Source-to-source compiler: Difference between revisions

Revision as of 18:42, 23 April 2025

Revision as of 21:54, 7 May 2025

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A '''source-to-source translator''', '''source-to-source compiler''' ('''S2S compiler'''), '''transcompiler''', or '''transpiler'''<ref name="ARC_1988_Transpiler"/><ref name="Pountain_1989"/><ref name="Sector7_1993_Transpiler"/> is a type of [[translatorTranslator (computing)|translator]] that takes the [[source code]] of a program written in a [[programming language]] as its input and produces an equivalent source code in the same or a different programming language, usually as an [[intermediate representation]]. A source-to-source translator converts between programming languages that operate at approximately the same level of [[abstractionAbstraction (computer science)|abstraction]], while a traditional [[compiler]] translates from a [[highHigh-level programming language|higher level programming language]] to a [[lowLow-level programming language|lower level programming language]]. For example, a source-to-source translator may perform a translation of a program from [[Python (programming language)|Python]] to [[JavaScript (programming language)|JavaScript]], while a traditional compiler translates from a language like [[C (programming language)|C]] to [[Assembly language|assembly]] or [[Java (programming language)|Java]] to [[Java bytecode|bytecode]].<ref name="Devopedia_Transpiler"/> An [[automatic parallelizing]] compiler will frequently take in a high level language program as an input and then transform the code and annotate it with parallel code annotations (e.g., [[OpenMP]]) or language constructs (e.g. [[Fortran]]'s <code>forall</code> statements).<ref name="Pountain_1989"/><ref name="Compiler_Types"/>

Another purpose of source-to-source-compiling is translating legacy code to use the next version of the underlying programming language or an application programming interface ([[API]]) that breaks backward compatibility. It will perform automatic [[code refactoring]] which is useful when the programs to refactor are outside the control of the original implementer (for example, converting programs from Python 2 to Python 3, or converting programs from an old API to the new API) or when the size of the program makes it impractical or time-consuming to refactor it by hand.

Transcompilers may either keep translated code structure as close to the source code as possible to ease development and [[debugging]] of the original source code or may change the structure of the original code so much that the translated code does not look like the source code.<ref name="Fowler_2013"/> There are also debugging utilities that map the transcompiled source code back to the original code; for example, the [[JavaScript]] Source Map standard{{Citation needed|reason=Not a standard|date=September 2020}} allows mapping of the JavaScript code executed by a [[web browser]] back to the original source when the JavaScript code was, for example, minified or produced by a transcompiled-to-JavaScript language.{{Citation needed|date=September 2020}}