69 lines
2.4 KiB
C++
69 lines
2.4 KiB
C++
/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include <algorithm>
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#include <utility>
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#include "kernel/abstract.h"
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#include "kernel/free_vars.h"
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#include "kernel/replace_fn.h"
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namespace lean {
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expr abstract(expr const & e, unsigned s, unsigned n, expr const * subst) {
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lean_assert(std::all_of(subst, subst+n, closed));
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return replace(e, [=](expr const & e, unsigned offset) -> optional<expr> {
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if (closed(e)) {
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unsigned i = n;
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while (i > 0) {
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--i;
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if (subst[i] == e)
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return some_expr(copy_tag(e, mk_var(offset + s + n - i - 1)));
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}
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}
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return none_expr();
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});
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}
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expr abstract(expr const & e, unsigned n, expr const * subst) { return abstract(e, 0, n, subst); }
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expr abstract(expr const & e, expr const & s, unsigned i) { return abstract(e, i, 1, &s); }
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expr abstract_locals(expr const & e, unsigned n, expr const * subst) {
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lean_assert(std::all_of(subst, subst+n, [](expr const & e) { return closed(e) && is_local(e); }));
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if (!has_local(e))
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return e;
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return replace(e, [=](expr const & m, unsigned offset) -> optional<expr> {
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if (!has_local(m))
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return some_expr(m); // expression m does not contain local constants
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if (is_local(m)) {
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unsigned i = n;
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while (i > 0) {
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--i;
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if (mlocal_name(subst[i]) == mlocal_name(m))
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return some_expr(copy_tag(m, mk_var(offset + n - i - 1)));
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}
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}
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return none_expr();
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});
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}
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template<bool is_lambda>
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expr mk_binding(unsigned num, expr const * locals, expr const & b) {
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expr r = abstract_locals(b, num, locals);
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unsigned i = num;
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while (i > 0) {
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--i;
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expr const & l = locals[i];
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expr t = abstract_locals(mlocal_type(l), i, locals);
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if (is_lambda)
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r = mk_lambda(local_pp_name(l), t, r, local_info(l));
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else
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r = mk_pi(local_pp_name(l), t, r, local_info(l));
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}
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return r;
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}
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expr Pi(unsigned num, expr const * locals, expr const & b) { return mk_binding<false>(num, locals, b); }
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expr Fun(unsigned num, expr const * locals, expr const & b) { return mk_binding<true>(num, locals, b); }
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}
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