lean2/src/kernel/abstract.cpp

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

Author: Leonardo de Moura
*/
#include <algorithm>
#include "abstract.h"
#include "free_vars.h"
#include "replace.h"

namespace lean {
expr abstract(expr const & e, unsigned n, expr const * s) {
    lean_assert(std::all_of(s, s+n, closed));

    auto f = [=](expr const & e, unsigned offset) -> expr {
        unsigned i = n;
        while (i > 0) {
            --i;
            if (s[i] == e)
                return mk_var(offset + n - i - 1);
        }
        return e;
    };

    return replace_fn<decltype(f)>(f)(e);
}
expr abstract_p(expr const & e, unsigned n, expr const * s) {
    lean_assert(std::all_of(s, s+n, closed));

    auto f = [=](expr const & e, unsigned offset) -> expr {
        unsigned i = n;
        while (i > 0) {
            --i;
            if (is_eqp(s[i], e))
                return mk_var(offset + n - i - 1);
        }
        return e;
    };

    return replace_fn<decltype(f)>(f)(e);
}
#define MkBinder(FName)                                                 \
expr FName(std::initializer_list<std::pair<expr const &, expr const &>> const & l, expr const & b) { \
    expr r = b;                                                         \
    auto it = l.end();                                                  \
    while (it != l.begin()) {                                           \
        --it;                                                           \
        auto const & p = *it;                                           \
        r = FName(p.first, p.second, r);                                \
    }                                                                   \
    return r;                                                           \
}

MkBinder(Fun);
MkBinder(Pi);
MkBinder(Let);
}