Module B0_sexp.Sexp

S-expression definitions and codec.

Meta information

type 'a fmt = Stdlib.Format.formatter -> 'a -> unit

The type for formatting functions.

type loc = B0_text.Tloc.t

The type for source text locations.

val loc_nil : B0_text.Tloc.t

loc_nil is a source text location for non-parsed s-expressions.

val pp_loc : loc fmt

pp_loc is Tloc.pp.

type a_meta

The type for meta information about atoms.

type l_meta

The type for meta information about lists.

val a_meta_nil : a_meta

a_meta_nil is parse information for non-parsed atoms.

val l_meta_nil : l_meta

l_meta_nil is parse information for non-parsed lists.

S-expressions

type t = [
  1. | `A of string * a_meta
  2. | `L of t list * l_meta
]

The type for generic s-expression representations. Either an atom or a list.

val atom : string -> t

atom a is `A (a, a_meta_nil).

val list : t list -> t

list l is `L (l, l_meta_nil).

Accessors

val loc : t -> loc

loc s is s's source text location.

val to_atom : t -> (string, string) Stdlib.result

to_atom s extracts an atom from s. If s is a list an error with the location formatted according to Tloc.pp is returned.

val get_atom : t -> string

get_atom s is like to_atom but raises Invalid_argument if s is not an atom.

val to_list : t -> (t list, string) Stdlib.result

to_list s extracts a list from s. If s is an atom an error with the location formatted according to Tloc.pp is returned.

val get_list : t -> t list

get_atom s is like to_list but raises Invalid_argument if s is not an list.

val to_splice : t -> t list

to_splice s is the either the list of s if s is or or [s] if s is an atom.

Formatting

val pp : t fmt

pp formats an s-expression.

val pp_layout : t fmt

pp_layout ppf l is like pp but uses layout information.

val pp_seq : t fmt

pp_seq formats an s-expression but if it is a list the outer list separators are not formatted in the output.

Warning. Assumes all OCaml strings in the formatted value are UTF-8 encoded.

val pp_seq_layout : t fmt

pp_seq_layout is like pp_seq but uses layout information.

Codec

type error_kind

The type for kinds of decoding error.

val pp_error_kind : unit -> error_kind fmt

pp_error_kind () formats an error kind.

type error = error_kind * loc

The type for decoding errors.

val pp_error : ?pp_loc:loc fmt -> ?pp_error_kind:error_kind fmt -> ?pp_prefix:unit fmt -> unit -> error fmt

pp_error ~pp_loc ~pp_error_kind ~pp_prefix () formats errors using pp_loc (defaults to pp_loc), pp_error_kind (defaults to pp_error_kind) and pp_prefix (defaults formats "Error: ").

val error_to_string : ?pp_error:error fmt -> ('a, error) Stdlib.result -> ('a, string) Stdlib.result

error_to_string r converts an error to a string using pp_error (defaults to pp_error).

val seq_of_string : ?file:B0_text.Tloc.fpath -> string -> (t, error) Stdlib.result

seq_of_string ?file s parses a sequence of s-expressions from s. file is the file for locations, defaults to "-". The sequence is returned as a fake s-expression list that spans from the start of the first s-expression in s to the end of the last one; note that this list does not exist syntactically in s.

If there are no s-expression in s the list is empty its location has both start and end positions at byte 0 (which may not exist).

Note. All OCaml strings returned by this function are UTF-8 encoded.

val seq_of_string' : ?pp_error:error fmt -> ?file:B0_text.Tloc.fpath -> string -> (t, string) Stdlib.result

seq_of_string' s seq_of_string composed with error_to_string.

val seq_to_string : t -> string

seq_to_string s encodes s to a sequence of s-expressions. If s is an s-expression list this wrapping list is not syntactically represented in the output (see also seq_of_string), use to_string (list [l]) if you want to output l as a list.

Warning. Assumes all OCaml strings in s are UTF-8 encoded.

S-expression indices

type index =
  1. | Nth of int
  2. | Key of string

The type for s-expression indexing operations.

  • Nth n, lookup zero-based element n in a list. If n is negative, counts the number of elements from the end of the list, i.e. -1 is the last list element.
  • Key k, lookup binding k in an s-expression dictionary.
val pp_key : string fmt

pp_key formats a key, this is Format.pp_print_string.

val pp_index : ?pp_key:string fmt -> unit -> index fmt

pp_index formats indices. Keys are unbracketed and formatted with pp_key, defaults to pp_key.

S-expression paths

type path = index list

The type for paths, a sequence of indexing operations in reverse order.

val path_of_string : string -> (path, string) Stdlib.result

path_of_string parses a path from s according to the syntax given here.

val pp_path : ?pp_key:string fmt -> unit -> path fmt

pp_path ?pp_key () is a formatter for paths using pp_key to format keys (defaults to pp_key).

Carets

type caret_loc =
  1. | Before
    (*

    The void before the s-expression found by the path.

    *)
  2. | Over
    (*

    The s-expression found by the path.

    *)
  3. | After
    (*

    The void after the s-expression found by the path.

    *)

The type for caret locations.

type caret = caret_loc * path

The type for carets. A caret location and the path at which it applies.

val caret_of_string : string -> (caret, string) Stdlib.result

caret_of_string s parses a caret from s according to the syntax given here.

val pp_caret : ?pp_key:string fmt -> unit -> caret fmt

pp_caret ?pp_key () is a formatter for carets using pp_key to format keys (defaults to pp_key).