Editing Preprocessor (section)

{{short description|Program that processes input for another program}}
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{{Data transformation}}

In [[computer science]], a '''preprocessor''' (or '''precompiler''')<ref>{{cite web
   |url=https://www.ibm.com/docs/zosbasics/com.ibm.zos.zappldev/zappldev_111.htm
   |title=What is a precompiler?|website=[[IBM]] }}</ref> is a [[Computer program|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 [[compiler]]s. 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 (computer science)|macro]] expansions, while others have the power of full-fledged [[programming language]]s.

A common example from [[computer programming]] is the processing performed on [[source code]] before the next step of compilation.
In some [[computer language]]s (e.g., [[C (programming language)|C]] and [[PL/I (programming language)|PL/I]]) there is a phase of [[compiler|translation]] known as ''preprocessing''. It can also include macro processing, file inclusion and language extensions.