lean2/src/frontends/lean/util.cpp

359 lines
13 KiB
C++

/*
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <algorithm>
#include "util/sstream.h"
#include "kernel/abstract.h"
#include "kernel/instantiate.h"
#include "kernel/replace_fn.h"
#include "kernel/error_msgs.h"
#include "kernel/for_each_fn.h"
#include "library/scoped_ext.h"
#include "library/locals.h"
#include "library/explicit.h"
#include "frontends/lean/parser.h"
#include "frontends/lean/tokens.h"
namespace lean {
bool parse_persistent(parser & p, bool & persistent) {
if (p.curr_is_token_or_id(get_persistent_tk())) {
p.next();
persistent = true;
return true;
} else {
return false;
}
}
void check_atomic(name const & n) {
if (!n.is_atomic())
throw exception(sstream() << "invalid declaration name '" << n << "', identifier must be atomic");
}
void check_in_context(parser const & p) {
if (!in_context(p.env()))
throw exception(sstream() << "invalid command, it must be used in a (local) context");
}
bool is_root_namespace(name const & n) {
return n == get_root_tk();
}
name remove_root_prefix(name const & n) {
return n.replace_prefix(get_root_tk(), name());
}
// Sort local names by order of occurrence, and copy the associated parameters to ps
void sort_locals(expr_struct_set const & locals, parser const & p, buffer<expr> & ps) {
for (expr const & l : locals)
ps.push_back(l);
std::sort(ps.begin(), ps.end(), [&](expr const & p1, expr const & p2) {
bool is_var1 = p.is_local_variable(p1);
bool is_var2 = p.is_local_variable(p2);
if (!is_var1 && is_var2)
return true;
else if (is_var1 && !is_var2)
return false;
else
return p.get_local_index(p1) < p.get_local_index(p2);
});
}
// Return the local levels in \c ls that are not associated with variables
levels collect_local_nonvar_levels(parser & p, level_param_names const & ls) {
buffer<level> section_ls_buffer;
for (name const & l : ls) {
if (p.get_local_level_index(l) && !p.is_local_level_variable(l))
section_ls_buffer.push_back(mk_param_univ(l));
else
break;
}
return to_list(section_ls_buffer.begin(), section_ls_buffer.end());
}
// Collect local constants occurring in type and value, sort them, and store in ctx_ps
void collect_locals(expr const & type, expr const & value, parser const & p, buffer<expr> & ctx_ps) {
expr_struct_set ls;
buffer<expr> include_vars;
p.get_include_variables(include_vars);
for (expr const & param : include_vars) {
collect_locals(mlocal_type(param), ls);
ls.insert(param);
}
collect_locals(type, ls);
collect_locals(value, ls);
sort_locals(ls, p, ctx_ps);
}
void remove_local_vars(parser const & p, buffer<expr> & locals) {
unsigned j = 0;
for (unsigned i = 0; i < locals.size(); i++) {
expr const & param = locals[i];
if (!is_local(param) || !p.is_local_variable(param)) {
locals[j] = param;
j++;
}
}
locals.shrink(j);
}
list<expr> locals_to_context(expr const & e, parser const & p) {
expr_struct_set ls;
collect_locals(e, ls);
buffer<expr> locals;
sort_locals(ls, p, locals);
std::reverse(locals.begin(), locals.end());
return to_list(locals.begin(), locals.end());
}
expr mk_local_ref(name const & n, levels const & ctx_ls, unsigned num_ctx_params, expr const * ctx_params) {
buffer<expr> params;
for (unsigned i = 0; i < num_ctx_params; i++)
params.push_back(mk_explicit(ctx_params[i]));
return mk_as_atomic(mk_app(mk_explicit(mk_constant(n, ctx_ls)), params));
}
bool is_local_ref(expr const & e) {
if (!is_as_atomic(e))
return false;
expr const & imp_arg = get_as_atomic_arg(e);
if (!is_app(imp_arg))
return false;
buffer<expr> locals;
expr const & f = get_app_args(imp_arg, locals);
return
is_explicit(f) &&
is_constant(get_explicit_arg(f)) &&
std::all_of(locals.begin(), locals.end(),
[](expr const & l) {
return is_explicit(l) && is_local(get_explicit_arg(l));
});
}
expr update_local_ref(expr const & e, name_set const & lvls_to_remove, name_set const & locals_to_remove) {
lean_assert(is_local_ref(e));
if (locals_to_remove.empty() && lvls_to_remove.empty())
return e;
buffer<expr> locals;
expr const & f = get_app_args(get_as_atomic_arg(e), locals);
lean_assert(is_explicit(f));
expr new_f;
if (!lvls_to_remove.empty()) {
expr const & c = get_explicit_arg(f);
lean_assert(is_constant(c));
new_f = mk_explicit(update_constant(c, filter(const_levels(c), [&](level const & l) {
return is_param(l) && !lvls_to_remove.contains(param_id(l));
})));
} else {
new_f = f;
}
if (!locals_to_remove.empty()) {
unsigned j = 0;
for (unsigned i = 0; i < locals.size(); i++) {
expr const & l = locals[i];
if (!locals_to_remove.contains(mlocal_name(get_explicit_arg(l)))) {
locals[j] = l;
j++;
}
}
locals.shrink(j);
}
if (locals.empty()) {
return get_explicit_arg(new_f);
} else {
return mk_as_atomic(mk_app(new_f, locals));
}
}
expr Fun(buffer<expr> const & locals, expr const & e, parser & p) {
bool use_cache = false;
return p.rec_save_pos(Fun(locals, e, use_cache), p.pos_of(e));
}
expr Pi(buffer<expr> const & locals, expr const & e, parser & p) {
bool use_cache = false;
return p.rec_save_pos(Pi(locals, e, use_cache), p.pos_of(e));
}
template<bool is_lambda>
static expr mk_binding_as_is(unsigned num, expr const * locals, expr const & b) {
expr r = abstract_locals(b, num, locals);
unsigned i = num;
while (i > 0) {
--i;
expr const & l = locals[i];
expr t = abstract_locals(mlocal_type(l), i, locals);
if (is_lambda)
r = mk_lambda(local_pp_name(l), mk_as_is(t), r, local_info(l));
else
r = mk_pi(local_pp_name(l), mk_as_is(t), r, local_info(l));
}
return r;
}
expr Fun_as_is(buffer<expr> const & locals, expr const & e, parser & p) {
return p.rec_save_pos(mk_binding_as_is<true>(locals.size(), locals.data(), e), p.pos_of(e));
}
expr Pi_as_is(buffer<expr> const & locals, expr const & e, parser & p) {
return p.rec_save_pos(mk_binding_as_is<false>(locals.size(), locals.data(), e), p.pos_of(e));
}
level mk_result_level(environment const & env, buffer<level> const & r_lvls) {
bool impredicative = env.impredicative();
if (r_lvls.empty()) {
return impredicative ? mk_level_one() : mk_level_zero();
} else {
level r = r_lvls[0];
for (unsigned i = 1; i < r_lvls.size(); i++)
r = mk_max(r, r_lvls[i]);
r = normalize(r);
if (is_not_zero(r))
return normalize(r);
else
return impredicative ? normalize(mk_max(r, mk_level_one())) : normalize(r);
}
}
bool occurs(level const & u, level const & l) {
bool found = false;
for_each(l, [&](level const & l) {
if (found) return false;
if (l == u) { found = true; return false; }
return true;
});
return found;
}
/** \brief Functional object for converting the universe metavariables in an expression in new universe parameters.
The substitution is updated with the mapping metavar -> new param.
The set of parameter names m_params and the buffer m_new_params are also updated.
*/
class univ_metavars_to_params_fn {
environment const & m_env;
local_decls<level> const & m_lls;
substitution & m_subst;
name_set & m_params;
buffer<name> & m_new_params;
unsigned m_next_idx;
/** \brief Create a new universe parameter s.t. the new name does not occur in \c m_params, nor it is
a global universe in \e m_env or in the local_decls<level> m_lls.
The new name is added to \c m_params, and the new level parameter is returned.
The name is of the form "l_i" where \c i >= m_next_idx.
*/
level mk_new_univ_param() {
name l("l");
name r = l.append_after(m_next_idx);
while (m_lls.contains(r) || m_params.contains(r) || m_env.is_universe(r)) {
m_next_idx++;
r = l.append_after(m_next_idx);
}
m_params.insert(r);
m_new_params.push_back(r);
return mk_param_univ(r);
}
public:
univ_metavars_to_params_fn(environment const & env, local_decls<level> const & lls, substitution & s,
name_set & ps, buffer<name> & new_ps):
m_env(env), m_lls(lls), m_subst(s), m_params(ps), m_new_params(new_ps), m_next_idx(1) {}
level apply(level const & l) {
return replace(l, [&](level const & l) {
if (!has_meta(l))
return some_level(l);
if (is_meta(l)) {
if (auto it = m_subst.get_level(meta_id(l))) {
return some_level(*it);
} else {
level new_p = mk_new_univ_param();
m_subst.assign(l, new_p);
return some_level(new_p);
}
}
return none_level();
});
}
expr apply(expr const & e) {
if (!has_univ_metavar(e)) {
return e;
} else {
return replace(e, [&](expr const & e) {
if (!has_univ_metavar(e)) {
return some_expr(e);
} else if (is_sort(e)) {
return some_expr(update_sort(e, apply(sort_level(e))));
} else if (is_constant(e)) {
levels ls = map(const_levels(e), [&](level const & l) { return apply(l); });
return some_expr(update_constant(e, ls));
} else {
return none_expr();
}
});
}
}
expr operator()(expr const & e) { return apply(e); }
};
expr univ_metavars_to_params(environment const & env, local_decls<level> const & lls, substitution & s,
name_set & ps, buffer<name> & new_ps, expr const & e) {
return univ_metavars_to_params_fn(env, lls, s, ps, new_ps)(e);
}
expr instantiate_meta(expr const & meta, substitution & subst) {
lean_assert(is_meta(meta));
buffer<expr> locals;
expr mvar = get_app_args(meta, locals);
mvar = update_mlocal(mvar, subst.instantiate_all(mlocal_type(mvar)));
for (auto & local : locals)
local = subst.instantiate_all(local);
return mk_app(mvar, locals);
}
justification mk_failed_to_synthesize_jst(environment const & env, expr const & m) {
return mk_justification(m, [=](formatter const & fmt, substitution const & subst) {
substitution tmp(subst);
expr new_m = instantiate_meta(m, tmp);
expr new_type = type_checker(env).infer(new_m).first;
proof_state ps = to_proof_state(new_m, new_type, name_generator("dontcare"));
return format("failed to synthesize placeholder") + line() + ps.pp(fmt);
});
}
justification mk_type_mismatch_jst(expr const & v, expr const & v_type, expr const & t, expr const & src) {
return mk_justification(src, [=](formatter const & fmt, substitution const & subst) {
substitution s(subst);
format expected_fmt, given_fmt;
std::tie(expected_fmt, given_fmt) = pp_until_different(fmt, s.instantiate(t), s.instantiate(v_type));
format r("type mismatch at term");
r += pp_indent_expr(fmt, s.instantiate(v));
r += compose(line(), format("has type"));
r += given_fmt;
r += compose(line(), format("but is expected to have type"));
r += expected_fmt;
return r;
});
}
pair<expr, justification> update_meta(expr const & meta, substitution s) {
buffer<expr> args;
expr mvar = get_app_args(meta, args);
justification j;
auto p = s.instantiate_metavars(mlocal_type(mvar));
mvar = update_mlocal(mvar, p.first);
j = p.second;
for (expr & arg : args) {
auto p = s.instantiate_metavars(mlocal_type(arg));
arg = update_mlocal(arg, p.first);
j = mk_composite1(j, p.second);
}
return mk_pair(mk_app(mvar, args), j);
}
}