/*
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.

Author: Leonardo de Moura
*/
#pragma once
#include <functional>
#include "kernel/type_checker.h"

namespace lean {
/** \brief Return the \c e normal form with respect to the environment \c env.
    Any unification constraint generated in the process is discarded.

    \remark Unification constraints are only generated if \c e contains meta-variables.
*/
expr normalize(environment const & env, expr const & e, bool eta = false);
expr normalize(environment const & env, level_param_names const & ls, expr const & e, bool eta = false);
/** \brief Similar to <tt>expr normalize(environment const & env, expr const & e)</tt>, but
    uses the converter associated with \c tc. */
expr normalize(type_checker & tc, expr const & e, bool eta = false);
expr normalize(type_checker & tc, level_param_names const & ls, expr const & e, bool eta = false);
/** \brief Return the \c e normal form with respect to \c tc, and store generated constraints
    into \c cs.
*/
expr normalize(type_checker & tc, expr const & e, constraint_seq & cs, bool eta = false);
/** \brief Return the \c e normal form with respect to \c tc, and store generated constraints
    into \c cs.

    \remark A sub-expression is evaluated only if \c pred returns true.
*/
expr normalize(type_checker & tc, expr const & e, std::function<bool(expr const&)> const & pred, // NOLINT
               constraint_seq & cs, bool eta = false);

/** \brief c_unfold hint instructs the normalizer (and simplifier) that
    a function application (f a_1 ... a_i ... a_n) should be unfolded
    when argument a_i is a constructor.

    The constant will be unfolded even if it the whnf procedure did not unfolded it.

    Of course, kernel opaque constants are not unfolded.

    \remark If idx is none, then the hint is removed.
*/
environment add_unfold_c_hint(environment const & env, name const & n, optional<unsigned> idx, bool persistent = true);
inline environment add_unfold_c_hint(environment const & env, name const & n, unsigned idx, bool persistent = true) {
    return add_unfold_c_hint(env, n, optional<unsigned>(idx), persistent);
}
inline environment erase_unfold_c_hint(environment const & env, name const & n, bool persistent = true) {
    return add_unfold_c_hint(env, n, optional<unsigned>(), persistent);
}

/** \brief Retrieve the hint added with the procedure add_unfold_c_hint. */
optional<unsigned> has_unfold_c_hint(environment const & env, name const & d);

void initialize_normalize();
void finalize_normalize();
}