lean4-htt/src/library/print.cpp
2021-09-20 18:41:46 +02:00

311 lines
8.5 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 <string>
#include <utility>
#include "util/escaped.h"
#include "kernel/environment.h"
#include "kernel/find_fn.h"
#include "kernel/instantiate.h"
#include "library/formatter.h"
#include "library/annotation.h"
#include "library/util.h"
#include "library/print.h"
namespace lean {
bool is_used_name(expr const & t, name const & n) {
bool found = false;
for_each(t, [&](expr const & e, unsigned) {
if (found) return false; // already found
if ((is_constant(e) && const_name(e).get_root() == n) // t has a constant starting with n
|| (is_fvar(e) && fvar_name(e) == n)) {
found = true;
return false; // found it
}
return true; // continue search
});
return found;
}
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;
}
bool is_numerical_name(name n) {
while (!n.is_atomic())
n = n.get_prefix();
return n.is_numeral();
}
static name * g_M = nullptr;
static name * g_x = nullptr;
void initialize_print() {
g_M = new name("M");
mark_persistent(g_M->raw());
g_x = new name("x");
mark_persistent(g_x->raw());
}
void finalize_print() {
delete g_M;
delete g_x;
}
static name cleanup_name(name const & n) {
if (is_numerical_name(n))
return *g_x;
else
return n;
}
pair<expr, expr> binding_body_fresh(expr const & b, bool /* preserve_type */) {
lean_assert(is_binding(b));
name n = cleanup_name(binding_name(b));
n = pick_unused_name(binding_body(b), n);
expr c = mk_fvar(n); // HACK
return mk_pair(instantiate(binding_body(b), c), c);
}
pair<expr, expr> let_body_fresh(expr const & b, bool /* preserve_type */) {
lean_assert(is_let(b));
name n = cleanup_name(let_name(b));
n = pick_unused_name(let_body(b), n);
expr c = mk_fvar(n); // HACK
return mk_pair(instantiate(let_body(b), c), c);
}
name fix_name(name const & a) {
if (a.is_atomic()) {
if (a.is_numeral())
return *g_M;
else
return a;
} else {
name p = fix_name(a.get_prefix());
if (p == a.get_prefix())
return a;
else if (a.is_numeral())
return name(p, a.get_numeral());
else
return name(p, a.get_string());
}
}
/**
\brief Very basic printer for expressions.
It is mainly used when debugging code.
*/
struct print_expr_fn {
std::ostream & m_out;
std::ostream & out() { return m_out; }
static bool is_atomic(expr const & a) {
if (::lean::is_atomic(a)) return true;
if (is_proj(a)) return is_atomic(proj_expr(a));
return false;
}
void print_child(expr const & a) {
if (is_atomic(a)) {
print(a);
} else {
out() << "("; print(a); out() << ")";
}
}
void print_sort(expr const & a) {
if (is_zero(sort_level(a))) {
out() << "Prop";
} else if (is_one(sort_level(a))) {
out() << "Type";
} else if (is_succ(sort_level(a))) {
out() << "Type.{" << succ_of(sort_level(a)) << "}";
} else {
out() << "Sort.{" << 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));
}
static bool is_arrow(expr const & t) {
return lean::is_arrow(t) && binding_info(t) == binder_info::Default;
}
void print_arrow_body(expr const & a) {
if (is_atomic(a) || is_arrow(a))
return print(a);
else
return print_child(a);
}
void print_binding(char const * bname, expr e, bool is_lambda) {
expr_kind k = e.kind();
out() << bname;
while (e.kind() == k && !is_arrow(e)) {
out() << " ";
auto p = binding_body_fresh(e);
expr const & n = p.second;
binder_info bi = binding_info(e);
if (is_implicit(bi))
out() << "{";
else if (is_inst_implicit(bi))
out() << "[";
else if (is_strict_implicit(bi))
out() << "{{";
else
out() << "(";
out() << n << " : ";
print(binding_domain(e));
if (is_implicit(bi))
out() << "}";
else if (is_inst_implicit(bi))
out() << "]";
else if (is_strict_implicit(bi))
out() << "}}";
else
out() << ")";
e = p.first;
}
if (is_lambda) out() << " => ";
else out() << ", ";
print(e);
}
void print_let(expr const & e) {
auto p = let_body_fresh(e);
out() << "let " << p.second << " : ";
print(let_type(e));
out() << " := ";
print(let_value(e));
out() << "; ";
print(p.first);
}
void print_const(expr const & a) {
levels 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() << " ";
if (is_max(l) || is_imax(l))
out() << "(" << l << ")";
else
out() << l;
}
out() << "}";
}
}
void print_mdata(expr const & a) {
out() << "[mdata ";
auto k = mdata_data(a);
while (!empty(k)) {
out() << head(k).fst() << ":";
auto const & v = head(k).snd();
switch (v.kind()) {
case data_value_kind::Bool: out() << v.get_bool(); break;
case data_value_kind::Name: out() << v.get_name(); break;
case data_value_kind::Nat: out() << v.get_nat(); break;
case data_value_kind::String: out() << escaped(v.get_string().data()); break;
}
out() << " ";
k = tail(k);
}
print(mdata_expr(a));
out() << "]";
}
void print(expr const & a) {
switch (a.kind()) {
case expr_kind::MVar:
out() << "?" << fix_name(mvar_name(a));
break;
case expr_kind::FVar:
out() << fvar_name(a);
break;
case expr_kind::MData:
print_mdata(a);
break;
case expr_kind::Proj:
print_child(proj_expr(a));
out() << "." << proj_idx(a).to_mpz();
break;
case expr_kind::BVar:
out() << "#" << bvar_idx(a);
break;
case expr_kind::Const:
print_const(a);
break;
case expr_kind::App:
print_app(a);
break;
case expr_kind::Let:
print_let(a);
break;
case expr_kind::Lambda:
print_binding("fun", a, true);
break;
case expr_kind::Pi:
if (!is_arrow(a)) {
print_binding("forall", a, false);
} else {
print_child(binding_domain(a));
out() << " -> ";
print_arrow_body(lower_loose_bvars(binding_body(a), 1));
}
break;
case expr_kind::Sort:
print_sort(a);
break;
case expr_kind::Lit:
switch (lit_value(a).kind()) {
case literal_kind::Nat: out() << lit_value(a).get_nat().to_mpz(); break;
case literal_kind::String: {
std::string val(lit_value(a).get_string().to_std_string());
out() << "\"" << escaped(val.c_str()) << "\""; break; // HACK Lean string as C string
}}
break;
}
}
print_expr_fn(std::ostream & out):m_out(out) {}
void operator()(expr const & e) {
print(e);
}
};
void init_default_print_fn() {
set_print_fn([](std::ostream & out, expr const & e) {
print_expr_fn pr(out);
pr(e);
});
}
extern "C" LEAN_EXPORT object * lean_expr_dbg_to_string(b_obj_arg e) {
std::ostringstream out;
out << expr(e, true);
return mk_string(out.str());
}
}