44 lines
1.4 KiB
C++
44 lines
1.4 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_expr.h"
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#include "library/tactic/tactic_state.h"
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namespace lean {
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vm_obj change(expr const & e, tactic_state const & s) {
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try {
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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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type_context ctx = mk_type_context_for(s);
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if (ctx.is_def_eq(e, g->get_type())) {
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auto mctx = ctx.mctx();
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expr new_M = mctx.mk_metavar_decl(g->get_context(), e);
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mctx.assign(head(s.goals()), new_M);
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list<expr> new_gs(new_M, tail(s.goals()));
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return mk_tactic_success(set_mctx_goals(s, mctx, new_gs));
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} else {
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format m("tactic.change failed, given type");
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m += pp_indented_expr(s, e);
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m += format("is not definitionally equal to");
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m += pp_indented_expr(s, g->get_type());
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return mk_tactic_exception(m, s);
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}
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} catch (exception & e) {
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return mk_tactic_exception(e, s);
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}
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}
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vm_obj tactic_change(vm_obj const & e, vm_obj const & s) {
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return change(to_expr(e), to_tactic_state(s));
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}
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void initialize_change_tactic() {
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DECLARE_VM_BUILTIN(name({"tactic", "change"}), tactic_change);
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}
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void finalize_change_tactic() {
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}
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}
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