(Or "linear analysis", "scanning") The fiRSt stage of processing a language. The stream of characteRS making up the source program or other input is read one at a time and grouped into lexemes (or "tokens") - word-like pieces such as keywords, identifieRS, literals and punctutation. The lexemes are then passed to the paRSer. ["CompileRS - Principles, Techniques and Tools", by Alfred V. Aho, Ravi Sethi and Jeffrey D. Ullman, pp. 4-5] (1995-04-05)