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feat(library/init/meta): implement unfold tactics in Lean using new building blocks

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This commit is contained in:
Leonardo de Moura 2016-10-12 17:15:43 -07:00
parent 9320016b97
commit ef23c591fc
13 changed files with 152 additions and 457 deletions
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2
library/init/meta/default.lean
View file

@ -9,7 +9,7 @@ import init.meta.level init.meta.expr init.meta.environment init.meta.attribute
import init.meta.tactic init.meta.contradiction_tactic init.meta.constructor_tactic
import init.meta.injection_tactic init.meta.relation_tactics init.meta.fun_info
import init.meta.congr_lemma init.meta.match_tactic init.meta.ac_tactics
import init.meta.backward init.meta.rewrite_tactic init.meta.unfold_tactic
import init.meta.backward init.meta.rewrite_tactic
import init.meta.mk_dec_eq_instance init.meta.mk_inhabited_instance
import init.meta.simp_tactic init.meta.set_get_option_tactics
import init.meta.interactive init.meta.converter

24
library/init/meta/interactive.lean
View file

@ -318,5 +318,29 @@ to_expr q >>= tactic.subst >> try reflexivity
meta def clear : raw_ident_list → tactic unit :=
tactic.clear_lst
private meta def dunfold_hyps : list name → location → tactic unit
| cs [] := skip
| cs (h::hs) := get_local h >>= dunfold_at cs >> dunfold_hyps cs hs
meta def dunfold : raw_ident_list → location → tactic unit
| cs [] := tactic.dunfold cs
| cs hs := dunfold_hyps cs hs
/- TODO(Leo): add support for non-refl lemmas -/
meta def unfold : raw_ident_list → location → tactic unit :=
dunfold
private meta def dunfold_hyps_occs : name → occurrences → location → tactic unit
| c occs [] := skip
| c occs (h::hs) := get_local h >>= dunfold_core_at occs [c] >> dunfold_hyps_occs c occs hs
meta def dunfold_occs : ident → list nat → location → tactic unit
| c ps [] := tactic.dunfold_occs_of ps c
| c ps hs := dunfold_hyps_occs c (occurrences.pos ps) hs
/- TODO(Leo): add support for non-refl lemmas -/
meta def unfold_occs : ident → list nat → location → tactic unit :=
dunfold_occs
end interactive
end tactic

5
library/init/meta/occurrences.lean
View file

@ -25,6 +25,11 @@ inductive occurrences
open occurrences
def occurrences.contains : occurrences → nat → bool
| all p := tt
| (occurrences.pos ps) p := to_bool (p ∈ ps)
| (occurrences.neg ps) p := to_bool (p ∉ ps)
instance : inhabited occurrences :=
⟨all⟩

57
library/init/meta/simp_tactic.lean
View file

@ -5,7 +5,7 @@ Authors: Leonardo de Moura
-/
prelude
import init.meta.tactic init.meta.attribute init.meta.constructor_tactic
import init.meta.relation_tactics
import init.meta.relation_tactics init.meta.occurrences
open tactic
@ -68,11 +68,15 @@ meta constant simp_lemmas.simplify_core : simp_lemmas → tactic unit → name
The resulting expression is definitionally equal to the input. -/
meta constant simp_lemmas.dsimplify_core (max_steps : nat) (visit_instances : bool) : simp_lemmas → expr → tactic expr
meta def default_max_steps := 10000000
meta def simp_lemmas.dsimplify : simp_lemmas → expr → tactic expr :=
simp_lemmas.dsimplify_core 1000000 ff
simp_lemmas.dsimplify_core default_max_steps ff
namespace tactic
meta constant dsimplify_core
{A : Type}
(a : A)
(max_steps : nat)
/- If visit_instances = ff, then instance implicit arguments are not visited, but
tactic will canonize them. -/
@ -80,19 +84,22 @@ meta constant dsimplify_core
/- (pre e) is invoked before visiting the children of subterm 'e',
if it succeeds the result is a new expression that must be definitionally equal to 'e',
and a flag indicating whether the new children should be visited or not. -/
(pre : expr → tactic (expr × bool))
(pre : A → expr → tactic (A × expr × bool))
/- (post e) is invoked after visiting the children of subterm 'e',
if it succeeds the result is a new expression that must be definitionally equal to 'e',
and a flag indicating whether the new children should be revisited.
Remark: if (pre e) returns (some (new_e, ff)), then post is not invoked for new_e. -/
(post : expr → tactic (expr × bool))
: expr → tactic expr
(post : A → expr → tactic (A × expr × bool))
: expr → tactic (A × expr)
meta def dsimplify
(pre : expr → tactic (expr × bool))
(post : expr → tactic (expr × bool))
: expr → tactic expr :=
dsimplify_core 1000000 ff pre post
λ e, do (a, new_e) ← dsimplify_core () default_max_steps ff
(λ u e, do r ← pre e, return (u, r))
(λ u e, do r ← post e, return (u, r)) e,
return new_e
meta constant dunfold_expr_core : transparency → expr → tactic expr
@ -104,6 +111,44 @@ meta constant unfold_projection_core : transparency → expr → tactic expr
meta def unfold_projection : expr → tactic expr :=
unfold_projection_core reducible
meta def dunfold_occs_core (m : transparency) (max_steps : nat) (occs : occurrences) (cs : list name) (e : expr) : tactic expr :=
let unfold (c : nat) (e : expr) : tactic (nat × expr × bool) := do
guard (cs^.any e^.is_app_of),
new_e ← dunfold_expr_core m e,
if occs^.contains c
then return (c+1, new_e, tt)
else return (c+1, e, tt)
in do (c, new_e) ← dsimplify_core 1 max_steps tt unfold (λ c e, failed) e,
return new_e
meta def dunfold_core (m : transparency) (max_steps : nat) (cs : list name) (e : expr) : tactic expr :=
let unfold (u : unit) (e : expr) : tactic (unit × expr × bool) := do
guard (cs^.any e^.is_app_of),
new_e ← dunfold_expr_core m e,
return (u, new_e, tt)
in do (c, new_e) ← dsimplify_core () max_steps tt (λ c e, failed) unfold e,
return new_e
meta def dunfold : list name → tactic unit :=
λ cs, target >>= dunfold_core reducible default_max_steps cs >>= change
meta def dunfold_occs_of (occs : list nat) (c : name) : tactic unit :=
target >>= dunfold_occs_core reducible default_max_steps (occurrences.pos occs) [c] >>= change
meta def dunfold_core_at (occs : occurrences) (cs : list name) (h : expr) : tactic unit :=
do num_reverted : ℕ ← revert h,
(expr.pi n bi d b : expr) ← target | failed,
new_d : expr ← dunfold_occs_core reducible default_max_steps occs cs d,
change $ expr.pi n bi new_d b,
intron num_reverted
meta def dunfold_at (cs : list name) (h : expr) : tactic unit :=
do num_reverted : ℕ ← revert h,
(expr.pi n bi d b : expr) ← target | failed,
new_d : expr ← dunfold_core reducible default_max_steps cs d,
change $ expr.pi n bi new_d b,
intron num_reverted
meta def simplify (prove_fn : tactic unit) (extra_lemmas : list expr) (e : expr) : tactic (expr × expr) :=
do lemmas ← simp_lemmas.mk_default,
new_lemmas ← lemmas^.append extra_lemmas,

32
library/init/meta/unfold_tactic.lean
View file

@ -1,32 +0,0 @@
/-
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
prelude
import init.meta.relation_tactics init.meta.occurrences
namespace tactic
/- (rewrite_core m use_instances occs symm H) -/
meta constant unfold_expr_core : bool → occurrences → list name → expr → tactic expr
meta def unfold_core (force : bool) (occs : occurrences) (ns : list name) : tactic unit :=
target >>= unfold_expr_core force occs ns >>= change
meta def unfold : list name → tactic unit :=
unfold_core ff occurrences.all
meta def unfold_occs_of (occs : list nat) (c : name) : tactic unit :=
unfold_core ff (occurrences.pos occs) [c]
meta def unfold_core_at (force : bool) (occs : occurrences) (ns : list name) (H : expr) : tactic unit :=
do num_reverted : ℕ ← revert H,
(expr.pi n bi d b : expr) ← target | failed,
new_H : expr ← unfold_expr_core force occs ns d,
change $ expr.pi n bi new_H b,
intron num_reverted
meta def unfold_at : list name → expr → tactic unit :=
unfold_core_at ff occurrences.all
end tactic

21
src/library/tactic/dsimplify.cpp
View file

@ -237,19 +237,22 @@ dsimplify_fn::dsimplify_fn(type_context & ctx, unsigned max_steps, bool visit_in
}
class tactic_dsimplify_fn : public dsimplify_core_fn {
vm_obj m_a;
vm_obj m_pre;
vm_obj m_post;
tactic_state m_s;
optional<pair<expr, bool>> invoke_fn(vm_obj const & fn, expr const & e) {
m_s = set_mctx_lctx(m_s, m_ctx.mctx(), m_ctx.lctx());
vm_obj r = invoke(fn, to_obj(e), to_obj(m_s));
vm_obj r = invoke(fn, m_a, to_obj(e), to_obj(m_s));
if (optional<tactic_state> new_s = is_tactic_success(r)) {
m_s = *new_s;
m_ctx.set_mctx(m_s.mctx());
vm_obj p = cfield(r, 0);
expr new_e = to_expr(cfield(p, 0));
bool flag = to_bool(cfield(p, 1));
m_a = cfield(p, 0);
vm_obj p1 = cfield(p, 1);
expr new_e = to_expr(cfield(p1, 0));
bool flag = to_bool(cfield(p1, 1));
return optional<pair<expr, bool>>(new_e, flag);
} else {
return optional<pair<expr, bool>>();
@ -266,23 +269,27 @@ class tactic_dsimplify_fn : public dsimplify_core_fn {
public:
tactic_dsimplify_fn(type_context & ctx, unsigned max_steps, bool visit_instances,
vm_obj const & pre, vm_obj const & post):
vm_obj const & a, vm_obj const & pre, vm_obj const & post):
dsimplify_core_fn(ctx, max_steps, visit_instances),
m_a(a),
m_pre(pre),
m_post(post),
m_s(mk_tactic_state_for(ctx.env(), ctx.get_options(), ctx.mctx(), ctx.lctx(), mk_true())) {
}
vm_obj const & get_a() const { return m_a; }
};
vm_obj tactic_dsimplify_core(vm_obj const & max_steps, vm_obj const & visit_instances,
vm_obj tactic_dsimplify_core(vm_obj const &, vm_obj const & a,
vm_obj const & max_steps, vm_obj const & visit_instances,
vm_obj const & pre, vm_obj const & post, vm_obj const & e, vm_obj const & s) {
try {
type_context ctx = mk_type_context_for(to_tactic_state(s));
tactic_dsimplify_fn F(ctx, force_to_unsigned(max_steps, std::numeric_limits<unsigned>::max()),
to_bool(visit_instances), pre, post);
to_bool(visit_instances), a, pre, post);
expr new_e = F(to_expr(e));
tactic_state new_s = set_mctx(to_tactic_state(s), F.mctx());
return mk_tactic_success(to_obj(new_e), new_s);
return mk_tactic_success(mk_vm_pair(F.get_a(), to_obj(new_e)), new_s);
} catch (exception & ex) {
return mk_tactic_exception(ex, to_tactic_state(s));
}

408
src/library/tactic/unfold_tactic.cpp
View file

@ -4,414 +4,15 @@ Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "util/fresh_name.h"
#include "kernel/abstract.h"
#include "kernel/instantiate.h"
#include "kernel/inductive/inductive.h"
#include "library/util.h"
#include "library/trace.h"
#include "library/type_context.h"
#include "library/replace_visitor.h"
#include "library/constants.h"
#include "library/user_recursors.h"
#include "library/vm/vm_list.h"
#include "library/vm/vm_expr.h"
#include "library/tactic/eqn_lemmas.h"
#include "library/tactic/tactic_state.h"
#include "library/tactic/occurrences.h"
namespace lean {
/* Auxiliary visitor the implements the common parts for unfold_rec_fn and fold_rec_fn. */
class replace_visitor_aux : public replace_visitor {
protected:
virtual type_context & ctx() = 0;
expr visit_app_default(expr const & e, expr const & fn, buffer<expr> & args) {
bool modified = false;
for (expr & arg : args) {
expr new_arg = visit(arg);
if (arg != new_arg)
modified = true;
arg = new_arg;
}
if (!modified)
return e;
return mk_app(fn, args);
}
virtual expr visit_binding(expr const & b) override {
expr new_domain = visit(binding_domain(b));
type_context::tmp_locals locals(ctx());
expr l = locals.push_local(binding_name(b), new_domain, binding_info(b));
expr new_body = ctx().abstract_locals(visit(instantiate(binding_body(b), l)), 1, &l);
return update_binding(b, new_domain, new_body);
}
};
class unfold_rec_fn : public replace_visitor_aux {
environment const & m_env;
bool m_force_unfold;
type_context & m_ctx;
list<name> m_to_unfold;
occurrences m_occs;
unsigned m_occ_idx;
static void throw_ill_formed() {
throw exception("ill-formed expression");
}
virtual type_context & ctx() override { return m_ctx; }
bool is_rec_building_part(name const & n) {
if (n == get_prod_fst_name() || n == get_prod_snd_name())
return true;
if (is_user_defined_recursor(m_env, n))
return true;
if (n.is_atomic() || !n.is_string())
return false;
char const * str = n.get_string();
return
strcmp(str, "rec_on") == 0 ||
strcmp(str, "cases_on") == 0 ||
strcmp(str, "brec_on") == 0 ||
strcmp(str, "below") == 0 ||
strcmp(str, "no_confusion") == 0;
}
optional<unsigned> get_local_pos(buffer<expr> const & locals, expr const & e) {
if (!is_local(e))
return optional<unsigned>();
unsigned i = 0;
for (expr const & local : locals) {
if (mlocal_name(local) == mlocal_name(e))
return optional<unsigned>(i);
i++;
}
return optional<unsigned>();
}
/* Return true iff \c e is of the form (C.rec ...) */
bool is_rec_app(expr const & e, buffer<expr> const & locals, name & rec_name, buffer<unsigned> & indices_pos,
unsigned & main_arg_pos, buffer<unsigned> & rec_arg_pos) {
buffer<expr> args;
expr fn = get_app_args(e, args);
if (!is_constant(fn))
return false;
optional<name> I = inductive::is_elim_rule(m_env, const_name(fn));
rec_name = const_name(fn);
if (!I)
return false;
if (!is_recursive_datatype(m_env, *I))
return false;
unsigned major_idx = *inductive::get_elim_major_idx(m_env, const_name(fn));
unsigned nindices = *inductive::get_num_indices(m_env, *I);
lean_assert(nindices <= major_idx);
unsigned rel_idx = major_idx - nindices; // first index we should track
// Collect position of indices (at least the ones that occur in e)
while (rel_idx < args.size() && rel_idx < major_idx) {
if (auto it2 = get_local_pos(locals, args[rel_idx])) {
indices_pos.push_back(*it2);
} else {
return false;
}
rel_idx++;
}
if (major_idx >= args.size()) {
// Some indices and the major premise may not occur in e because of eta-reduction
main_arg_pos = locals.size() + major_idx - args.size();
for (unsigned i = rel_idx; i < major_idx; i++)
indices_pos.push_back(locals.size() + i - args.size());
return true;
}
if (auto it = get_local_pos(locals, args[major_idx])) {
main_arg_pos = *it;
} else {
return false;
}
for (unsigned i = major_idx+1; i < args.size(); i++) {
if (auto it2 = get_local_pos(locals, args[i])) {
rec_arg_pos.push_back(*it2);
} else {
return false;
}
}
return true;
}
enum rec_kind { BREC, REC, NOREC };
/* Try to detect the kind of recursive definition */
rec_kind get_rec_kind(expr const & e, buffer<expr> const & locals, name & rec_name,
buffer<unsigned> & indices_pos, unsigned & main_arg_pos, buffer<unsigned> & rec_arg_pos) {
// tout() << "get_rec_kind: " << e << "\n";
if (is_rec_app(e, locals, rec_name, indices_pos, main_arg_pos, rec_arg_pos))
return REC;
buffer<expr> args;
expr fn = get_app_args(e, args);
if (is_constant(fn) && const_name(fn) == get_prod_fst_name() &&
args.size() >= 3) {
// try do detect brec_on pattern
if (is_rec_app(args[2], locals, rec_name, indices_pos, main_arg_pos, rec_arg_pos) &&
// for brec, eta is not applicable, so main_arg_pos must be < locals.size()
main_arg_pos < locals.size()) {
for (unsigned i = 3; i < args.size(); i++) {
if (auto it2 = get_local_pos(locals, args[i])) {
rec_arg_pos.push_back(*it2);
} else {
return NOREC;
}
}
return BREC;
}
}
return NOREC;
}
/* Just unfold the application without trying to fold recursive call */
expr unfold_simple(expr const & fn, buffer<expr> & args) {
expr new_app = mk_app(fn, args);
if (auto r = unfold_term(m_env, new_app)) {
return visit(*r);
} else {
return new_app;
}
}
struct fold_failed {};
struct fold_rec_fn : public replace_visitor_aux {
type_context & m_ctx;
expr m_fn; // function being unfolded
buffer<expr> const & m_args; // arguments of the function being unfolded
rec_kind m_kind;
name m_rec_name;
unsigned m_major_idx; // position of the major premise in the recursor
buffer<unsigned> const & m_indices_pos; // position of the datatype indices in the function being unfolded
unsigned m_main_pos; // position of the (recursive) argument in the function being unfolded
buffer<unsigned> const & m_rec_arg_pos; // position of the other arguments that are not fixed in the recursion
name m_prod_rec_name;
fold_rec_fn(type_context & ctx, expr const & fn, buffer<expr> const & args, rec_kind k, name const & rec_name,
buffer<unsigned> const & indices_pos, unsigned main_pos, buffer<unsigned> const & rec_arg_pos):
m_ctx(ctx), m_fn(fn), m_args(args), m_kind(k), m_rec_name(rec_name),
m_major_idx(*inductive::get_elim_major_idx(m_ctx.env(), rec_name)),
m_indices_pos(indices_pos),
m_main_pos(main_pos), m_rec_arg_pos(rec_arg_pos) {
m_prod_rec_name = inductive::get_elim_name(get_prod_name());
lean_assert(m_main_pos < args.size());
lean_assert(std::all_of(rec_arg_pos.begin(), rec_arg_pos.end(), [&](unsigned pos) { return pos < args.size(); }));
}
virtual type_context & ctx() override { return m_ctx; }
expr fold_rec(expr const & e, buffer<expr> const & args) {
if (args.size() != m_major_idx + 1 + m_rec_arg_pos.size())
throw fold_failed();
buffer<expr> new_args;
new_args.append(m_args);
unsigned nindices = m_indices_pos.size();
for (unsigned i = 0; i < m_indices_pos.size(); i++) {
new_args[m_indices_pos[i]] = args[m_major_idx - nindices + i];
}
new_args[m_main_pos] = args[m_major_idx];
for (unsigned i = 0; i < m_rec_arg_pos.size(); i++) {
new_args[m_rec_arg_pos[i]] = args[m_major_idx + 1 + i];
}
expr folded_app = mk_app(m_fn, new_args);
if (!m_ctx.is_def_eq(folded_app, e))
throw fold_failed();
return folded_app;
}
expr fold_brec_core(expr const & e, buffer<expr> const & args, unsigned prefix_size, unsigned major_pos) {
if (args.size() != prefix_size + m_rec_arg_pos.size()) {
throw fold_failed();
}
buffer<expr> nested_args;
get_app_args(args[major_pos], nested_args);
if (nested_args.size() != m_major_idx+1) {
throw fold_failed();
}
buffer<expr> new_args;
new_args.append(m_args);
unsigned nindices = m_indices_pos.size();
for (unsigned i = 0; i < m_indices_pos.size(); i++) {
new_args[m_indices_pos[i]] = nested_args[m_major_idx - nindices + i];
}
new_args[m_main_pos] = nested_args[m_major_idx];
for (unsigned i = 0; i < m_rec_arg_pos.size(); i++) {
new_args[m_rec_arg_pos[i]] = args[prefix_size + i];
}
expr folded_app = mk_app(m_fn, new_args);
if (!m_ctx.is_def_eq(folded_app, e))
throw fold_failed();
return folded_app;
}
expr fold_brec_fst(expr const & e, buffer<expr> const & args) {
return fold_brec_core(e, args, 3, 1);
}
expr fold_brec_prod_rec(expr const & e, buffer<expr> const & args) {
return fold_brec_core(e, args, 5, 4);
}
virtual expr visit_app(expr const & e) override {
buffer<expr> args;
expr fn = get_app_args(e, args);
if (m_kind == REC && is_constant(fn) && const_name(fn) == m_rec_name) {
expr new_e = m_ctx.whnf(e);
if (new_e != e)
return visit_app(new_e);
else
return fold_rec(e, args);
}
if (m_kind == BREC && is_constant(fn) && const_name(fn) == get_prod_fst_name() && args.size() >= 3) {
expr rec_fn = get_app_fn(args[1]);
if (is_constant(rec_fn) && const_name(rec_fn) == m_rec_name)
return fold_brec_fst(e, args);
}
if (m_kind == BREC && is_constant(fn) && const_name(fn) == m_prod_rec_name && args.size() >= 5) {
expr rec_fn = get_app_fn(args[4]);
if (is_constant(rec_fn) && const_name(rec_fn) == m_rec_name)
return fold_brec_prod_rec(e, args);
}
return visit_app_default(e, fn, args);
}
};
expr whnf_rec(expr const & e) {
return m_ctx.whnf_pred(e, [&](expr const & c) {
expr const & fn = get_app_fn(c);
return is_constant(fn) && is_rec_building_part(const_name(fn));
});
}
expr get_fn_decl(expr const & fn, type_context::tmp_locals & locals) {
lean_assert(is_constant(fn));
declaration decl = m_env.get(const_name(fn));
if (length(const_levels(fn)) != decl.get_num_univ_params())
throw_ill_formed();
if (!decl.is_definition())
throw exception(sstream() << "unfold tactic failed, '" << const_name(fn) << "' is not a definition");
expr fn_body = instantiate_value_univ_params(decl, const_levels(fn));
while (is_lambda(fn_body)) {
expr local = locals.push_local_from_binding(fn_body);
fn_body = instantiate(binding_body(fn_body), local);
}
return whnf_rec(fn_body);
}
expr unfold(expr const & fn, buffer<expr> args) {
type_context::tmp_locals fn_locals(m_ctx);
expr fn_body = get_fn_decl(fn, fn_locals);
if (args.size() < fn_locals.size()) {
// insufficient args
return unfold_simple(fn, args);
}
name rec_name;
unsigned main_pos = 0;
buffer<unsigned> indices_pos;
buffer<unsigned> rec_arg_pos;
rec_kind k = get_rec_kind(fn_body, fn_locals.as_buffer(), rec_name, indices_pos, main_pos, rec_arg_pos);
if (k == NOREC || main_pos >= args.size()) {
// norecursive definition
return unfold_simple(fn, args);
}
unsigned rest = main_pos >= fn_locals.size() ? main_pos+1 : fn_locals.size();
for (unsigned i = rest; i < args.size(); i++)
rec_arg_pos.push_back(i);
expr new_main = m_ctx.whnf(args[main_pos]);
if (!is_constructor_app(m_env, new_main)) {
// argument is not a constructor or constraints were generated
throw fold_failed();
}
args[main_pos] = new_main;
expr fn_body_abst = m_ctx.abstract_locals(fn_body, fn_locals.as_buffer().size(), fn_locals.as_buffer().data());
expr new_e = instantiate_rev(fn_body_abst, fn_locals.as_buffer().size(), args.data());
new_e = mk_app(new_e, args.size() - fn_locals.as_buffer().size(), args.data() + fn_locals.as_buffer().size());
new_e = whnf_rec(new_e);
expr const new_head = get_app_fn(new_e);
// TODO(Leo): create an option for the following conditions?
if (is_constant(new_head) && inductive::is_elim_rule(m_env, const_name(new_head))) {
// head is a recursor... so the unfold is probably not generating a nice result...
throw fold_failed();
}
return fold_rec_fn(m_ctx, fn, args, k, rec_name, indices_pos, main_pos, rec_arg_pos)(new_e);
}
bool unfold_cnst(expr const & e) {
if (!is_constant(e))
return false;
if (std::find(m_to_unfold.begin(), m_to_unfold.end(), const_name(e)) == m_to_unfold.end())
return false;
m_occ_idx++;
return m_occs.contains(m_occ_idx);
}
virtual expr visit_app(expr const & e) override {
buffer<expr> args;
expr fn = get_app_args(e, args);
bool modified = false;
for (expr & arg : args) {
expr new_arg = visit(arg);
if (arg != new_arg)
modified = true;
arg = new_arg;
}
if (unfold_cnst(fn)) {
try {
return unfold(fn, args);
} catch (fold_failed &) {
if (m_force_unfold)
return unfold_simple(fn, args);
}
}
if (!modified) {
return e;
} else {
return mk_app(fn, args);
}
}
virtual expr visit_constant(expr const & e) override {
if (unfold_cnst(e)) {
if (auto r = unfold_term(m_env, e))
return *r;
}
return e;
}
public:
unfold_rec_fn(type_context & ctx, bool force_unfold, list<name> const & to_unfold, occurrences const & occs):
m_env(ctx.env()),
m_force_unfold(force_unfold),
m_ctx(ctx),
m_to_unfold(to_unfold),
m_occs(occs),
m_occ_idx(0) {}
expr operator()(expr const & e) {
m_occ_idx = 0;
return replace_visitor_aux::operator()(e);
}
};
vm_obj tactic_unfold_expr(vm_obj const & force, vm_obj const & occs, vm_obj const & to_unfold, vm_obj const & e, vm_obj const & s) {
try {
type_context ctx = mk_type_context_for(to_tactic_state(s));
expr r = unfold_rec_fn(ctx, to_bool(force), to_list_name(to_unfold), to_occurrences(occs))(to_expr(e));
return mk_tactic_success(to_obj(r), to_tactic_state(s));
} catch (exception & ex) {
return mk_tactic_exception(ex, to_tactic_state(s));
}
}
vm_obj tactic_unfold_projection_core(vm_obj const & m, vm_obj const & _e, vm_obj const & _s) {
expr const & e = to_expr(_e);
tactic_state const & s = to_tactic_state(_s);
@ -436,8 +37,12 @@ vm_obj tactic_dunfold_expr_core(vm_obj const & m, vm_obj const & _e, vm_obj cons
expr const & fn = get_app_fn(e);
if (!is_constant(fn))
return mk_tactic_exception("dunfold_expr failed, expression is not a constant nor a constant application", s);
expr new_e;
if (has_eqn_lemmas(env, const_name(fn))) {
if (is_projection(s.env(), const_name(fn))) {
type_context ctx = mk_type_context_for(s, to_transparency_mode(m));
if (auto new_e = ctx.reduce_projection(e))
return mk_tactic_success(to_obj(*new_e), s);
return mk_tactic_exception("dunfold_expr failed, failed to unfold projection", s);
} else if (has_eqn_lemmas(env, const_name(fn))) {
type_context ctx = mk_type_context_for(s, to_transparency_mode(m));
buffer<simp_lemma> lemmas;
bool refl_only = true;
@ -465,7 +70,6 @@ vm_obj tactic_dunfold_expr_core(vm_obj const & m, vm_obj const & _e, vm_obj cons
}
void initialize_unfold_tactic() {
DECLARE_VM_BUILTIN(name({"tactic", "unfold_expr_core"}), tactic_unfold_expr);
DECLARE_VM_BUILTIN(name({"tactic", "unfold_projection_core"}), tactic_unfold_projection_core);
DECLARE_VM_BUILTIN(name({"tactic", "dunfold_expr_core"}), tactic_dunfold_expr_core);
}

30
tests/lean/run/dunfold3.lean Normal file
View file

@ -0,0 +1,30 @@
open tactic
def g : nat → nat := λ x, x + 5
example (a b : nat) (p : nat → Prop) (h : p (g (nat.succ (nat.succ a)))) : p (g (a + 2)) :=
begin
unfold g at h,
do { h ← get_local `h >>= infer_type, t ← to_expr `(p (nat.succ (nat.succ a) + 5)), guard (h = t) },
unfold add has_add.add bit0 one nat.add,
unfold g,
do { t ← target, h ← get_local `h >>= infer_type, guard (t = h) },
assumption
end
meta def check_expected (p : pexpr) : tactic unit :=
do t ← target, ex ← to_expr p, guard (t = ex)
example (a b c : nat) (f : nat → nat → nat) (h : false) : f (g a) (g b) = (g c) :=
begin
unfold_occs g [2],
check_expected `(f (g a) (b + 5) = g c),
contradiction
end
example (a b c : nat) (f : nat → nat → nat) (h : false) : f (g a) (g b) = (g c) :=
begin
unfold_occs g [1, 3],
check_expected `(f (a + 5) (g b) = c + 5),
contradiction
end

4
tests/lean/run/unfold_crash.lean
View file

@ -31,10 +31,10 @@ by do
cases_using v2 [`m, `h2, `t2],
trace_state, trace "------",
-- unfold only the first occurrence (i.e., the one of the form (vappend nil nil)
unfold_occs_of [1] `vappend,
dunfold_occs_of [1] `vappend,
trace_state, trace "------",
mk_const `Sorry >>= apply,
-- unfold only the first occurrence (i.e., the one of the form (vappend nil (cons ...))
unfold_occs_of [1] `vappend,
dunfold_occs_of [1] `vappend,
trace_state, trace "------",
repeat $ mk_const `Sorry >>= apply

5
tests/lean/unfold1.lean
View file

@ -1,4 +1,3 @@
exit -- TODO(Leo): enable test again after we add rfl lemma support to type_context
open tactic
meta definition rewriteH (Hname : name) : tactic unit :=
@ -9,10 +8,10 @@ example (l : list nat) : list.append l [] = l :=
by do
get_local `l >>= λ H, induction_core semireducible H `list.rec_on [`h, `t, `iH],
--
unfold [`list.append],
dunfold [`list.append],
trace_state,
trace "------",
reflexivity,
unfold [`list.append],
dunfold [`list.append],
trace_state,
rewriteH `iH

12
tests/lean/unfold1.lean.expected.out
View file

@ -1 +1,11 @@
unfold1.lean:1:0: warning: using 'exit' to interrupt Lean
⊢ list.nil = list.nil
h : ℕ,
t : list ℕ,
iH : list.append t list.nil = t
⊢ list.append (h :: t) list.nil = h :: t
------
h : ℕ,
t : list ℕ,
iH : list.append t list.nil = t
⊢ h :: list.append t list.nil = h :: t

7
tests/lean/unfold_crash.lean
View file

@ -4,7 +4,10 @@ open nat tactic
example (a b : nat) : a = succ b → a = b + 1 :=
by do
H ← intro `H,
try (unfold_at [`nat.succ] H),
unfold [`add], dsimp, unfold [`nat.add],
try (dunfold_at [`nat.succ] H),
dunfold [`add, `has_add.add, `has_one.one, `nat.add, `one],
trace_state,
t ← target,
expected ← to_expr `(a = succ b),
guard (t = expected),
assumption

2
tests/lean/unfold_crash.lean.expected.out
View file

@ -1,3 +1,3 @@
a b : ℕ,
H : a = succ b
⊢ a = add._main b 1
⊢ a = succ b