74 lines
2.5 KiB
C++
74 lines
2.5 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 <vector>
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#include "kernel/abstract.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 n, expr const * subst) {
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lean_assert(std::all_of(subst, subst+n, [](expr const & e) { return !has_loose_bvars(e) && is_fvar(e); }));
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if (!has_fvar(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_fvar(m))
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return some_expr(m); // expression m does not contain free variables
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if (is_fvar(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 (fvar_name(subst[i]) == fvar_name(m))
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return some_expr(mk_bvar(offset + n - i - 1));
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}
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return none_expr();
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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, name const & n) {
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expr fvar = mk_fvar(n);
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return abstract(e, 1, &fvar);
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}
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static object * lean_expr_abstract_core(object * e0, size_t n, object * subst) {
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lean_assert(n <= lean_array_size(subst));
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expr const & e = reinterpret_cast<expr const &>(e0);
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if (!has_fvar(e)) {
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lean_inc(e0);
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return e0;
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}
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expr r = replace(e, [=](expr const & m, unsigned offset) -> optional<expr> {
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if (!has_fvar(m))
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return some_expr(m); // expression m does not contain free variables
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if (is_fvar(m)) {
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size_t i = n;
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while (i > 0) {
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--i;
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object * v = lean_array_get_core(subst, i);
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if (is_fvar_core(v) && fvar_name_core(v) == fvar_name(m))
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return some_expr(mk_bvar(offset + n - i - 1));
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}
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return none_expr();
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}
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return none_expr();
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});
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return r.steal();
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}
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extern "C" object * lean_expr_abstract_range(object * e, object * n, object * subst) {
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if (!lean_is_scalar(n))
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return lean_expr_abstract_core(e, lean_array_size(subst), subst);
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else
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return lean_expr_abstract_core(e, std::min(lean_unbox(n), lean_array_size(subst)), subst);
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}
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extern "C" object * lean_expr_abstract(object * e, object * subst) {
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return lean_expr_abstract_core(e, lean_array_size(subst), subst);
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}
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}
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