Preprocessor

In <a href="/facts/Computer_science/lN3pEyPz">computer science</a>, a preprocessor (or precompiler) is a <a href="/facts/Computer_program/e38jH9N9">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 preprocessed form of the input data, which is often used by some subsequent programs like <a href="/facts/Compiler/WNfCDFJe">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="/facts/Macro_(computer_science)/7abAsm1o">macro</a> expansions, while others have the power of full-fledged <a href="/facts/Programming_language/cWTYbgWa">programming languages</a>.
A common example from <a href="/facts/Computer_programming/QmSsFnu0">computer programming</a> is the processing performed on <a href="/facts/Source_code/o9J6Jv23">source code</a> before the next step of compilation.
In some <a href="/facts/Computer_language/n3L56qdP">computer languages</a> (e.g., <a href="/facts/C_(programming_language)/Ky2No763">C</a> and <a href="/facts/PL%2fI_(programming_language)/469mVYgd">PL/I</a>) there is a phase of <a href="/facts/Compiler/WNfCDFJe">translation</a> known as preprocessing. It can also include macro processing, file inclusion and language extensions.

Preprocessor open-in-new

Preprocessor