Genlex(3o)							   OCaml library							Genlex(3o)

NAME

       Genlex - A generic lexical analyzer.

Module
       Module	Genlex

Documentation
       Module Genlex
	: sig end

       A generic lexical analyzer.

       This  module  implements a simple ``standard'' lexical analyzer, presented as a function from character streams to token streams. It imple-
       ments roughly the lexical conventions of Caml, but is parameterized by the set of keywords of your language.

       Example: a lexer suitable for a desk calculator is obtained by let lexer = make_lexer ["+";"-";"*";"/";"let";"="; ( ; ) ]

       The associated parser would be a function from token stream to, for instance, int , and would have rules such as:

       let parse_expr = parser [< 'Int n >] -> n | [< 'Kwd ( ; n = parse_expr; 'Kwd ) >] -> n | [< n1 = parse_expr; n2 = parse_remainder n1 >]	->
       n2 and parse_remainder n1 = parser [< 'Kwd + ; n2 = parse_expr >] -> n1+n2 | ...

       type token =
	| Kwd of string
	| Ident of string
	| Int of int
	| Float of float
	| String of string
	| Char of char

       The  type of tokens. The lexical classes are: Int and Float for integer and floating-point numbers; String for string literals, enclosed in
       double quotes; Char for character literals, enclosed in single quotes; Ident for identifiers (either sequences of letters,  digits,  under-
       scores  and quotes, or sequences of ``operator characters'' such as + , * , etc); and Kwd for keywords (either identifiers or single ``spe-
       cial characters'' such as ( , } , etc).

       val make_lexer : string list -> char Stream.t -> token Stream.t

       Construct the lexer function. The first argument is the list of keywords. An identifier s is returned as Kwd s if s belongs to  this  list,
       and  as	Ident  s  otherwise.   A  special character s is returned as Kwd s if s belongs to this list, and cause a lexical error (exception
       Parse_error ) otherwise. Blanks and newlines are skipped.  Comments delimited by (* and *) are skipped as well, and can be nested.

OCamldoc							    2012-06-26								Genlex(3o)