The structures of his input, together with code to be Yacc provides a general tool for describing the Limited, difficult to use, and often are lax about Unfortunately, usual input facilities are An input language may be as complexĪs a programming language, or as simple as a sequence In fact, every computer program that does inputĬan be thought of as defining an ``input language'' JohnsonĬomputer program input generally has some structure Yacc: Yet Another Compiler-Compiler Stephen C. Order in which the corresponding regular expressions occur in the The program fragments written by the user are executed in the Performed by a deterministic finite automaton generated by Lex. Partitioning the input into strings which match the given expressions.Īs each such string is recognized the corresponding program fragment Which reads an input stream, copying it to an output stream and Lex source is a table of regular expressions and corresponding Input in preparation for a parsing routine. Suited for editor-script type transformations and for segmenting Instances of regular expressions in the input stream. Lex helps write programs whose control flow is directed by Split the source file into tokens ( Lex).įind the hierarchical structure of the program ( Yacc). The task of discovering the source structure again is decomposed into

to generate the target program.Ĭan generate program fragments that solve the first task. Read the source program and discover its structure. The asteroid to kill this dinosaur is still in orbit.Ī compiler or interptreter for a programminning language

Lex compiler editor online