109 lines
5.0 KiB
OCaml
109 lines
5.0 KiB
OCaml
(* camlp4r *)
|
|
(***********************************************************************)
|
|
(* *)
|
|
(* Camlp4 *)
|
|
(* *)
|
|
(* Daniel de Rauglaudre, projet Cristal, INRIA Rocquencourt *)
|
|
(* *)
|
|
(* Copyright 2001 Institut National de Recherche en Informatique et *)
|
|
(* Automatique. Distributed only by permission. *)
|
|
(* *)
|
|
(***********************************************************************)
|
|
|
|
(* This file has been generated by program: do not edit! *)
|
|
|
|
(* Module [Token]: lexers for Camlp4 grammars *)
|
|
|
|
(* This module defines the Camlp4 lexer type to be used in extensible
|
|
grammars (see module [Grammar]). It also provides some useful functions
|
|
to create lexers (this module should be renamed [Glexer] one day). *)
|
|
|
|
(*** Token type *)
|
|
|
|
type t = string * string;;
|
|
type pattern = string * string;;
|
|
(* Token and token patterns. Token are build by the lexer. Token
|
|
patterns come from the EXTEND statement.
|
|
- The first string is the constructor name (must start with
|
|
an uppercase character). When it is empty, the second string
|
|
is supposed to be a keyword.
|
|
- The second string is the constructor parameter. Empty if it
|
|
has no parameter.
|
|
- The way tokens pattern are interpreted to parse tokens is
|
|
done by the lexer, function [tparse] below. *)
|
|
|
|
exception Error of string;;
|
|
(* An lexing error exception to be used by lexers. *)
|
|
|
|
(*** Lexer type *)
|
|
|
|
type location = int * int;;
|
|
type location_function = int -> location;;
|
|
(* The type for a function associating a number of a token in a stream
|
|
(starting from 0) to its source location. *)
|
|
type lexer_func = char Stream.t -> t Stream.t * location_function;;
|
|
(* The type for a lexer function. The character stream is the input
|
|
stream to be lexed. The result is a pair of a token stream and
|
|
a location function for this tokens stream. *)
|
|
|
|
type lexer =
|
|
{ func : lexer_func;
|
|
using : pattern -> unit;
|
|
removing : pattern -> unit;
|
|
tparse : pattern -> (t Stream.t -> string) option;
|
|
text : pattern -> string }
|
|
;;
|
|
(* The type for a lexer used by Camlp4 grammars.
|
|
- The field [func] is the main lexer function. See [lexer_func]
|
|
type above. This function may be created from a [char stream parser]
|
|
or for an [ocamllex] function using the functions below.
|
|
- The field [using] is a function telling the lexer that the grammar
|
|
uses this token (pattern). The lexer can check that its constructor
|
|
is correct, and interpret some kind of tokens as keywords (to record
|
|
them in its tables). Called by [EXTEND] statements.
|
|
- The field [removing] is a function telling the lexer that the grammar
|
|
does not uses the given token (pattern) any more. If the lexer has a
|
|
notion of "keywords", it can release it from its tables. Called by
|
|
[DELETE_RULE] statements.
|
|
- The field [tparse] is a function returning either [Some f], f being
|
|
the parsing function associated with the pattern, or [None] if it
|
|
is a standard parsing of the pattern.
|
|
- The field [text] returns the name of some token pattern,
|
|
used in error messages. *)
|
|
|
|
val lexer_text : pattern -> string;;
|
|
(* A simple [text] function for lexers *)
|
|
|
|
(*** Lexer from char stream parsers or ocamllex function *)
|
|
|
|
(* The functions below create lexer functions either from a [char stream]
|
|
parser or for an [ocamllex] function. With the returned function [f],
|
|
the simplest [Token.lexer] can be written:
|
|
- [ { Token.func = f; ]
|
|
- [ Token.using = (fun _ -> ()); ]
|
|
- [ Token.removing = (fun _ -> ()); ]
|
|
- [ Token.tparse = (fun _ -> None); ]
|
|
- [ Token.text = Token.lexer_text } ]
|
|
Note that a better [using] function should check the used tokens
|
|
and raise [Token.Error] for incorrect ones. The other functions
|
|
[removing], [tparse] and [text] may have other implementations
|
|
as well. *)
|
|
|
|
val lexer_func_of_parser : (char Stream.t -> t * location) -> lexer_func;;
|
|
(* A lexer function from a lexer written as a char stream parser
|
|
returning the next token and its location. *)
|
|
val lexer_func_of_ocamllex : (Lexing.lexbuf -> t) -> lexer_func;;
|
|
(* A lexer function from a lexer created by [ocamllex] *)
|
|
|
|
val make_stream_and_location :
|
|
(unit -> t * location) -> t Stream.t * location_function;;
|
|
|
|
(*** Useful functions *)
|
|
|
|
val eval_char : string -> char;;
|
|
val eval_string : string -> string;;
|
|
(* Convert a char or a string token, where the backslashes have not
|
|
been interpreted into a real char or string; raise [Failure] if
|
|
bad backslash sequence found; [Token.eval_char (Char.escaped c)]
|
|
returns [c] and [Token.eval_string (String.escaped s)] returns [s] *)
|