| Parsing is almost always a part of a programming language compiler but it doesn't have to be. When we parse a string, we go up from low-level human-readable strings to intermediate parse trees to a high-level AST. A process of compilation goes down from some kind of a high-level internal representation through phases to something that is close to the target low-level language. It can go down from an AST, or LLVM-s internal representation, or whatever. Problems solved by both processes are different: 1. Parsing is about finding string patterns (using regexps or PEGs or whatever) and representing these using a more strict high-level structure. The structure is usually tree-like but is also often a graph. 2. Compiling takes something high-level (a tree, a graph, etc) and emits something different, usually simplified. A good example is a typical lisp implementation where the parser is trivial but compilation phases represent numerous simplifying phases. |