Library Ltac2.Fresh


Require Import Ltac2.Init.
Require Ltac2.Control.
Require Ltac2.List.

Module Free.

Ltac2 Type t.
Type of sets of free variables

Ltac2 @external empty : t := "rocq-runtime.plugins.ltac2" "fresh_free_empty".

Ltac2 @external add : ident -> t -> t := "rocq-runtime.plugins.ltac2" "fresh_free_add".

Ltac2 @external union : t -> t -> t := "rocq-runtime.plugins.ltac2" "fresh_free_union".

Ltac2 @external of_ids : ident list -> t := "rocq-runtime.plugins.ltac2" "fresh_free_of_ids".

Ltac2 @external of_constr : constr -> t := "rocq-runtime.plugins.ltac2" "fresh_free_of_constr".

Ltac2 of_goal () := of_ids (List.map (fun (id, _, _) => id) (Control.hyps ())).

End Free.

Generate a fresh identifier with the given base name which is not a member of the provided set of free variables, and update the set. More efficient than composing fresh and Free.add.
Ltac2 @external next : Free.t -> ident -> ident * Free.t := "rocq-runtime.plugins.ltac2" "fresh_next".

Generate a fresh identifier with the given base name which is not a member of the provided set of free variables.
Ltac2 @external fresh : Free.t -> ident -> ident := "rocq-runtime.plugins.ltac2" "fresh_fresh".

Ltac2 in_goal id := Fresh.fresh (Free.of_goal ()) id.