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(*  The Why3 Verification Platform   /   The Why3 Development Team  *)
(*  Copyright 2010-2022 --  Inria - CNRS - Paris-Saclay University  *)
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(*  This software is distributed under the terms of the GNU Lesser  *)
(*  General Public License version 2.1, with the special exception  *)
(*  on linking described in file LICENSE.                           *)
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(* Handling of attributes *)

val intro_projections_counterexmp :  Env.env -> Task.task Trans.trans
 (**
    Transformation that for each declared abstract function or predicate
    p tagged with attribute "model_projected" creates a declaration of
    new constant c tagged with attribute "model" and declaration of new
    axiom stating that c = f p where f is projection for p.

    Projections are composed from projection functions. Projection function
    is a function with a single argument tagged with metas "model_projection".
    Projection f for abstract function or predicate p is defined as:
    f = pf_n ... pf_1 id where id is identity function and pf_i for i = 1 .. n
    are projection functions for that it holds that the argument of pf_1 is of
    the same type as p, the return value of pf_i is of the same type as the
    argument of pf_i+1, for all i, j = 1 .. n pf_i <> pf_j, and there is no
    projection function pf that could further project f. That is, projection
    for p is identify if there is no projection function with an argument
    of the same type as p.

    Projections can be given names by tagging projection function by
    an attribute of the form "model_trace:proj_name". If predicate p
    has an attribute of the form "model_trace:p_name@*", the constant
    will have an attribute of the form "model_trace:p_nameproj_name@*".
    This is especially usefull when projetions are projecting record type
    to its elements (there is one projection for every record element with
    name ".record_element_name").

    Note that in order this work, projection functions cannot be inlined.
    If inlining transformation is performed, projection functions must
    be marked with meta "inline:no".

    This transformation is needed in situations when we want to display
    not value of a variable, but value of a projection function applied to
    a variable. This is needed, e.g., in cases when the type of a variable
    is abstract.

    Note that since Why3 supports namespaces (different projection functions
    can have the same name) and input languages of solvers typically not,
    Why3 renames projection functions to avoid name clashes. This is why
    it is not possible to just store the name of the projection function
    in an attribute and than query the solver directly for the value of
    the projection. Also, it means that this transformation must be
    executed before this renaming.
 *)

val intro_const_equal_to_term :
  term : Term.term ->
  id_new : Ident.preid ->
  axiom_name : string ->
  Decl.decl list
(** Creates declaration of new constant and declaration of axiom
    stating that the constant is equal to given term.

    @param term the term to which the new constant will be equal
    @param id_new the preid composed of the name, attribute
           and location of the constant
    @param axiom_name the name of the axiom about the constant
    @return the definition of the constant and axiom about the constant
*)
