module Lexing:sig
..end
ocamllex
.type
position = {
|
pos_fname : |
|
pos_lnum : |
|
pos_bol : |
|
pos_cnum : |
position
describes a point in a source file.
pos_fname
is the file name; pos_lnum
is the line number;
pos_bol
is the offset of the beginning of the line (number
of characters between the beginning of the lexbuf and the beginning
of the line); pos_cnum
is the offset of the position (number of
characters between the beginning of the lexbuf and the position).
The difference between pos_cnum
and pos_bol
is the character
offset within the line (i.e. the column number, assuming each
character is one column wide).
See the documentation of type lexbuf
for information about
how the lexing engine will manage positions.
val dummy_pos : position
position
, guaranteed to be different from any
valid position.type
lexbuf = {
|
refill_buff : |
|
mutable lex_buffer : |
|
mutable lex_buffer_len : |
|
mutable lex_abs_pos : |
|
mutable lex_start_pos : |
|
mutable lex_curr_pos : |
|
mutable lex_last_pos : |
|
mutable lex_last_action : |
|
mutable lex_eof_reached : |
|
mutable lex_mem : |
|
mutable lex_start_p : |
|
mutable lex_curr_p : |
At each token, the lexing engine will copy lex_curr_p
to
lex_start_p
, then change the pos_cnum
field
of lex_curr_p
by updating it with the number of characters read
since the start of the lexbuf
. The other fields are left
unchanged by the lexing engine. In order to keep them
accurate, they must be initialised before the first use of the
lexbuf, and updated by the relevant lexer actions (i.e. at each
end of line -- see also new_line
).
val from_channel : in_channel -> lexbuf
Lexing.from_channel inchan
returns a lexer buffer which reads
from the input channel inchan
, at the current reading position.val from_string : string -> lexbuf
val from_function : (bytes -> int -> int) -> lexbuf
s
and a byte
count n
. The function should put n
bytes or fewer in s
,
starting at index 0, and return the number of bytes
provided. A return value of 0 means end of input.lexbuf
, which, in the code generated by
ocamllex
, is bound to the lexer buffer passed to the parsing
function.val lexeme : lexbuf -> string
Lexing.lexeme lexbuf
returns the string matched by
the regular expression.val lexeme_char : lexbuf -> int -> char
Lexing.lexeme_char lexbuf i
returns character number i
in
the matched string.val lexeme_start : lexbuf -> int
Lexing.lexeme_start lexbuf
returns the offset in the
input stream of the first character of the matched string.
The first character of the stream has offset 0.val lexeme_end : lexbuf -> int
Lexing.lexeme_end lexbuf
returns the offset in the input stream
of the character following the last character of the matched
string. The first character of the stream has offset 0.val lexeme_start_p : lexbuf -> position
lexeme_start
, but return a complete position
instead
of an offset.val lexeme_end_p : lexbuf -> position
lexeme_end
, but return a complete position
instead
of an offset.val new_line : lexbuf -> unit
lex_curr_p
field of the lexbuf to reflect the start
of a new line. You can call this function in the semantic action
of the rule that matches the end-of-line character.val flush_input : lexbuf -> unit