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feat(library/unifier): add support for choice constraint

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-06-22 17:21:24 -07:00
parent 611f29a954
commit 228f51dcfa
2 changed files with 52 additions and 8 deletions
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4
src/kernel/constraint.h
View file

@ -38,7 +38,7 @@ typedef std::tuple<expr, justification, constraints> choice_fn_result;
/**
\brief A choice_fn is used to enumerate the possible solutions for a metavariable.
The input arguments are:
- an inferred type (if available)
- an inferred type
- substitution map (metavar -> value)
- name generator
@ -49,7 +49,7 @@ typedef std::tuple<expr, justification, constraints> choice_fn_result;
One application of choice constraints is overloaded notation.
*/
typedef std::function<lazy_list<choice_fn_result>(optional<expr> const &, substitution const &, name_generator const &)> choice_fn;
typedef std::function<lazy_list<choice_fn_result>(expr const &, substitution const &, name_generator const &)> choice_fn;
struct constraint_cell;
class constraint {

56
src/library/unifier.cpp
View file

@ -220,6 +220,15 @@ struct unifier_fn {
virtual bool next(unifier_fn & u) { return u.next_plugin_case_split(*this); }
};
struct choice_case_split : public case_split {
expr m_mvar;
justification m_jst;
lazy_list<choice_fn_result> m_tail;
choice_case_split(unifier_fn & u, expr const & mvar, justification const & j, lazy_list<choice_fn_result> const & tail):
case_split(u), m_mvar(mvar), m_jst(j), m_tail(tail) {}
virtual bool next(unifier_fn & u) { return u.next_choice_case_split(*this); }
};
case_split_stack m_case_splits;
optional<justification> m_conflict;
@ -502,12 +511,6 @@ struct unifier_fn {
return optional<substitution>();
}
bool process_choice_constraint(constraint const & c) {
lean_assert(is_choice_cnstr(c));
// TODO(Leo)
return true;
}
// Process constraints in \c cs, and append justification \c j to them.
bool process_constraints(constraints const & cs, justification const & j) {
for (constraint const & c : cs)
@ -515,6 +518,47 @@ struct unifier_fn {
return !in_conflict();
}
bool process_choice_result(expr const & m, choice_fn_result const & r, justification j) {
j = mk_composite1(j, std::get<1>(r));
return
process_constraint(mk_eq_cnstr(m, std::get<0>(r), j)) &&
process_constraints(std::get<2>(r), j);
}
bool next_choice_case_split(choice_case_split & cs) {
auto r = cs.m_tail.pull();
if (r) {
cs.restore_state(*this);
lean_assert(!in_conflict());
cs.m_tail = r->second;
justification a = mk_assumption_justification(cs.m_assumption_idx);
return process_choice_result(cs.m_mvar, r->first, mk_composite1(cs.m_jst, a));
} else {
// update conflict
update_conflict(mk_composite1(*m_conflict, cs.m_failed_justifications));
return false;
}
}
bool process_choice_constraint(constraint const & c) {
lean_assert(is_choice_cnstr(c));
expr const & m = cnstr_mvar(c);
choice_fn const & fn = cnstr_choice_fn(c);
lean_assert(is_meta(m));
auto m_type_jst = m_subst.instantiate_metavars(m_tc.infer(m), nullptr, nullptr);
auto rlist = fn(m_type_jst.first, m_subst, m_ngen.mk_child());
auto r = rlist.pull();
justification j = mk_composite1(c.get_justification(), m_type_jst.second);
if (r) {
justification a = mk_assumption_justification(m_next_assumption_idx);
add_case_split(std::unique_ptr<case_split>(new choice_case_split(*this, m, m_type_jst.second, r->second)));
return process_choice_result(m, r->first, mk_composite1(j, a));
} else {
set_conflict(j);
return false;
}
}
bool next_plugin_case_split(plugin_case_split & cs) {
auto r = cs.m_tail.pull();
if (r) {