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Add basic support for metavariables at is_convertible. Swap is_convertible arguments to make it more intuitive.

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-09-17 07:15:47 -07:00
parent 789d90117a
commit 30b19c314a
8 changed files with 68 additions and 30 deletions
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6
src/frontends/lean/elaborator.cpp
View file

@ -283,7 +283,7 @@ class elaborator::imp {
expr expected = abst_domain(f_t);
expr given = types[i];
if (!has_metavar(expected) && !has_metavar(given)) {
if (is_convertible(expected, given, ctx)) {
if (is_convertible(given, expected, ctx)) {
// compatible
} else if (m_frontend.get_coercion(given, expected, ctx)) {
// compatible if using coercion
@ -403,7 +403,7 @@ class elaborator::imp {
info_ref r = mk_app_mismatch_info(e, ctx, args.size(), args.data(), types.data());
m_constraints.push_back(constraint(expected, given, ctx, r));
} else {
if (!is_convertible(expected, given, ctx)) {
if (!is_convertible(given, expected, ctx)) {
expr coercion = m_frontend.get_coercion(given, expected, ctx);
if (coercion) {
modified = true;
@ -459,7 +459,7 @@ class elaborator::imp {
info_ref r = mk_expected_type_info(let_value(e), v_p.first, expected, given, ctx);
m_constraints.push_back(constraint(expected, given, ctx, r));
} else {
if (!is_convertible(expected, given, ctx)) {
if (!is_convertible(given, expected, ctx)) {
expr coercion = m_frontend.get_coercion(given, expected, ctx);
if (coercion) {
v_p.first = mk_app(coercion, v_p.first);

2
src/kernel/environment.cpp
View file

@ -224,7 +224,7 @@ struct environment::imp {
void check_type(name const & n, expr const & t, expr const & v, environment const & env) {
m_type_checker.infer_universe(t);
expr v_t = m_type_checker.infer_type(v);
if (!m_type_checker.is_convertible(t, v_t))
if (!m_type_checker.is_convertible(v_t, t))
throw def_type_mismatch_exception(env, n, t, v, v_t);
}

4
src/kernel/metavar.cpp
View file

@ -107,6 +107,9 @@ void metavar_env::assign(expr const & m, expr const & t) {
}
expr instantiate_metavars(expr const & e, metavar_env const & env) {
if (!has_metavar(e)) {
return e;
} else {
auto f = [=](expr const & m, unsigned offset) -> expr {
if (is_metavar(m) && env.contains(m)) {
expr s = env.get_subst(m);
@ -116,6 +119,7 @@ expr instantiate_metavars(expr const & e, metavar_env const & env) {
}
};
return replace_fn<decltype(f)>(f)(e);
}
}
meta_ctx add_lift(meta_ctx const & ctx, unsigned s, unsigned n) {

7
src/kernel/metavar.h
View file

@ -16,6 +16,7 @@ namespace lean {
It store two kinds of problems:
1. <tt>ctx |- lhs == rhs</tt>
2. <tt>ctx |- typeof(n) == t</tt>
3. <tt>ctx |- t1 is_convertible_to t2</tt>
*/
class unification_problems {
public:
@ -28,6 +29,12 @@ public:
\brief Add a new unification problem of the form <tt>ctx |- typeof(n) == t</tt>
*/
virtual void add_type_of_eq(context const & ctx, expr const & n, expr const & t) = 0;
/**
\brief Add a new problem of the form <tt>ctx |- t1 is_convertible_to t2</tt>
\remark <tt>ctx |- t1 == t2</tt> implies <tt>ctx |- t1 is_convertible_to t2</tt>
*/
virtual void add_is_convertible(context const & ctx, expr const & t1, expr const & t2) = 0;
};
/**

45
src/kernel/normalizer.cpp
View file

@ -292,12 +292,12 @@ class normalizer::imp {
return r;
}
bool is_convertible_core(expr const & expected, expr const & given) {
if (expected == given) {
bool is_convertible_core(expr const & given, expr const & expected) {
if (given == expected) {
return true;
} else {
expr const * e = &expected;
expr const * g = &given;
expr const * e = &expected;
while (true) {
if (is_type(*e) && is_type(*g)) {
if (m_env.is_ge(ty_level(*e), ty_level(*g)))
@ -308,8 +308,8 @@ class normalizer::imp {
return true;
if (is_pi(*e) && is_pi(*g) && abst_domain(*e) == abst_domain(*g)) {
e = &abst_body(*e);
g = &abst_body(*g);
e = &abst_body(*e);
} else {
return false;
}
@ -355,14 +355,31 @@ public:
return reify(normalize(e, value_stack(), k), k);
}
bool is_convertible(expr const & expected, expr const & given, context const & ctx) {
if (is_convertible_core(expected, given))
bool is_convertible(expr const & given, expr const & expected, context const & ctx,
metavar_env * menv, unification_problems * up) {
if (is_convertible_core(given, expected))
return true;
expr new_given = given;
expr new_expected = expected;
if (has_metavar(new_given) || has_metavar(new_expected)) {
expr new_given = instantiate_metavars(new_given, *menv);
expr new_expected = instantiate_metavars(new_expected, *menv);
if (is_convertible_core(new_given, new_expected))
return true;
if (has_metavar(new_given) || has_metavar(new_expected)) {
// Very conservative approach, just postpone the problem.
// We may also try to normalize new_given and new_expected even if
// they contain metavariables.
up->add_is_convertible(ctx, new_given, new_expected);
return true;
}
}
set_menv(menv);
set_ctx(ctx);
unsigned k = m_ctx.size();
expr e_n = reify(normalize(expected, value_stack(), k), k);
expr g_n = reify(normalize(given, value_stack(), k), k);
return is_convertible_core(e_n, g_n);
new_given = reify(normalize(new_given, value_stack(), k), k);
new_expected = reify(normalize(new_expected, value_stack(), k), k);
return is_convertible_core(new_given, new_expected);
}
void clear() { m_ctx = context(); m_cache.clear(); m_menv = nullptr; m_menv_timestamp = 0; }
@ -374,15 +391,19 @@ normalizer::normalizer(environment const & env):normalizer(env, std::numeric_lim
normalizer::normalizer(environment const & env, options const & opts):normalizer(env, get_normalizer_max_depth(opts)) {}
normalizer::~normalizer() {}
expr normalizer::operator()(expr const & e, context const & ctx, metavar_env const * menv) { return (*m_ptr)(e, ctx, menv); }
bool normalizer::is_convertible(expr const & t1, expr const & t2, context const & ctx) { return m_ptr->is_convertible(t1, t2, ctx); }
bool normalizer::is_convertible(expr const & t1, expr const & t2, context const & ctx,
metavar_env * menv, unification_problems * up) {
return m_ptr->is_convertible(t1, t2, ctx, menv, up);
}
void normalizer::clear() { m_ptr->clear(); }
void normalizer::set_interrupt(bool flag) { m_ptr->set_interrupt(flag); }
expr normalize(expr const & e, environment const & env, context const & ctx, metavar_env const * menv) {
return normalizer(env)(e, ctx, menv);
}
bool is_convertible(expr const & expected, expr const & given, environment const & env, context const & ctx) {
return normalizer(env).is_convertible(expected, given, ctx);
bool is_convertible(expr const & given, expr const & expected, environment const & env, context const & ctx,
metavar_env * menv, unification_problems * up) {
return normalizer(env).is_convertible(given, expected, ctx, menv, up);
}
}

7
src/kernel/normalizer.h
View file

@ -14,6 +14,7 @@ namespace lean {
class environment;
class options;
class metavar_env;
class unification_problems;
/** \brief Functional object for normalizing expressions */
class normalizer {
class imp;
@ -25,7 +26,8 @@ public:
~normalizer();
expr operator()(expr const & e, context const & ctx = context(), metavar_env const * menv = nullptr);
bool is_convertible(expr const & t1, expr const & t2, context const & ctx = context());
bool is_convertible(expr const & t1, expr const & t2, context const & ctx = context(),
metavar_env * menv = nullptr, unification_problems * up = nullptr);
void clear();
@ -35,5 +37,6 @@ public:
};
/** \brief Normalize \c e using the environment \c env and context \c ctx */
expr normalize(expr const & e, environment const & env, context const & ctx = context(), metavar_env const * menv = nullptr);
bool is_convertible(expr const & t1, expr const & t2, environment const & env, context const & ctx = context());
bool is_convertible(expr const & t1, expr const & t2, environment const & env, context const & ctx = context(),
metavar_env * menv = nullptr, unification_problems * up = nullptr);
}

4
src/kernel/type_checker.cpp
View file

@ -94,7 +94,7 @@ public:
while (true) {
expr const & c = arg(e, i);
expr const & c_t = arg_types[i];
if (!m_normalizer.is_convertible(abst_domain(f_t), c_t, ctx))
if (!m_normalizer.is_convertible(c_t, abst_domain(f_t), ctx))
throw app_type_mismatch_exception(m_env, ctx, e, arg_types.size(), arg_types.data());
if (closed(abst_body(f_t)))
f_t = abst_body(f_t);
@ -140,7 +140,7 @@ public:
expr lt = infer_type(let_value(e), ctx);
if (let_type(e)) {
infer_universe(let_type(e), ctx); // check if it is really a type
if (!m_normalizer.is_convertible(let_type(e), lt, ctx))
if (!m_normalizer.is_convertible(lt, let_type(e), ctx))
throw def_type_mismatch_exception(m_env, ctx, let_name(e), let_type(e), let_value(e), lt);
}
{

3
src/tests/kernel/metavar.cpp
View file

@ -20,13 +20,16 @@ using namespace lean;
class unification_problems_dbg : public unification_problems {
std::vector<std::pair<expr, expr>> m_eqs;
std::vector<std::pair<expr, expr>> m_type_of_eqs;
std::vector<std::pair<expr, expr>> m_is_convertible_cnstrs;
public:
unification_problems_dbg() {}
virtual ~unification_problems_dbg() {}
virtual void add_eq(context const &, expr const & lhs, expr const & rhs) { m_eqs.push_back(mk_pair(lhs, rhs)); }
virtual void add_type_of_eq(context const &, expr const & n, expr const & t) { m_type_of_eqs.push_back(mk_pair(n, t)); }
virtual void add_is_convertible(context const &, expr const & t1, expr const & t2) { m_is_convertible_cnstrs.push_back(mk_pair(t1, t2)); }
std::vector<std::pair<expr, expr>> const & eqs() const { return m_eqs; }
std::vector<std::pair<expr, expr>> const & type_of_eqs() const { return m_type_of_eqs; }
std::vector<std::pair<expr, expr>> const & is_convertible_cnstrs() const { return m_is_convertible_cnstrs; }
};
static void tst1() {