-name"><span class="c010">module-name</span></a> }
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="extended-module-path"><span class="c010">extended-module-path</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="#extended-module-name"><span class="c010">extended-module-name</span></a> { <span class="c004">.</span> <a class="syntax" href="#extended-module-name"><span class="c010">extended-module-name</span></a> }
</td></tr>
<tr><td class="c018"> </td></tr>
<tr><td class="c018">
<a class="syntax" id="extended-module-name"><span class="c010">extended-module-name</span></a></td><td class="c015">::=</td><td class="c017">
<a class="syntax" href="#module-name"><span class="c010">module-name</span></a> { <span class="c004">(</span> <a class="syntax" href="#extended-module-path"><span class="c010">extended-module-path</span></a> <span class="c004">)</span> }
</td></tr>
</table></td></tr>
</table></div><p>A named object can be referred to either by its name (following the
usual static scoping rules for names) or by an access path <span class="c010">prefix</span> <span class="c004">.</span> <span class="c010">name</span>,
where <span class="c010">prefix</span> designates a module and <span class="c010">name</span> is the name of an object
defined in that module. The first component of the path, <span class="c010">prefix</span>, is
either a simple module name or an access path <span class="c010">name</span><sub>1</sub> <span class="c004">.</span> <span class="c010">name</span><sub>2</sub> …,
in case the defining module is itself nested inside other modules.
For referring to type constructors, module types, or class types,
the <span class="c010">prefix</span> can
also contain simple functor applications (as in the syntactic class
<a class="syntax" href="#extended-module-path"><span class="c010">extended-module-path</span></a> above) in case the defining module is the
result of a functor application.</p><p>Label names, tag names, method names and instance variable names need
not be qualified: the former three are global labels, while the latter
are local to a class.
</p>
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