lean2/src/kernel/context.cpp
Leonardo de Moura 74cae2a154 refactor(library/elaborator): remove hackish rule
After the recent fixes, the hack in process_metavar is not needed anymore.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2014-01-01 10:55:39 -08:00

90 lines
2.5 KiB
C++

/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <utility>
#include "util/exception.h"
#include "kernel/context.h"
#include "kernel/metavar.h"
#include "kernel/free_vars.h"
namespace lean {
context::context(std::initializer_list<std::pair<char const *, expr const &>> const & l) {
for (auto const & p : l)
m_list = cons(context_entry(name(p.first), p.second), m_list);
}
std::pair<context_entry const &, context> context::lookup_ext(unsigned i) const {
list<context_entry> const * it1 = &m_list;
while (*it1) {
if (i == 0)
return std::pair<context_entry const &, context>(head(*it1), context(tail(*it1)));
--i;
it1 = &tail(*it1);
}
throw exception("unknown free variable");
}
context_entry const & context::lookup(unsigned i) const {
list<context_entry> const * it1 = &m_list;
while (*it1) {
if (i == 0)
return head(*it1);
--i;
it1 = &tail(*it1);
}
throw exception("unknown free variable");
}
optional<context_entry> context::find(unsigned i) const {
list<context_entry> const * it1 = &m_list;
while (*it1) {
if (i == 0)
return some(head(*it1));
--i;
it1 = &tail(*it1);
}
return optional<context_entry>();
}
list<context_entry> truncate_core(list<context_entry> const & l, unsigned s) {
if (s == 0) {
return list<context_entry>();
} else {
return cons(head(l), truncate_core(tail(l), s-1));
}
}
context context::truncate(unsigned s) const {
return context(truncate_core(m_list, s));
}
struct remove_no_applicable {};
static list<context_entry> remove_core(list<context_entry> const & l, unsigned s, unsigned n, metavar_env const & menv) {
if (l) {
if (s == 0) {
if (n > 0) {
return remove_core(tail(l), 0, n-1, menv);
} else {
return l;
}
} else {
if (has_free_var(head(l), s-1, s+n-1, menv))
throw remove_no_applicable();
return cons(lower_free_vars(head(l), s+n-1, n, menv), remove_core(tail(l), s-1, n, menv));
}
} else {
return l;
}
}
optional<context> context::remove(unsigned s, unsigned n, metavar_env const & menv) const {
try {
return some(context(remove_core(m_list, s, n, menv)));
} catch (remove_no_applicable&) {
return optional<context>();
}
}
}