lean2/src/kernel/formatter.cpp

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/*
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 <utility>
#include "kernel/formatter.h"
#include "kernel/environment.h"
#include "kernel/find_fn.h"
#include "kernel/instantiate.h"
#include "kernel/free_vars.h"
namespace lean {
bool is_used_name(expr const & t, name const & n) {
return static_cast<bool>(
find(t, [&](expr const & e, unsigned) {
return (is_constant(e) && const_name(e) == n) // t has a constant named n
|| (is_local(e) && (mlocal_name(e) == n || local_pp_name(e) == n)); // t has a local constant named n
}));
}
name pick_unused_name(expr const & t, name const & s) {
name r = s;
unsigned i = 1;
while (is_used_name(t, r)) {
r = name(s).append_after(i);
i++;
}
return r;
}
std::pair<expr, expr> binding_body_fresh(expr const & b, bool preserve_type) {
lean_assert(is_binding(b));
name n = pick_unused_name(binding_body(b), binding_name(b));
expr c = mk_local(n, n, preserve_type ? binding_domain(b) : expr());
return mk_pair(instantiate(binding_body(b), c), c);
}
std::pair<expr, expr> let_body_fresh(expr const & l, bool preserve_type) {
lean_assert(is_let(l));
name n = pick_unused_name(let_body(l), let_name(l));
expr c = mk_local(n, n, preserve_type ? let_type(l) : expr());
return mk_pair(instantiate(let_body(l), c), c);
}
/**
\brief Very basic printer for expressions.
It is mainly used when debugging code.
*/
struct print_expr_fn {
std::ostream & m_out;
bool m_type0_as_bool;
std::ostream & out() { return m_out; }
bool is_atomic(expr const & a) {
return ::lean::is_atomic(a) || is_mlocal(a);
}
void print_child(expr const & a) {
if (is_atomic(a)) {
print(a);
} else {
out() << "("; print(a); out() << ")";
}
}
void print_macro(expr const & a) {
macro_def(a).display(out());
for (unsigned i = 0; i < macro_num_args(a); i++) {
out() << " "; print_child(macro_arg(a, i));
}
}
void print_sort(expr const & a) {
if (is_zero(sort_level(a))) {
if (m_type0_as_bool)
out() << "Bool";
else
out() << "Type";
} else if (m_type0_as_bool && is_one(sort_level(a))) {
out() << "Type";
} else {
out() << "Type.{" << sort_level(a) << "}";
}
}
void print_app(expr const & e) {
expr const & f = app_fn(e);
if (is_app(f))
print(f);
else
print_child(f);
out() << " ";
print_child(app_arg(e));
}
void print_arrow_body(expr const & a) {
if (is_atomic(a) || is_arrow(a))
return print(a);
else
return print_child(a);
}
void print_let(expr const & a) {
auto p = let_body_fresh(a);
expr const & b = p.first;
expr const & n = p.second;
out() << "let " << n;
out() << " : ";
print(let_type(a));
out() << " := ";
print(let_value(a));
out() << " in ";
print_child(b);
}
void print_binding(char const * bname, expr e) {
expr_kind k = e.kind();
out() << bname;
while (e.kind() == k) {
out() << " ";
auto p = binding_body_fresh(e);
expr const & n = p.second;
if (binding_info(e).is_implicit())
out() << "{";
else if (binding_info(e).is_cast())
out() << "[";
else
out() << "(";
out() << n << " : ";
print(binding_domain(e));
if (binding_info(e).is_implicit())
out() << "}";
else if (binding_info(e).is_cast())
out() << "]";
else
out() << ")";
e = p.first;
}
out() << ", ";
print_child(e);
}
void print_const(expr const & a) {
list<level> const & ls = const_levels(a);
out() << const_name(a);
if (!is_nil(ls)) {
out() << ".{";
bool first = true;
for (auto l : ls) {
if (first) first = false; else out() << " ";
out() << l;
}
out() << "}";
}
}
void print(expr const & a) {
switch (a.kind()) {
case expr_kind::Meta:
out() << "?" << mlocal_name(a);
break;
case expr_kind::Local:
out() << local_pp_name(a);
break;
case expr_kind::Var:
out() << "#" << var_idx(a);
break;
case expr_kind::Constant:
print_const(a);
break;
case expr_kind::App:
print_app(a);
break;
case expr_kind::Lambda:
print_binding("fun", a);
break;
case expr_kind::Pi:
if (!is_arrow(a)) {
print_binding("Pi", a);
} else {
print_child(binding_domain(a));
out() << " -> ";
print_arrow_body(lower_free_vars(binding_body(a), 1));
}
break;
case expr_kind::Let:
print_let(a);
break;
case expr_kind::Sort:
print_sort(a);
break;
case expr_kind::Macro:
print_macro(a);
break;
}
}
print_expr_fn(std::ostream & out, bool type0_as_bool = true):m_out(out), m_type0_as_bool(type0_as_bool) {}
void operator()(expr const & e) {
scoped_expr_caching set(false);
print(e);
}
};
std::ostream & operator<<(std::ostream & out, expr const & e) {
print_expr_fn pr(out);
pr(e);
return out;
}
class simple_formatter_cell : public formatter_cell {
public:
virtual format operator()(environment const & env, expr const & e, options const &) const {
std::ostringstream s;
print_expr_fn pr(s, env.prop_proof_irrel());
pr(e);
return format(s.str());
}
};
formatter mk_simple_formatter() {
return mk_formatter(simple_formatter_cell());
}
void print(lean::expr const & a) { std::cout << a << std::endl; }
}