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, underscores and quotes, or sequences of 'operator characters' such as +
, *
, etc); and Kwd
for keywords (either identifiers or single 'special characters' such as (
, }
, etc).
val make_lexer : string list -> char Stdlib.Stream.t -> token Stdlib.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 Stream.Error
with the offending lexeme as its parameter) otherwise. Blanks and newlines are skipped. Comments delimited by (*
and *)
are skipped as well, and can be nested. A Stream.Failure
exception is raised if end of stream is unexpectedly reached.