91 lines
3.4 KiB
C++
91 lines
3.4 KiB
C++
/*
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Copyright (c) 2016 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 "library/vm/vm_name.h"
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#include "library/vm/vm_expr.h"
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#include "library/tactic/tactic_state.h"
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namespace lean {
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expr clear(metavar_context & mctx, expr const & mvar, expr const & H) {
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lean_assert(is_metavar(mvar));
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lean_assert(is_local(H));
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optional<metavar_decl> g = mctx.find_metavar_decl(mvar);
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if (!g) throw exception("clear tactic failed, there are no goals to be solved");
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local_context lctx = g->get_context();
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optional<local_decl> d = lctx.find_local_decl(H);
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if (!d)
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throw exception(sstream() << "clear tactic failed, unknown '" << local_pp_name(H) << "' hypothesis");
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/* We don't need to traverse let-declarations because the lctx.has_dependencies(*d, mctx) will catch them. */
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if (depends_on(g->get_type(), mctx, 1, &H))
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throw exception(sstream() << "clear tactic failed, target type depends on '" << local_pp_name(H) << "'");
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if (optional<local_decl> d2 = lctx.has_dependencies(*d, mctx))
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throw exception(sstream() << "clear tactic failed, hypothesis '" << d2->get_pp_name() << "' depends on '" << local_pp_name(H) << "'");
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lctx.clear(*d);
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expr new_mvar = mctx.mk_metavar_decl(lctx, g->get_type());
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mctx.assign(mvar, new_mvar);
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return new_mvar;
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}
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expr clear_rec_core(metavar_context & mctx, expr const & mvar) {
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optional<metavar_decl> g = mctx.find_metavar_decl(mvar);
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lean_assert(g);
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local_context lctx = g->get_context();
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if (optional<local_decl> d = lctx.find_if([](local_decl const & d) { return d.get_info().is_rec(); })) {
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return clear(mctx, mvar, d->mk_ref());
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} else {
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return mvar;
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}
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}
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expr clear_recs(metavar_context & mctx, expr const & mvar) {
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expr curr = mvar;
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while (true) {
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expr next = clear_rec_core(mctx, curr);
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if (next == curr)
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return curr;
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curr = next;
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}
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}
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vm_obj clear(expr const & H, tactic_state const & s) {
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lean_assert(is_local(H));
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try {
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optional<expr> mvar = s.get_main_goal();
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if (!mvar) return mk_no_goals_exception(s);
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metavar_context mctx = s.mctx();
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expr new_mvar = clear(mctx, *mvar, H);
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return tactic::mk_success(set_mctx_goals(s, mctx, cons(new_mvar, tail(s.goals()))));
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} catch (exception & ex) {
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return tactic::mk_exception(ex, s);
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}
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}
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vm_obj clear_internal(name const & n, tactic_state const & s) {
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optional<metavar_decl> g = s.get_main_goal_decl();
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if (!g) return mk_no_goals_exception(s);
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metavar_context mctx = s.mctx();
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local_context lctx = g->get_context();
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optional<local_decl> d = lctx.find_local_decl(n);
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if (!d)
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return tactic::mk_exception(sstream() << "clear tactic failed, unknown '" << n << "' hypothesis", s);
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return clear(d->mk_ref(), s);
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}
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vm_obj tactic_clear(vm_obj const & e0, vm_obj const & s) {
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expr const & e = to_expr(e0);
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if (!is_local(e))
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return tactic::mk_exception(sstream() << "clear tactic failed, given expression is not a local constant",
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tactic::to_state(s));
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return clear(e, tactic::to_state(s));
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}
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void initialize_clear_tactic() {
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DECLARE_VM_BUILTIN(name({"tactic", "clear"}), tactic_clear);
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}
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void finalize_clear_tactic() {
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}
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}
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