Compact set of positions
type t
A t
value represent a sequence of positions. The focus is on small memory footprint.
Given a s-expression and a sequence of positions, one can reconstruct the location of every sub s-expression. This is used to report location informations without having to annotate every node in the s-expression during parsing.
The s-expression parser saves the positions of each opening and closing parentheses as well as the positions of the first and last character of each atom.
Note that a t
can hold the same given positions no more than twice. The parser
stores the same position twice for non-quoted single character atoms.
type pos
=
{
line : Base.int; | (** Line number. The first line has number |
col : Base.int; | (** Column number. The first column has number |
offset : Base.int; | (** Number of bytes from the beginning of the input. The first
byte has offset |
}
Represent a position in the input
val beginning_of_file : pos
Range of positions, as reported in error messages. We follow the lexing conventions of
OCaml, i.e. start_pos
points to the first character and end_pos
points to the
position just after the last character.
This allow for instance to represent empty ranges with start_pos = end_pos
.
include sig ... end
val sexp_of_range : range ‑> Sexplib.Sexp.t
Make a range from two positions where both positions are inclusive, i.e. start_pos
points to the first character and end_pos
points to the last one.
The character at last_pos
is assumed to not be a newline character.
find t start stop
returns the range of positions starting at position with index
start
in t
and ending at position with index stop
.
find t i j
is the same as:
let a = to_array t in
make_range_incl ~start_pos:a.(i) ~last_pos:a.(j)
but more efficient.
val find_sub_sexp_phys : t ‑> Base.Sexp.t ‑> sub:Base.Sexp.t ‑> range Base.option
find_sub_sexp_phys t sexp ~sub
looks for sub
in sexp
and return its location,
assuming t
is the sequence of positions associated with sexp
.
Comparison is done using physical equality.
val find_sub_sexp_in_list_phys : t ‑> Base.Sexp.t Base.list ‑> sub:Base.Sexp.t ‑> range Base.option