refactor(kernel): justification objects

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-02-20 17:19:03 -08:00
parent 50300126a5
commit 2a73389ed3
6 changed files with 314 additions and 118 deletions

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@ -2,10 +2,10 @@ add_library(kernel level.cpp diff_cnstrs.cpp expr.cpp expr_eq_fn.cpp
for_each_fn.cpp occurs.cpp replace_fn.cpp free_vars.cpp abstract.cpp
instantiate.cpp context.cpp formatter.cpp max_sharing.cpp kernel_exception.cpp
object.cpp environment.cpp replace_visitor.cpp io_state.cpp
normalizer.cpp
# type_checker.cpp kernel.cpp
# justification.cpp unification_constraint.cpp
# type_checker_justification.cpp pos_info_provider.cpp
normalizer.cpp justification.cpp pos_info_provider.cpp
# type_checker.cpp
# unification_constraint.cpp
# type_checker_justification.cpp
)
target_link_libraries(kernel ${LEAN_LIBS})

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@ -6,76 +6,232 @@ Author: Leonardo de Moura
*/
#include <vector>
#include "util/buffer.h"
#include "util/int64.h"
#include "kernel/justification.h"
#include "kernel/metavar.h"
namespace lean {
void justification_cell::add_pos_info(format & r, optional<expr> const & e, pos_info_provider const * p) {
format to_pos(optional<expr> const & e, pos_info_provider const * p) {
if (!p || !e)
return;
return format();
format f = p->pp(*e);
if (!f)
return;
r += f;
r += space();
return format();
return f + space();
}
format justification_cell::pp(formatter const & fmt, options const & opts, pos_info_provider const * p, bool display_children,
optional<metavar_env> const & menv) const {
format r;
add_pos_info(r, get_main_expr(), p);
r += pp_header(fmt, opts, menv);
if (display_children) {
buffer<justification_cell *> children;
get_children(children);
unsigned indent = get_pp_indent(opts);
for (justification_cell * child : children) {
r += nest(indent, compose(line(), child->pp(fmt, opts, p, display_children, menv)));
}
typedef uint64 approx_set;
static approx_set mk_empty_set() { return 0; }
static approx_set mk_union(approx_set s1, approx_set s2) { return s1 | s2; }
static approx_set mk_intersection(approx_set s1, approx_set s2) { return s1 & s2; }
static approx_set mk_singleton(unsigned i) { return static_cast<uint64>(1) << (i % 64); }
static approx_set may_contain(approx_set s, unsigned i) { return mk_intersection(s, mk_singleton(i)) != 0ull; }
enum class justification_kind { Asserted, Composite, ExtComposite, Assumption, ExtAssumption };
approx_set get_approx_assumption_set(justification const & j);
struct justification_cell {
MK_LEAN_RC();
justification_kind m_kind;
void dealloc();
justification_cell(justification_kind k):m_rc(0), m_kind(k) {}
bool is_asserted() const { return m_kind == justification_kind::Asserted; }
bool is_assumption() const { return m_kind == justification_kind::Assumption || m_kind == justification_kind::ExtAssumption; }
bool is_composite() const { return m_kind == justification_kind::Composite || m_kind == justification_kind::ExtComposite; }
bool is_ext_assumption() const { return m_kind == justification_kind::ExtAssumption; }
bool is_ext_composite() const { return m_kind == justification_kind::ExtComposite; }
};
struct asserted_cell : public justification_cell {
pp_jst_fn m_fn;
optional<expr> m_expr;
asserted_cell(pp_jst_fn const & fn, optional<expr> const & e):
justification_cell(justification_kind::Asserted),
m_fn(fn), m_expr(e) {}
};
struct composite_cell : public justification_cell {
approx_set m_assumption_set; // approximated set of assumptions contained in child1 and child2
justification m_child[2];
composite_cell(justification_kind k, justification const & j1, justification const & j2):
justification_cell(k) {
m_child[0] = j1;
m_child[1] = j2;
m_assumption_set = mk_union(get_approx_assumption_set(j1), get_approx_assumption_set(j2));
}
return r;
composite_cell(justification const & j1, justification const & j2):
composite_cell(justification_kind::Composite, j1, j2) {}
};
struct ext_composite_cell : public composite_cell {
pp_jst_fn m_fn;
optional<expr> m_expr;
ext_composite_cell(justification const & j1, justification const & j2, pp_jst_fn const & fn, optional<expr> const & e):
composite_cell(justification_kind::ExtComposite, j1, j2),
m_fn(fn),
m_expr(e) {}
};
struct assumption_cell : public justification_cell {
unsigned m_idx;
assumption_cell(justification_kind k, unsigned idx):
justification_cell(k), m_idx(idx) {}
assumption_cell(unsigned idx):
assumption_cell(justification_kind::Assumption, idx) {}
};
struct ext_assumption_cell : public assumption_cell {
pp_jst_fn m_fn;
optional<expr> m_expr;
ext_assumption_cell(unsigned idx, pp_jst_fn const & fn, optional<expr> const & e):
assumption_cell(justification_kind::ExtAssumption, idx),
m_fn(fn),
m_expr(e) {}
};
asserted_cell * to_asserted(justification_cell * j) { lean_assert(j && j->is_asserted()); return static_cast<asserted_cell*>(j); }
assumption_cell * to_assumption(justification_cell * j) { lean_assert(j && j->is_assumption()); return static_cast<assumption_cell*>(j); }
ext_assumption_cell * to_ext_assumption(justification_cell * j) { lean_assert(j && j->is_ext_assumption()); return static_cast<ext_assumption_cell*>(j); }
composite_cell * to_composite(justification_cell * j) { lean_assert(j && j->is_composite()); return static_cast<composite_cell*>(j); }
ext_composite_cell * to_ext_composite(justification_cell * j) { lean_assert(j && j->is_composite()); return static_cast<ext_composite_cell*>(j); }
approx_set get_approx_assumption_set(justification const & j) {
justification_cell * it = j.raw();
if (!it)
return mk_empty_set();
switch (it->m_kind) {
case justification_kind::Asserted:
return mk_empty_set();
case justification_kind::Assumption: case justification_kind::ExtAssumption:
return mk_singleton(to_assumption(it)->m_idx);
case justification_kind::Composite: case justification_kind::ExtComposite:
return to_composite(it)->m_assumption_set;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
bool justification::has_children() const {
buffer<justification_cell *> r;
get_children(r);
return !r.empty();
}
format justification::pp(formatter const & fmt, options const & opts, pos_info_provider const * p,
bool display_children, optional<metavar_env> const & menv) const {
lean_assert(m_ptr);
return m_ptr->pp(fmt, opts, p, display_children, menv);
}
format justification::pp(formatter const & fmt, options const & opts, pos_info_provider const * p, bool display_children) const {
lean_assert(m_ptr);
return m_ptr->pp(fmt, opts, p, display_children, optional<metavar_env>());
void justification_cell::dealloc() {
switch (m_kind) {
case justification_kind::Asserted: delete to_asserted(this); break;
case justification_kind::Assumption: delete to_assumption(this); break;
case justification_kind::ExtAssumption: delete to_ext_assumption(this); break;
case justification_kind::Composite: delete to_composite(this); break;
case justification_kind::ExtComposite: delete to_ext_composite(this); break;
}
}
assumption_justification::assumption_justification(unsigned idx):m_idx(idx) {}
void assumption_justification::get_children(buffer<justification_cell*> &) const {}
optional<expr> assumption_justification::get_main_expr() const { return none_expr(); }
format assumption_justification::pp_header(formatter const &, options const &, optional<metavar_env> const &) const {
return format{format("Assumption"), space(), format(m_idx)};
}
bool depends_on(justification const & t, justification const & d) {
bool depends_on(justification const & j, unsigned i) {
if (!may_contain(get_approx_assumption_set(j), i))
return false;
buffer<justification_cell *> todo;
buffer<justification_cell *> children;
todo.push_back(t.raw());
todo.push_back(j.raw());
while (!todo.empty()) {
justification_cell * curr = todo.back();
todo.pop_back();
if (curr == d.raw()) {
return true;
} else {
children.clear();
curr->get_children(children);
for (justification_cell * child : children) {
todo.push_back(child);
switch (curr->m_kind) {
case justification_kind::Asserted:
break;
case justification_kind::Assumption: case justification_kind::ExtAssumption:
if (to_assumption(curr)->m_idx == i)
return true;
break;
case justification_kind::Composite: case justification_kind::ExtComposite:
for (unsigned i = 0; i < 2; i++) {
justification c = to_composite(curr)->m_child[i];
if (may_contain(get_approx_assumption_set(c), i))
todo.push_back(c.raw());
}
}
}
return false;
}
justification const & composite_child1(justification const & j) {
lean_assert(j.is_composite());
return to_composite(j.raw())->m_child[0];
}
justification const & composite_child2(justification const & j) {
lean_assert(j.is_composite());
return to_composite(j.raw())->m_child[0];
}
unsigned assumption_idx(justification const & j) {
lean_assert(j.is_assumption());
return to_assumption(j.raw())->m_idx;
}
justification::justification():m_ptr(nullptr) {}
justification::justification(justification_cell * ptr):m_ptr(ptr) { if (m_ptr) m_ptr->inc_ref(); }
justification::justification(justification const & s):m_ptr(s.m_ptr) { if (m_ptr) m_ptr->inc_ref(); }
justification::justification(justification && s):m_ptr(s.m_ptr) { s.m_ptr = nullptr; }
justification::~justification() { if (m_ptr) m_ptr->dec_ref(); }
bool justification::is_none() const { return m_ptr == nullptr; }
bool justification::is_asserted() const { return m_ptr && m_ptr->is_asserted(); }
bool justification::is_assumption() const { return m_ptr && m_ptr->is_assumption(); }
bool justification::is_composite() const { return m_ptr && m_ptr->is_composite(); }
justification & justification::operator=(justification const & s) { LEAN_COPY_REF(s); }
justification & justification::operator=(justification && s) { LEAN_MOVE_REF(s); }
optional<expr> justification::get_main_expr() const {
justification_cell * it = m_ptr;
while (true) {
if (!it)
return none_expr();
switch (it->m_kind) {
case justification_kind::Asserted:
return to_asserted(it)->m_expr;
case justification_kind::ExtAssumption:
return to_ext_assumption(it)->m_expr;
case justification_kind::ExtComposite:
return to_ext_composite(it)->m_expr;
case justification_kind::Assumption:
return none_expr();
case justification_kind::Composite:
it = to_composite(it)->m_child[0].raw();
break;
}
}
}
format justification::pp(formatter const & fmt, options const & opts, pos_info_provider const * p, substitution const & s) {
justification_cell * it = m_ptr;
while (true) {
if (!it)
return format();
switch (it->m_kind) {
case justification_kind::Asserted:
return to_asserted(it)->m_fn(fmt, opts, p, s);
case justification_kind::ExtAssumption:
return to_ext_assumption(it)->m_fn(fmt, opts, p, s);
case justification_kind::ExtComposite:
return to_ext_composite(it)->m_fn(fmt, opts, p, s);
case justification_kind::Assumption:
return format(format("Assumption "), format(to_assumption(it)->m_idx));
case justification_kind::Composite:
it = to_composite(it)->m_child[0].raw();
break;
}
}
}
justification mk_composite(justification const & j1, justification const & j2, pp_jst_fn const & fn, optional<expr> const & s) {
return justification(new ext_composite_cell(j1, j2, fn, s));
}
justification mk_composite1(justification const & j1, justification const & j2) {
return justification(new composite_cell(j1, j2));
}
justification mk_assumption_justification(unsigned idx, pp_jst_fn const & fn, optional<expr> const & s) {
return justification(new ext_assumption_cell(idx, fn, s));
}
justification mk_assumption_justification(unsigned idx) {
return justification(new assumption_cell(idx));
}
justification mk_justification(pp_jst_fn const & fn, optional<expr> const & s) {
return justification(new asserted_cell(fn, s));
}
justification mk_justification(pp_jst_sfn const & fn, optional<expr> const & s) {
return mk_justification([=](formatter const & fmt, options const & opts, pos_info_provider const * p, substitution const & subst) {
return compose(to_pos(s, p), fn(fmt, opts, subst));
}, s);
}
}

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@ -15,87 +15,121 @@ Author: Leonardo de Moura
#include "kernel/pos_info_provider.h"
namespace lean {
class metavar_env;
class justification;
/**
\brief Base class used to represent justification objects.
These objects are used to justification the execution of different engines in Lean.
The justifications may help users understanding why something did not work.
The justifications are particularly important for the elaborator.
*/
class justification_cell {
MK_LEAN_RC();
void dealloc() { delete this; }
protected:
static void add_pos_info(format & r, optional<expr> const & e, pos_info_provider const * p);
public:
justification_cell():m_rc(0) {}
virtual ~justification_cell() {}
virtual format pp_header(formatter const & fmt, options const & opts, optional<metavar_env> const & menv) const = 0;
virtual format pp(formatter const & fmt, options const & opts, pos_info_provider const * p,
bool display_children, optional<metavar_env> const & menv) const;
virtual void get_children(buffer<justification_cell*> & r) const = 0;
virtual optional<expr> get_main_expr() const { return none_expr(); }
bool is_shared() const { return get_rc() > 1; }
};
class substitution;
struct justification_cell;
/**
\brief Base class for justification objects used to justify case-splits.
\brief When a set of constraints cannot be solved, we must print some "error" message to the user.
The pp_jst_fn is a generic funciton that produces these messages. We can associate these functions
to justification objects.
*/
class assumption_justification : public justification_cell {
unsigned m_idx;
public:
assumption_justification(unsigned idx);
virtual void get_children(buffer<justification_cell*> &) const;
virtual optional<expr> get_main_expr() const;
virtual format pp_header(formatter const &, options const &, optional<metavar_env> const & menv) const;
};
typedef std::function<format(formatter const &, options const &, pos_info_provider const *, substitution const &)> pp_jst_fn;
/**
\brief Smart pointer for justification_cell's
\brief Objects used to justify unification (and level) constraints and metavariable assignments.
There are 4 basic kinds of justification:
- None: the null justification.
- Asserted: a justification produced by the type checker.
- Assumption: for case-splits inside the elaborator and other constraint solvers.
- Composite: the combination of two other justification objects.
A composite justification is used, for example, to justify a constraint produced by
replacing a metavariable ?M by its assignment in a constraint C.
*/
class justification {
justification_cell * m_ptr;
justification(justification_cell * ptr);
public:
justification():m_ptr(nullptr) {}
justification(justification_cell * ptr):m_ptr(ptr) { if (m_ptr) m_ptr->inc_ref(); }
justification(justification const & s):m_ptr(s.m_ptr) { if (m_ptr) m_ptr->inc_ref(); }
justification(justification && s):m_ptr(s.m_ptr) { s.m_ptr = nullptr; }
~justification() { if (m_ptr) m_ptr->dec_ref(); }
explicit operator bool() const { return m_ptr != nullptr; }
justification_cell * raw() const { return m_ptr; }
justification();
justification(justification const & s);
justification(justification && s);
~justification();
friend void swap(justification & a, justification & b) { std::swap(a.m_ptr, b.m_ptr); }
justification & operator=(justification const & s) { LEAN_COPY_REF(s); }
justification & operator=(justification && s) { LEAN_MOVE_REF(s); }
format pp(formatter const & fmt, options const & opts, pos_info_provider const * p,
bool display_children, optional<metavar_env> const & menv) const;
format pp(formatter const & fmt, options const & opts, pos_info_provider const * p = nullptr, bool display_children = true) const;
optional<expr> get_main_expr() const { return m_ptr ? m_ptr->get_main_expr() : none_expr(); }
void get_children(buffer<justification_cell*> & r) const { if (m_ptr) m_ptr->get_children(r); }
bool has_children() const;
bool is_none() const;
bool is_asserted() const;
bool is_assumption() const;
bool is_composite() const;
justification_cell * raw() const { return m_ptr; }
justification & operator=(justification const & s);
justification & operator=(justification && s);
/**
\brief Convert this justification into a format object. This method is usually used to report
"error" messages to users.
*/
format pp(formatter const & fmt, options const & opts, pos_info_provider const * p, substitution const & s);
/**
\brief Return an expression associated with the justification object.
*/
optional<expr> get_main_expr() const;
friend justification mk_composite(justification const & j1, justification const & j2, pp_jst_fn const & fn, optional<expr> const & s);
friend justification mk_composite1(justification const & j1, justification const & j2);
friend justification mk_assumption_justification(unsigned idx, pp_jst_fn const & fn, optional<expr> const & s);
friend justification mk_assumption_justification(unsigned idx);
friend justification mk_justification(pp_jst_fn const & fn, optional<expr> const & s);
};
inline justification mk_assumption_justification(unsigned idx) { return justification(new assumption_justification(idx)); }
/**
\brief Simplifer version of pp_jst_fn
*/
typedef std::function<format(formatter const &, options const &, substitution const &)> pp_jst_sfn;
/** \brief Return a format object containing position information for the given expression (if available) */
format to_pos(optional<expr> const & e, pos_info_provider const * p);
/**
\brief Return true iff \c t depends on \c d.
That is \c t is a descendant of \c d.
\brief Combine the two given justifications into a new justification object, and use
the given function to convert the justification into a format object.
*/
bool depends_on(justification const & t, justification const & d);
justification mk_composite(justification const & j1, justification const & j2, pp_jst_fn const & fn, optional<expr> const & s);
/**
\brief Similar to \c mk_composite, but uses \c j1.pp to convert the
resulting justification into a format object.
*/
justification mk_composite1(justification const & j1, justification const & j2);
/**
\brief Alias for \c mk_composite1
*/
justification mk_substitution_justification(justification const & j1, justification const & j2);
/**
\brief Create a "case-split" justification with the given \c idx.
*/
justification mk_assumption_justification(unsigned idx, pp_jst_fn const & fn, optional<expr> const & s);
/**
\brief Similar to the previous function, but fn just returns the format object "assumption idx", and s is the none.
*/
justification mk_assumption_justification(unsigned idx);
/**
\brief Create a justification for constraints produced by the type checker.
*/
justification mk_justification(pp_jst_fn const & fn, optional<expr> const & s);
/**
\brief Create a justification for constraints produced by the type checker.
It is similar to the previous function, but the position of \c s will be automatically included.
*/
justification mk_justification(pp_jst_sfn const & fn, optional<expr> const & s);
/** \brief Add \c t to \c r */
inline void push_back(buffer<justification_cell*> & r, justification const & t) {
if (t) r.push_back(t.raw());
}
/**
\brief Return the first child of a composite justification.
\pre j.is_composite()
*/
justification const & composite_child1(justification const & j);
/**
\brief Return the second child of a composite justification.
\pre j.is_composite()
*/
justification const & composite_child2(justification const & j);
/**
\brief Return the index of an assumption justification.
\pre j.is_assumption()
*/
unsigned assumption_idx(justification const & j);
/** \brief Add justifications in the collection \c s into r. */
template<typename T>
void append(buffer<justification_cell*> & r, T const & s) {
for (auto t : s)
push_back(r, t);
}
/** \brief Return true iff \c j depends on the assumption with index \c i. */
bool depends_on(justification const & j, unsigned i);
}

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@ -11,7 +11,7 @@ Author: Leonardo de Moura
namespace lean {
/**
\brief Abstract class for providing expression position information (line number and position).
\brief Abstract class for providing expression position information (line number and column).
*/
class pos_info_provider {
public:

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@ -419,6 +419,7 @@ int main() {
std::cout << "sizeof(expr_cell): " << sizeof(expr_cell) << "\n";
std::cout << "sizeof(optional<expr>): " << sizeof(optional<expr>) << "\n";
std::cout << "sizeof(optional<sexpr>): " << sizeof(optional<sexpr>) << "\n";
std::cout << "sizeof(std::function): " << sizeof(std::function<expr(expr const &, optional<expr> const &)>) << "\n";
std::cout << "done" << "\n";
return has_violations() ? 1 : 0;
}

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@ -116,11 +116,16 @@ static void tst4() {
lean_assert_eq(s.str(), "() (foo bar) nil \"test\" (100 1/2)");
}
static void tst5() {
std::cout << "{" << format() << "}" << "\n";
}
int main() {
save_stack_info();
tst1();
tst2();
tst3();
tst4();
tst5();
return has_violations() ? 1 : 0;
}