/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.

Author: Leonardo de Moura
*/
#pragma once
#include "util/lua.h"
#include "kernel/expr.h"

namespace lean {
/**
   \brief Matching for higher-order patterns. Return true iff \c t matches the higher-order pattern \c p.
   The substitution is stored in \c subst.

   \c subst is an assignment for the free variables occurring in \c p.

   The free variables occurring in \c t are treated as constants.

   We say non-free variables occurring in \c p and \c t are "locally bound".

   \c p is a higher-order pattern when in all applications in \c p
      1- A free variable is to the function OR
      2- A free variable is the function, but all other arguments are distinct locally bound variables.

   \pre \c subst must be big enough to store all free variables occurring in subst
*/
bool hop_match(expr const & p, expr const & t, buffer<optional<expr>> & subst);
void open_hop_match(lua_State * L);
}