68 lines
2.6 KiB
C++
68 lines
2.6 KiB
C++
|
/*
|
||
|
|
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
|
||
|
|
Released under Apache 2.0 license as described in the file LICENSE.
|
||
|
|
|
||
|
|
Author: Leonardo de Moura
|
||
|
|
*/
|
||
|
|
#include "kernel/abstract.h"
|
||
|
|
#include "library/locals.h"
|
||
|
|
#include "library/tactic/tactic.h"
|
||
|
|
#include "library/tactic/expr_to_tactic.h"
|
||
|
|
|
||
|
|
namespace lean {
|
||
|
|
tactic clear_tactic(name const & n) {
|
||
|
|
auto fn = [=](environment const &, io_state const &, proof_state const & s) -> optional<proof_state> {
|
||
|
|
goals const & gs = s.get_goals();
|
||
|
|
if (empty(gs))
|
||
|
|
return none_proof_state();
|
||
|
|
goal g = head(gs);
|
||
|
|
goals tail_gs = tail(gs);
|
||
|
|
expr meta = g.get_meta();
|
||
|
|
buffer<expr> locals;
|
||
|
|
get_app_args(meta, locals);
|
||
|
|
unsigned i = locals.size();
|
||
|
|
while (i > 0) {
|
||
|
|
--i;
|
||
|
|
if (local_pp_name(locals[i]) == n) {
|
||
|
|
// found target
|
||
|
|
name real_n = mlocal_name(locals[i]);
|
||
|
|
for (unsigned j = i+1; j < locals.size(); j++) {
|
||
|
|
if (contains_local(mlocal_type(locals[j]), real_n))
|
||
|
|
return none_proof_state(); // other variables depends on n
|
||
|
|
}
|
||
|
|
if (contains_local(g.get_type(), real_n))
|
||
|
|
return none_proof_state(); // type depends on n
|
||
|
|
buffer<expr> new_locals;
|
||
|
|
for (unsigned j = 0; j < i; j++)
|
||
|
|
new_locals.push_back(locals[j]);
|
||
|
|
for (unsigned j = i+1; j < locals.size(); j++)
|
||
|
|
new_locals.push_back(locals[j]);
|
||
|
|
name_generator ngen = s.get_ngen();
|
||
|
|
expr new_meta = mk_app(mk_metavar(ngen.next(), Pi(new_locals, g.get_type())), new_locals);
|
||
|
|
goal new_g(new_meta, g.get_type());
|
||
|
|
expr val = Fun(locals, new_meta);
|
||
|
|
substitution new_subst = s.get_subst();
|
||
|
|
new_subst.assign(g.get_name(), val);
|
||
|
|
proof_state new_s(s, goals(new_g, tail_gs), new_subst, ngen);
|
||
|
|
return some_proof_state(new_s);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return none_proof_state();
|
||
|
|
};
|
||
|
|
return tactic01(fn);
|
||
|
|
}
|
||
|
|
|
||
|
|
static name const & get_clear_arg(expr const & e) {
|
||
|
|
return tactic_expr_to_id(e, "invalid 'clear' tactic, argument must be an identifier");
|
||
|
|
}
|
||
|
|
|
||
|
|
void initialize_clear_tactic() {
|
||
|
|
register_tac(name({"tactic", "clear"}),
|
||
|
|
[](type_checker &, elaborate_fn const &, expr const & e, pos_info_provider const *) {
|
||
|
|
name n = get_clear_arg(app_arg(e));
|
||
|
|
return clear_tactic(n);
|
||
|
|
});
|
||
|
|
}
|
||
|
|
void finalize_clear_tactic() {}
|
||
|
|
}
|