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|
open Ppxlib
(* This file contains tests to ensure that [Ast_builder.value_binding] properly
translates the given [pattern] and [expression] pair into the correct
[pattern], [expression] and [value_constraint] triple. *)
(* ------- Test Setup -------- *)
#install_printer Pp_ast.Default.structure_item;;
#install_printer Pp_ast.Default.expression;;
#install_printer Pp_ast.Default.pattern;;
let loc = Location.none
[%%ignore]
(* --------- Simple case, no translation --------- *)
let pat = [%pat? f]
let expr = [%expr fun x -> x + 1]
[%%ignore]
let vb =
let open Ast_builder.Default in
pstr_value ~loc Nonrecursive [value_binding ~pat ~expr ~loc]
[%%expect{|
val vb : structure_item =
Pstr_value
( Nonrecursive
, [ { pvb_pat = Ppat_var "f"
; pvb_expr =
Pexp_function
( [ { pparam_loc = __loc
; pparam_desc = Pparam_val ( Nolabel, None, Ppat_var "x")
}
]
, None
, Pfunction_body
(Pexp_apply
( Pexp_ident (Lident "+")
, [ ( Nolabel, Pexp_ident (Lident "x"))
; ( Nolabel
, Pexp_constant (Pconst_integer ( "1", None))
)
]
))
)
; pvb_constraint = None
; pvb_attributes = __attrs
; pvb_loc = __loc
}
]
)
|}]
(* As expected here, the [pvb_constraint] field is none, the pattern and
expression are used as is. *)
(* --------- No var Ppat_constraint to pvb_constraint --------- *)
let pat = [%pat? (x : int)]
let expr = [%expr 12]
[%%ignore]
let vb =
let open Ast_builder.Default in
pstr_value ~loc Nonrecursive [value_binding ~pat ~expr ~loc]
[%%expect{|
val vb : structure_item =
Pstr_value
( Nonrecursive
, [ { pvb_pat = Ppat_var "x"
; pvb_expr = Pexp_constant (Pconst_integer ( "12", None))
; pvb_constraint =
Some
(Pvc_constraint
{ locally_abstract_univars = []
; typ = Ptyp_constr ( Lident "int", [])
})
; pvb_attributes = __attrs
; pvb_loc = __loc
}
]
)
|}]
(* --------- poly Ppat_constraint to pvb_constraint --------- *)
let pat =
Ast_builder.Default.ppat_constraint ~loc
[%pat? f]
(Ast_builder.Default.ptyp_poly ~loc
[ Loc.make ~loc "a" ]
[%type: 'a -> unit])
let expr = [%expr fun x -> unit]
[%%ignore]
let vb =
let open Ast_builder.Default in
pstr_value ~loc Nonrecursive [value_binding ~pat ~expr ~loc]
[%%expect{|
val vb : structure_item =
Pstr_value
( Nonrecursive
, [ { pvb_pat = Ppat_var "f"
; pvb_expr =
Pexp_function
( [ { pparam_loc = __loc
; pparam_desc = Pparam_val ( Nolabel, None, Ppat_var "x")
}
]
, None
, Pfunction_body (Pexp_ident (Lident "unit"))
)
; pvb_constraint =
Some
(Pvc_constraint
{ locally_abstract_univars = []
; typ =
Ptyp_poly
( [ "a"]
, Ptyp_arrow
( Nolabel
, Ptyp_var "a"
, Ptyp_constr ( Lident "unit", [])
)
)
})
; pvb_attributes = __attrs
; pvb_loc = __loc
}
]
)
|}]
(* --------- desugared locally abstract univars to pvb_constraint --------- *)
let pat =
Ast_builder.Default.ppat_constraint ~loc
[%pat? f]
(Ast_builder.Default.ptyp_poly ~loc
[ Loc.make ~loc "a" ]
[%type: 'a -> unit])
let expr = [%expr fun (type a) -> (fun _ -> unit : a -> unit)]
[%%ignore]
let vb =
let open Ast_builder.Default in
pstr_value ~loc Nonrecursive [value_binding ~pat ~expr ~loc]
[%%expect{|
val vb : structure_item =
Pstr_value
( Nonrecursive
, [ { pvb_pat = Ppat_var "f"
; pvb_expr =
Pexp_function
( [ { pparam_loc = __loc
; pparam_desc = Pparam_val ( Nolabel, None, Ppat_any)
}
]
, None
, Pfunction_body (Pexp_ident (Lident "unit"))
)
; pvb_constraint =
Some
(Pvc_constraint
{ locally_abstract_univars = [ "a"]
; typ =
Ptyp_arrow
( Nolabel
, Ptyp_constr ( Lident "a", [])
, Ptyp_constr ( Lident "unit", [])
)
})
; pvb_attributes = __attrs
; pvb_loc = __loc
}
]
)
|}]
(* As expected here, the matching constraint from the pattern and expression or
recombined into a single value constraint with locally abstract univars set
correctly. *)
(* --------- coercion to pvb_constraint --------- *)
(*TODO*)
[%%expect{|
|}]
|
