Program that processes input for another program

<span class="mw-page-title-main">Preprocessor</span>

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Preprocessor

<p>In <a href="/en/Computer_science" title="Computer science" class="wl">computer science</a>, a <b>preprocessor</b> (or <b>precompiler</b>)<span class="mw-ref reference" id="cite_ref-1"><a href="#cite_note-1" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text">[1]</span></a></span> is a <a href="/en/Computer_program" title="Computer program" class="wl">program</a> that processes its input data to produce output that is used as input in another program. The output is said to be a <b>preprocessed</b> form of the input data, which is often used by some subsequent programs like <a href="/en/Compiler" title="Compiler" class="wl">compilers</a>. The amount and kind of processing done depends on the nature of the preprocessor; some preprocessors are only capable of performing relatively simple textual substitutions and <a href="/en/Macro_(computer_science)" title="Macro (computer science)" class="wl">macro</a> expansions, while others have the power of full-fledged <a href="/en/Programming_language" title="Programming language" class="wl">programming languages</a>.</p>

<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none" about="#mwt1">Program that processes input for another program</div>
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padding:2px">
Concepts</th></tr><tr><td class="sidebar-content hlist">
<ul><li><a href="/en/Metadata" title="Metadata" class="wl">Metadata</a></li>
<li><a href="/en/Data_element" title="Data element" class="wl">Data element</a></li>
<li><a href="/en/Data_mapping" title="Data mapping" class="wl">Data mapping</a></li>
<li><a href="/en/Data_migration" title="Data migration" class="wl">Data migration</a></li>
<li><a href="/en/Data_transformation_(computing)" title="Data transformation (computing)" class="wl">Data transformation</a></li>
<li><a href="/en/Model_transformation" title="Model transformation" class="wl">Model transformation</a></li>
<li><a href="/en/Macro_(computer_science)" title="Macro (computer science)" class="wl">Macro</a></li>
<li><a href="/en/Preprocessor" title="Preprocessor" class="wl">Preprocessor</a></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background:#E7C6A5; padding:2px">
<a href="/en/Transformation_language" title="Transformation language" class="wl">Transformation languages</a></th></tr><tr><td class="sidebar-content hlist">
<ul><li><a href="/en/ATLAS_Transformation_Language" title="ATLAS Transformation Language" class="wl">ATL</a></li>
<li><a href="/en/AWK" title="AWK" class="wl">AWK</a></li>
<li><a href="/en/MOFM2T" title="MOFM2T" class="mw-redirect wl">MOFM2T</a></li>
<li><a href="/en/QVT" title="QVT" class="wl">QVT</a></li>
<li><a href="/en/XML_transformation_language" title="XML transformation language" class="wl">XML languages</a></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background:#E7C6A5; padding:2px">
Techniques and transforms</th></tr><tr><td class="sidebar-content hlist">
<ul><li><a href="/en/Identity_transform" title="Identity transform" class="wl">Identity transform</a></li>
<li><a href="/en/Data_refinement" title="Data refinement" class="mw-redirect wl">Data refinement</a></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background:#E7C6A5; padding:2px">
Applications</th></tr><tr><td class="sidebar-content hlist">
<ul><li><a href="/en/Data_conversion" title="Data conversion" class="wl">Data conversion</a></li>
<li><a href="/en/Data_migration" title="Data migration" class="wl">Data migration</a></li>
<li><a href="/en/Data_integration" title="Data integration" class="wl">Data integration</a></li>
<li><a href="/en/Extract,_transform,_load" title="Extract, transform, load" class="wl">Extract, transform, load</a> (ETL)</li>
<li><a href="/en/Web_template_system" title="Web template system" class="wl">Web template system</a></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background:#E7C6A5; padding:2px">
Related</th></tr><tr><td class="sidebar-content hlist">
<ul><li><a href="/en/Data_wrangling" title="Data wrangling" class="wl">Data wrangling</a></li>
<li><a href="/en/Transformation_language" title="Transformation language" class="wl">Transformation languages</a></li></ul></td>
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<p>A common example from <a href="/en/Computer_programming" title="Computer programming" class="wl">computer programming</a> is the processing performed on <a href="/en/Source_code" title="Source code" class="wl">source code</a> before the next step of compilation.
In some <a href="/en/Computer_language" title="Computer language" class="wl">computer languages</a> (e.g., <a href="/en/C_(programming_language)" title="C (programming language)" class="wl">C</a> and <a href="/en/PL/I_(programming_language)" title="PL/I (programming language)" class="mw-redirect wl">PL/I</a>) there is a phase of <a href="/en/Compiler" title="Compiler" class="wl">translation</a> known as <i>preprocessing</i>. It can also include macro processing, file inclusion and language extensions.</p>



In computer science, a preprocessor  is a program that processes its input data to produce output that is used as input in another program. The output is said to be a preprocessed form of the input data, which is often used by some subsequent programs like compilers. The amount and kind of processing done depends on the nature of the preprocessor; some preprocessors are only capable of performing relatively simple textual substitutions and macro expansions, while others have the power of full-fledged programming languages. A common example from computer programming is the processing performed on source code before the next step of compilation.
In some computer languages there is a phase of translation known as preprocessing. It can also include macro processing, file inclusion and language extensions. 