Syntax directed mappings of context Free languages

A definition of meaning is given for languages that possess a parsing algorithm. This definition leads to consider a class of mappings called syntax directed mappings. The behavior of contextfree languages is studied in relation to the defined class of mappings and it is shown that the translation can be implemented in two passes: first by a nondeterministic push down automaton and then by a two-way deterministic push down automaton. Nondeterministic sequential machines are also studied as a particular elementary case of syntax directed mappings.