module Atd_ast: sig .. end
Abstract syntax tree (AST) representing ATD data
type loc = Lexing.position * Lexing.position
A location in the source code.
exception Atd_error of string
Exception raised by functions of the atd library and indicating
errors.
type annot = annot_section list
An annotation, consisting of a sequence of sections.
Atd_annot provides utilities for handling annotations.
type annot_section = string * (loc * annot_field list)
represents a single annotation within edgy brackets.
<"foo" bar baz="123"> in ATD syntax translates to:
("foo", (loc1, [ ("bar", (loc2, None));
("baz", (loc3, Some "123")) ] ))
type annot_field = string * (loc * string option)
An annotation field,
i.e. a key with an optional value within an annotation.
type full_module = module_head * module_body
Contents of an ATD file.
type module_head = loc * annot
The head of an ATD file is just a list of annotations.
type module_body = module_item list
The body of an ATD file is a list of type definitions.
Type definitions are implicitely mutually
recursive. They can be sorted based on dependencies
using
Atd_util.tsort.
type module_item = [ `Type of type_def ]
There is currently only one kind of module items,
that is single type definitions.
type type_def = loc * (string * type_param * annot) *
type_expr
A type definition.
type type_param = string list
List of type variables without the tick.
type type_expr = [ `List of loc * type_expr * annot
| `Name of loc * type_inst * annot
| `Option of loc * type_expr * annot
| `Record of loc * field list * annot
| `Shared of loc * type_expr * annot
| `Sum of loc * variant list * annot
| `Tuple of loc * cell list * annot
| `Tvar of loc * string ]
A type expression is one of the following:
`Sum: a sum type (within square brackets)
`Record: a record type (within curly braces)
`Tuple: a tuple (within parentheses)
`List: a list type written list with its parameter
e.g. int list
`Option: an option type written option with its parameter
e.g. string option
`Shared: values for which sharing must be preserved. Such
type expressions may not be parametrized. Values may only
be shared if the source location of the type expression is the same.
`Name: a type name other than list or option, including
the predefined types unit, bool, int, float, string
and abstract.
`Tvar: a type variable identifier without the tick
type type_inst = loc * string * type_expr list
A type name and its arguments
type variant = [ `Inherit of loc * type_expr
| `Variant of
loc * (string * annot) * type_expr option ]
A single variant or an
inherit statement.
`Inherit statements can be expanded into variants
using
Atd_inherit
or at loading time using the
inherit_variant option
offered by the
Atd_util functions.
type cell = loc * type_expr * annot
Tuple cell. Note that annotations placed before the type
expression are supported and represented here,
such as the third cell in
(float * float * <ocaml default="0.0"> float).
type field_kind = [ `Optional | `Required | `With_default ]
Different kinds of record fields based on the
`Required: required field, e.g. id : string
`Optional: optional field without a default value, e.g.
?name : string option. The ATD type of the field
value must be an option type.
`With_default: optional field with a default value, e.g.
~websites : string list. The default value may be implicit
or specified explicitely using annotations.
Each target language that cannot omit fields
may have to specify the default in its own syntax.
Sample ATD file:
type level = [ Beginner | Advanced | Expert ]
type user = {
id : string;
?name : string option;
(* Field may be omitted when no value is set, if permitted
by the target language. *)
~websites : string list;
(* Implicit default: empty list.
Field may be omitted if the field value is
equal to the default value and the
target language permits it. *)
~level <ocaml default="`Beginner"> : level;
(* Explicit default for `ocaml'.
For instance there is no `json' annotation because
the default for undefined `JSON' fields would be to omit them. *)
}
type field = [ `Field of
loc * (string * field_kind * annot) *
type_expr
| `Inherit of loc * type_expr ]
A single record field or an
inherit statement.
`Inherit statements can be expanded into fields using
Atd_inherit
or at loading time using the
inherit_fields option
offered by the
Atd_util functions.
val loc_of_type_expr : type_expr -> loc
Extract the source location of any type expression.
val set_type_expr_loc : loc -> type_expr -> type_expr
Replace the location of the given expression.
This is a shallow substitution. Sub-expressions are not affected.
val string_of_loc : loc -> string
Convert a location into a human-readable string
such as File "foo.atd", line 123, characters 40-45.
val error : string -> 'a
error s is a shorthand for raise (Atd_error s).
val error_at : loc -> string -> 'a
error_at loc s raises Atd_error s' where s'
is the location followed by s.
val dummy_loc : loc
Dummy value for predefined constructs that are
not associated with a useful source location.
Should not show up in error messages.
val annot_of_type_expr : type_expr -> annot
Return the annotations associated with a type expression.
Note that there can be annotations in a variety of places,
not just after type expressions.
val map_annot : (annot -> annot) -> type_expr -> type_expr
Replacement of the annotations associated with a type
expression.
This is a shallow transformation as sub-expressions are not affected.
val fold : (type_expr -> 'a -> 'a) -> type_expr -> 'a -> 'a
Iteration and accumulation over each type_expr node
within a given type_expr.
: ?ignorable:string list -> type_expr -> string list
Extract all the type names occurring in a type expression
under `Name, without duplicates.
ignorable : specifies a list of type names to exclude from the result
val is_parametrized : type_expr -> bool
Test whether a type expression contains type variables (`Tvar).