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feat(frontends/lean): use tactics for solving unassigned metavariables

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-06-29 09:47:25 -07:00
parent 1e39a21823
commit ffa175009b
6 changed files with 96 additions and 28 deletions
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97
src/frontends/lean/elaborator.cpp
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@ -13,6 +13,7 @@ Author: Leonardo de Moura
#include "kernel/abstract.h"
#include "kernel/instantiate.h"
#include "kernel/type_checker.h"
#include "kernel/for_each_fn.h"
#include "kernel/kernel_exception.h"
#include "kernel/error_msgs.h"
#include "kernel/expr_maps.h"
@ -21,6 +22,8 @@ Author: Leonardo de Moura
#include "library/choice.h"
#include "library/explicit.h"
#include "library/unifier.h"
#include "library/tactic/tactic.h"
#include "library/error_handling/error_handling.h"
#include "frontends/lean/parameter.h"
#include "frontends/lean/hint_table.h"
@ -29,16 +32,17 @@ class elaborator {
typedef list<parameter> context;
typedef std::vector<constraint> constraints;
environment m_env;
io_state m_ios;
unifier_plugin m_plugin;
name_generator m_ngen;
hint_table m_hints;
type_checker m_tc;
substitution m_subst;
context m_ctx;
justification m_accumulated; // accumulate justification of eagerly used substitutions
constraints m_constraints;
environment m_env;
io_state m_ios;
unifier_plugin m_plugin;
name_generator m_ngen;
hint_table m_hints;
type_checker m_tc;
substitution m_subst;
context m_ctx;
pos_info_provider * m_pos_provider;
justification m_accumulated; // accumulate justification of eagerly used substitutions
constraints m_constraints;
/**
\brief Auxiliary object for creating backtracking points.
@ -112,11 +116,11 @@ class elaborator {
public:
elaborator(environment const & env, io_state const & ios, name_generator const & ngen,
hint_table const & htable, substitution const & s = substitution(), context const & ctx = context()):
hint_table const & htable, substitution const & s, context const & ctx, pos_info_provider * pp):
m_env(env), m_ios(ios),
m_plugin([](constraint const &, name_generator const &) { return lazy_list<list<constraint>>(); }),
m_ngen(ngen), m_hints(htable), m_tc(env, m_ngen.mk_child(), mk_default_converter(m_env, optional<module_idx>(0))),
m_subst(s), m_ctx(ctx) {
m_subst(s), m_ctx(ctx), m_pos_provider(pp) {
}
expr mk_local(name const & n, expr const & t) {
@ -579,12 +583,64 @@ public:
true, get_unifier_max_steps(m_ios.get_options()));
}
void collect_metavars(expr const & e, buffer<expr> & mvars) {
for_each(e, [&](expr const & e, unsigned) {
if (is_metavar(e)) { mvars.push_back(e); return false; /* do not visit its type */ }
return has_metavar(e);
});
}
optional<tactic> get_tactic_for(expr const & mvar) {
auto it = m_hints.find(mvar.get_tag());
if (it) {
return optional<tactic>(*it);
} else {
// TODO(Leo): m_env tactic hints
return optional<tactic>();
}
}
void display_unsolved_proof_state(expr const & mvar, proof_state const & ps, char const * msg) {
regular out(m_env, m_ios);
display_error_pos(out, m_pos_provider, mvar);
out << " unsolved placeholder, " << msg << "\n" << ps << "\n";
}
expr solve_unassigned_mvars(substitution & subst, expr const & e) {
buffer<expr> mvars;
collect_metavars(e, mvars);
for (auto mvar : mvars) {
mvar = update_mlocal(mvar, subst.instantiate_metavars_wo_jst(mlocal_type(mvar)));
proof_state ps = to_proof_state(m_env, mvar, m_ngen.mk_child(), m_ios.get_options());
if (optional<tactic> t = get_tactic_for(mvar)) {
proof_state_seq seq = (*t)(m_env, m_ios, ps);
if (auto r = seq.pull()) {
if (auto pr = to_proof(r->first)) {
subst = subst.assign(mlocal_name(mvar), *pr, justification());
} else {
display_unsolved_proof_state(mvar, r->first, "unsolved subgoals");
}
} else {
// tactic failed to produce any result
display_unsolved_proof_state(mvar, ps, "tactic failed");
}
}
}
return subst.instantiate_metavars_wo_jst(e);
}
/** \brief Apply substitution and solve remaining metavariables using tactics. */
expr apply(substitution & s, expr const & e) {
expr r = s.instantiate_metavars_wo_jst(e);
return solve_unassigned_mvars(s, r);
}
expr operator()(expr const & e) {
expr r = visit(e);
auto p = solve().pull();
lean_assert(p);
substitution s = p->first;
return s.instantiate_metavars_wo_jst(r);
return apply(s, r);
}
std::pair<expr, expr> operator()(expr const & t, expr const & v, name const & n) {
@ -606,24 +662,23 @@ public:
auto p = solve().pull();
lean_assert(p);
substitution s = p->first;
return mk_pair(s.instantiate_metavars_wo_jst(r_t),
s.instantiate_metavars_wo_jst(r_v));
return mk_pair(apply(s, r_t), apply(s, r_v));
}
};
static name g_tmp_prefix = name::mk_internal_unique_name();
expr elaborate(environment const & env, io_state const & ios, expr const & e, name_generator const & ngen,
hint_table const & htable, substitution const & s, list<parameter> const & ctx) {
return elaborator(env, ios, ngen, htable, s, ctx)(e);
hint_table const & htable, substitution const & s, list<parameter> const & ctx, pos_info_provider * pp) {
return elaborator(env, ios, ngen, htable, s, ctx, pp)(e);
}
expr elaborate(environment const & env, io_state const & ios, expr const & e, hint_table const & htable) {
return elaborate(env, ios, e, name_generator(g_tmp_prefix), htable, substitution(), list<parameter>());
expr elaborate(environment const & env, io_state const & ios, expr const & e, hint_table const & htable, pos_info_provider * pp) {
return elaborate(env, ios, e, name_generator(g_tmp_prefix), htable, substitution(), list<parameter>(), pp);
}
std::pair<expr, expr> elaborate(environment const & env, io_state const & ios, name const & n, expr const & t, expr const & v,
hint_table const & htable) {
return elaborator(env, ios, name_generator(g_tmp_prefix), htable)(t, v, n);
hint_table const & htable, pos_info_provider * pp) {
return elaborator(env, ios, name_generator(g_tmp_prefix), htable, substitution(), list<parameter>(), pp)(t, v, n);
}
}

8
src/frontends/lean/elaborator.h
View file

@ -14,8 +14,10 @@ Author: Leonardo de Moura
namespace lean {
expr elaborate(environment const & env, io_state const & ios, expr const & e, name_generator const & ngen,
hint_table const & htable = hint_table(), substitution const & s = substitution(), list<parameter> const & ctx = list<parameter>());
expr elaborate(environment const & env, io_state const & ios, expr const & e, hint_table const & htable = hint_table());
hint_table const & htable = hint_table(), substitution const & s = substitution(),
list<parameter> const & ctx = list<parameter>(), pos_info_provider * pp = nullptr);
expr elaborate(environment const & env, io_state const & ios, expr const & e, hint_table const & htable = hint_table(),
pos_info_provider * pp = nullptr);
std::pair<expr, expr> elaborate(environment const & env, io_state const & ios, name const & n, expr const & t, expr const & v,
hint_table const & htable = hint_table());
hint_table const & htable = hint_table(), pos_info_provider * pp = nullptr);
}

9
src/frontends/lean/parser.cpp
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@ -546,15 +546,18 @@ expr parser::mk_Type() {
}
expr parser::elaborate(expr const & e) {
return ::lean::elaborate(m_env, m_ios, e, m_hints);
parser_pos_provider pp(m_pos_table, get_stream_name(), m_last_cmd_pos);
return ::lean::elaborate(m_env, m_ios, e, m_hints, &pp);
}
expr parser::elaborate(environment const & env, expr const & e) {
return ::lean::elaborate(env, m_ios, e, m_hints);
parser_pos_provider pp(m_pos_table, get_stream_name(), m_last_cmd_pos);
return ::lean::elaborate(env, m_ios, e, m_hints, &pp);
}
std::pair<expr, expr> parser::elaborate(name const & n, expr const & t, expr const & v) {
return ::lean::elaborate(m_env, m_ios, n, t, v, m_hints);
parser_pos_provider pp(m_pos_table, get_stream_name(), m_last_cmd_pos);
return ::lean::elaborate(m_env, m_ios, n, t, v, m_hints, &pp);
}
/** \brief Parse <tt>ID ':' expr</tt>, where the expression represents the type of the identifier. */

1
src/library/error_handling/error_handling.cpp
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@ -151,4 +151,3 @@ void display_error(io_state_stream const & ios, pos_info_provider const * p, exc
}
}
}

5
src/library/error_handling/error_handling.h
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@ -10,6 +10,11 @@ Author: Leonardo de Moura
#include "library/io_state_stream.h"
namespace lean {
/**
\brief Display position information associated with \c e (IF avaiable).
If it is not available, it just displays "error:"
*/
void display_error_pos(io_state_stream const & ios, pos_info_provider const * p, expr const & e);
/**
\brief Display exception in the regular stream of \c ios, using the configuration options and formatter from \c ios.
Exceptions that contain expressions use the given \c pos_info_provider (if available) to retrieve line number information.

4
tests/lean/run/tactic1.lean Normal file
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@ -0,0 +1,4 @@
import logic
theorem tst {A B : Bool} (H1 : A) (H2 : B) : A
:= by assumption