Transcompilers

Transcompilers, also known as source-to-source compilers or transpilers, are programs that translate source code written in one programming language into source code written in another programming language. Unlike traditional compilers that convert source code into machine code, transcompilers operate at the level of human-readable source code. This means the output of a transcompiler is still a programming language that can be read and understood by developers.

The primary purpose of transcompilation is to enable the use of newer language features or paradigms in environments that only support older languages, or to allow code written in one language to be executed on platforms that natively support another. For instance, a common use case is transpiling code written in modern JavaScript (like ES6+) into an older version of JavaScript (like ES5) to ensure compatibility with a wider range of web browsers. Another example is transpiling TypeScript, a superset of JavaScript, into plain JavaScript.

Transcompilation can also facilitate code migration between languages that share similar paradigms but have different syntax or specific functionalities. Developers might use transcompilers to convert code from Python to JavaScript, or from C++ to Rust, to leverage the strengths of different languages or to modernize existing codebases. The process typically involves parsing the source code, building an abstract syntax tree (AST), and then traversing and transforming the AST to generate the equivalent code in the target language. While transcompilation can significantly streamline development workflows and improve compatibility, the resulting code may sometimes be less optimized or harder to debug than natively written code in the target language.