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refactor(kernel/converter): cleanup and remove universe cumulativity support

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-05-09 20:43:11 -07:00
parent e942aecca6
commit 7176181b42
3 changed files with 23 additions and 76 deletions
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75
src/kernel/converter.cpp
View file

@ -12,11 +12,6 @@ Author: Leonardo de Moura
#include "kernel/free_vars.h"
namespace lean {
bool converter::is_conv(expr const & t, expr const & s, context & c) {
delayed_justification j([]() { return justification(); });
return is_conv(t, s, c, j);
}
bool converter::is_def_eq(expr const & t, expr const & s, context & c) {
delayed_justification j([]() { return justification(); });
return is_def_eq(t, s, c, j);
@ -25,7 +20,6 @@ bool converter::is_def_eq(expr const & t, expr const & s, context & c) {
/** \brief Do nothing converter */
struct dummy_converter : public converter {
virtual expr whnf(expr const & e, context &) { return e; }
virtual bool is_conv(expr const &, expr const &, context &, delayed_justification &) { return true; }
virtual bool is_def_eq(expr const &, expr const &, context &, delayed_justification &) { return true; }
};
@ -282,25 +276,15 @@ struct default_converter : public converter {
}
/**
\brief Given lambda/Pi expressions \c t and \c s, return true iff \c t is convertible to \c s.
\brief Given lambda/Pi expressions \c t and \c s, return true iff \c t is def eq to \c s.
The argument \c def_eq is used to decide whether the body of the binder is checked for
definitional equality or convertability.
If t and s are lambda expressions, then then t is convertible to s
t and s are definitionally equal
iff
domain(t) is definitionally equal to domain(s)
and
body(t) is definitionally equal to body(s)
For Pi expressions, it is slighly different.
If t and s are Pi expressions, then then t is convertible to s
iff
domain(t) is definitionally equal to domain(s)
and
body(t) is convertible to body(s)
*/
bool is_conv_binder(expr t, expr s, bool def_eq, context & c, delayed_justification & jst) {
bool is_def_eq_binder(expr t, expr s, context & c, delayed_justification & jst) {
lean_assert(t.kind() == s.kind());
lean_assert(is_binder(t));
expr_kind k = t.kind();
@ -314,15 +298,11 @@ struct default_converter : public converter {
t = binder_body(t);
s = binder_body(s);
} while (t.kind() == k && s.kind() == k);
return is_conv(instantiate(t, subst.size(), subst.data()), instantiate(s, subst.size(), subst.data()), def_eq, c, jst);
return is_def_eq(instantiate(t, subst.size(), subst.data()), instantiate(s, subst.size(), subst.data()), c, jst);
}
/**
\brief This is an auxiliary method for is_conv. It handles the "easy cases".
If \c def_eq is true, then it checks for definitional equality.
*/
lbool quick_is_conv(expr const & t, expr const & s, bool def_eq, context & c, delayed_justification & jst) {
/** \brief This is an auxiliary method for is_def_eq. It handles the "easy cases". */
lbool quick_is_def_eq(expr const & t, expr const & s, context & c, delayed_justification & jst) {
if (t == s)
return l_true; // t and s are structurally equal
if (is_meta(t) || is_meta(s)) {
@ -332,17 +312,13 @@ struct default_converter : public converter {
}
if (t.kind() == s.kind()) {
switch (t.kind()) {
case expr_kind::Lambda:
return to_lbool(is_conv_binder(t, s, true, c, jst));
case expr_kind::Pi:
return to_lbool(is_conv_binder(t, s, def_eq, c, jst));
case expr_kind::Lambda: case expr_kind::Pi:
return to_lbool(is_def_eq_binder(t, s, c, jst));
case expr_kind::Sort:
// t and s are Sorts
if (is_trivial(sort_level(t), sort_level(s)) && (!def_eq || is_trivial(sort_level(s), sort_level(t))))
if (is_trivial(sort_level(t), sort_level(s)))
return l_true;
c.add_cnstr(mk_level_cnstr(sort_level(t), sort_level(s), jst.get()));
if (def_eq)
c.add_cnstr(mk_level_cnstr(sort_level(s), sort_level(t), jst.get()));
return l_true;
case expr_kind::Meta:
lean_unreachable(); // LCOV_EXCL_LINE
@ -357,11 +333,9 @@ struct default_converter : public converter {
/**
\brief Return true if arguments of \c t are definitionally equal to arguments of \c s.
Constraint generation is disabled when performing this test.
This method is used to implement an optimization in the method \c is_conv.
This method is used to implement an optimization in the method \c is_def_eq.
*/
bool is_def_eq_args(expr t, expr s, context & c, delayed_justification & jst) {
context::disable_cnstrs_scope scope(c);
try {
while (is_app(t) && is_app(s)) {
if (!is_def_eq(app_arg(t), app_arg(s), c, jst))
@ -375,20 +349,17 @@ struct default_converter : public converter {
}
}
/**
\brief If def_eq is false, then return true iff t is convertible to s.
If def_eq is true, then return true iff t is definitionally equal to s.
*/
bool is_conv(expr const & t, expr const & s, bool def_eq, context & c, delayed_justification & jst) {
check_system("is_convertible");
lbool r = quick_is_conv(t, s, def_eq, c, jst);
/** Return true iff t is definitionally equal to s. */
virtual bool is_def_eq(expr const & t, expr const & s, context & c, delayed_justification & jst) {
check_system("is_definitionally_equal");
lbool r = quick_is_def_eq(t, s, c, jst);
if (r != l_undef) return r == l_true;
// apply whnf (without using delta-reduction or normalizer extensions)
expr t_n = whnf_core(t, c);
expr s_n = whnf_core(s, c);
if (!is_eqp(t_n, t) || !is_eqp(s_n, s)) {
r = quick_is_conv(t_n, s_n, def_eq, c, jst);
r = quick_is_def_eq(t_n, s_n, c, jst);
if (r != l_undef) return r == l_true;
}
@ -414,8 +385,12 @@ struct default_converter : public converter {
// then we try to check if their arguments are definitionally equal.
// If they are, then t_n and s_n must be definitionally equal, and we can
// skip the delta-reduction step.
// We only apply the optimization if t_n and s_n do not contain metavariables.
// In this way we don't have to backtrack constraints if the optimization fail.
if (is_app(t_n) && is_app(s_n) &&
is_eqp(*d_t, *d_s) && // same definition
!has_metavar(t_n) &&
!has_metavar(s_n) &&
!is_opaque(*d_t) && // if d_t is opaque, we don't need to try this optimization
d_t->use_conv_opt() && // the flag use_conv_opt() can be used to disable this optimization
is_def_eq_args(t_n, s_n, c, jst)) {
@ -424,7 +399,7 @@ struct default_converter : public converter {
t_n = whnf_core(unfold_names(t_n, d_t->get_weight() - 1), c);
s_n = whnf_core(unfold_names(s_n, d_s->get_weight() - 1), c);
}
r = quick_is_conv(t_n, s_n, def_eq, c, jst);
r = quick_is_def_eq(t_n, s_n, c, jst);
if (r != l_undef) return r == l_true;
}
// try normalizer extensions
@ -436,7 +411,7 @@ struct default_converter : public converter {
t_n = whnf_core(*new_t_n, c);
if (new_s_n)
s_n = whnf_core(*new_s_n, c);
r = quick_is_conv(t_n, s_n, def_eq, c, jst);
r = quick_is_def_eq(t_n, s_n, c, jst);
if (r != l_undef) return r == l_true;
}
@ -478,14 +453,6 @@ struct default_converter : public converter {
bool is_prop(expr const & e, context & c) {
return whnf(c.infer_type(e), c) == Bool;
}
virtual bool is_def_eq(expr const & t, expr const & s, context & c, delayed_justification & j) {
return is_conv(t, s, true, c, j);
}
virtual bool is_conv(expr const & t, expr const & s, context & c, delayed_justification & j) {
return is_conv(t, s, false, c, j);
}
};
std::unique_ptr<converter> mk_default_converter(environment const & env, optional<module_idx> mod_idx,

10
src/kernel/converter.h
View file

@ -24,26 +24,16 @@ class converter {
public:
/** \brief Abstract context that must be provided to a converter object. */
class context {
virtual bool enable_cnstrs(bool flag) = 0;
public:
virtual name mk_fresh_name() = 0;
virtual expr infer_type(expr const & e) = 0;
virtual void add_cnstr(constraint const & c) = 0;
class disable_cnstrs_scope {
context & m_ctx;
bool m_old;
public:
disable_cnstrs_scope(context & ctx):m_ctx(ctx), m_old(m_ctx.enable_cnstrs(false)) {}
~disable_cnstrs_scope() { m_ctx.enable_cnstrs(m_old); }
};
};
virtual ~converter() {}
virtual expr whnf(expr const & e, context & c) = 0;
virtual bool is_conv(expr const & t, expr const & s, context & c, delayed_justification & j) = 0;
virtual bool is_def_eq(expr const & t, expr const & s, context & c, delayed_justification & j) = 0;
bool is_conv(expr const & t, expr const & s, context & c);
bool is_def_eq(expr const & t, expr const & s, context & c);
};

14
src/kernel/type_checker.cpp
View file

@ -36,12 +36,6 @@ struct type_checker::imp {
/** \brief Interface type_checker <-> converter */
class converter_context : public converter::context {
imp & m_imp;
virtual bool enable_cnstrs(bool flag) {
bool r = m_imp.m_cnstrs_enabled;
m_imp.m_cnstrs_enabled = flag;
return r;
}
public:
converter_context(imp & i):m_imp(i) {}
virtual name mk_fresh_name() { return m_imp.m_gen.next(); }
@ -74,12 +68,11 @@ struct type_checker::imp {
expr_map<expr> m_trace;
bool m_memoize;
// temp flag
bool m_cnstrs_enabled;
param_names m_params;
imp(environment const & env, name_generator const & g, constraint_handler & h, std::unique_ptr<converter> && conv, bool memoize):
m_env(env), m_gen(g), m_chandler(h), m_conv(std::move(conv)), m_conv_ctx(*this), m_tc_ctx(*this),
m_memoize(memoize), m_cnstrs_enabled(true) {}
m_memoize(memoize) {}
optional<expr> expand_macro(expr const & m) {
lean_assert(is_macro(m));
@ -122,10 +115,7 @@ struct type_checker::imp {
/** \brief Add given constraint to the constraint handler m_chandler. */
void add_cnstr(constraint const & c) {
if (m_cnstrs_enabled)
m_chandler.add_cnstr(c);
else
throw add_cnstr_exception();
m_chandler.add_cnstr(c);
}
/** \brief Return true iff \c t and \c s are definitionally equal */