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(************************************************************************)
(* * The Coq Proof Assistant / The Coq Development Team *)
(* v * Copyright INRIA, CNRS and contributors *)
(* <O___,, * (see version control and CREDITS file for authors & dates) *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(* * (see LICENSE file for the text of the license) *)
(************************************************************************)
Require Import Ltac2.Message.
(** This file defines a printf notation for easiness of writing messages *)
(**
The built-in "format" notation scope can be used to create well-typed variadic
printing commands following a printf-like syntax. The "format" scope parses
quoted strings which contain either raw string data or printing
specifications. Raw strings will be output verbatim as if they were passed
to Ltac2.Message.of_string.
Printing specifications are of the form
<< '%' type >>
where the type value defines which kind of arguments will be accepted and
how they will be printed. They can take the following values.
- << i >>: takes an argument of type int and behaves as Message.of_int
- << I >>: takes an argument of type ident and behaves as Message.of_ident
- << s >>: takes an argument of type string and behaves as Message.of_string
- << t >>: takes an argument of type constr and behaves as Message.of_constr
- << a >>: takes two arguments << f >> of type << (unit -> 'a -> message) >>
and << x >> of type << 'a >> and behaves as << f () x >>
- << % >>: outputs << % >> verbatim
TODO: add printing modifiers.
*)
Ltac2 printf fmt := Format.kfprintf print fmt.
Ltac2 fprintf fmt := Format.kfprintf (fun x => x) fmt.
(** The two following notations are made available when this module is imported.
- printf will parse a format and generate a function taking the
corresponding arguments ant printing the resulting message as per
Message.print. In particular when fully applied it has type unit.
- fprintf behaves similarly but return the message as a value instead of
printing it.
*)
Ltac2 Notation "printf" fmt(format) := printf fmt.
Ltac2 Notation "fprintf" fmt(format) := fprintf fmt.
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