196 lines
6.6 KiB
C++
196 lines
6.6 KiB
C++
/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include <vector>
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#include "expr.h"
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#include "sets.h"
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#include "hash.h"
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namespace lean {
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unsigned hash_args(unsigned size, expr const * args) {
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return hash(size, [&args](unsigned i){ return args[i].hash(); });
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}
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unsigned hash_vars(unsigned size, uvar const * vars) {
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return hash(size, [&vars](unsigned i){ return vars[i].second.hash(); });
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}
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expr_cell::expr_cell(expr_kind k, unsigned h):
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m_kind(static_cast<unsigned>(k)),
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m_max_shared(0),
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m_closed(0),
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m_hash(h),
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m_rc(1) {}
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expr_var::expr_var(unsigned idx):
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expr_cell(expr_kind::Var, idx),
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m_vidx(idx) {}
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expr_const::expr_const(name const & n, unsigned pos):
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expr_cell(expr_kind::Constant, n.hash()),
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m_name(n),
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m_pos(pos) {}
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expr_app::expr_app(unsigned num_args):
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expr_cell(expr_kind::App, 0),
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m_num_args(num_args) {
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}
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expr_app::~expr_app() {
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for (unsigned i = 0; i < m_num_args; i++)
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(m_args+i)->~expr();
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}
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expr app(unsigned num_args, expr const * args) {
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lean_assert(num_args > 1);
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unsigned _num_args;
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unsigned _num_args0 = 0;
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expr const & arg0 = args[0];
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// Remark: we represet ((app a b) c) as (app a b c)
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if (is_app(arg0)) {
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_num_args0 = get_num_args(arg0);
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_num_args = num_args + _num_args0 - 1;
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}
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else {
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_num_args = num_args;
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}
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char * mem = new char[sizeof(expr_app) + _num_args*sizeof(expr)];
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expr r(new (mem) expr_app(_num_args));
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expr * m_args = to_app(r)->m_args;
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unsigned i = 0;
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unsigned j = 0;
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if (_num_args != num_args) {
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for (; i < _num_args0; i++)
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new (m_args+i) expr(get_arg(arg0, i));
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j++;
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}
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for (; i < _num_args; ++i, ++j) {
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lean_assert(j < num_args);
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new (m_args+i) expr(args[j]);
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}
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to_app(r)->m_hash = hash_args(_num_args, m_args);
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return r;
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}
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expr_abstraction::expr_abstraction(expr_kind k, name const & n, expr const & t, expr const & e):
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expr_cell(k, ::lean::hash(t.hash(), e.hash())),
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m_name(n),
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m_type(t),
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m_expr(e) {
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}
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expr_lambda::expr_lambda(name const & n, expr const & t, expr const & e):
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expr_abstraction(expr_kind::Lambda, n, t, e) {}
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expr_pi::expr_pi(name const & n, expr const & t, expr const & e):
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expr_abstraction(expr_kind::Pi, n, t, e) {}
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expr_type::expr_type(unsigned size, uvar const * vars):
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expr_cell(expr_kind::Type, hash_vars(size, vars)),
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m_size(size) {
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for (unsigned i = 0; i < m_size; i++)
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new (m_vars + i) uvar(vars[i]);
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}
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expr_type::~expr_type() {
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for (unsigned i = 0; i < m_size; i++)
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(m_vars+i)->~uvar();
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}
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expr type(unsigned size, uvar const * vars) {
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char * mem = new char[sizeof(expr_type) + size*sizeof(uvar)];
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return expr(new (mem) expr_type(size, vars));
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}
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expr_numeral::expr_numeral(mpz const & n):
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expr_cell(expr_kind::Numeral, n.hash()),
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m_numeral(n) {}
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void expr_cell::dealloc() {
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switch (kind()) {
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case expr_kind::Var: delete static_cast<expr_var*>(this); break;
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case expr_kind::Constant: delete static_cast<expr_const*>(this); break;
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case expr_kind::App: static_cast<expr_app*>(this)->~expr_app(); delete[] reinterpret_cast<char*>(this); break;
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case expr_kind::Lambda: delete static_cast<expr_lambda*>(this); break;
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case expr_kind::Pi: delete static_cast<expr_pi*>(this); break;
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case expr_kind::Prop: delete static_cast<expr_prop*>(this); break;
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case expr_kind::Type: static_cast<expr_type*>(this)->~expr_type(); delete[] reinterpret_cast<char*>(this); break;
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case expr_kind::Numeral: delete static_cast<expr_numeral*>(this); break;
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}
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}
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class eq_functor {
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expr_cell_pair_set m_eq_visited;
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public:
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bool apply(expr const & a, expr const & b) {
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if (eqp(a, b)) return true;
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if (a.hash() != b.hash()) return false;
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if (a.kind() != b.kind()) return false;
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if (is_var(a)) return get_var_idx(a) == get_var_idx(b);
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if (is_prop(a)) return true;
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if (is_shared(a) && is_shared(b)) {
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auto p = std::make_pair(a.raw(), b.raw());
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if (m_eq_visited.find(p) != m_eq_visited.end())
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return true;
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m_eq_visited.insert(p);
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}
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switch (a.kind()) {
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case expr_kind::Var: lean_unreachable(); return true;
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case expr_kind::Constant: return get_const_name(a) == get_const_name(b);
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case expr_kind::App:
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if (get_num_args(a) != get_num_args(b))
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return false;
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for (unsigned i = 0; i < get_num_args(a); i++)
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if (!apply(get_arg(a, i), get_arg(b, i)))
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return false;
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return true;
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case expr_kind::Lambda:
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case expr_kind::Pi:
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// Lambda and Pi
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// Remark: we ignore get_abs_name because we want alpha-equivalence
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return apply(get_abs_type(a), get_abs_type(b)) && apply(get_abs_expr(a), get_abs_expr(b));
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case expr_kind::Prop: lean_unreachable(); return true;
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case expr_kind::Type:
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if (get_ty_num_vars(a) != get_ty_num_vars(b))
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return false;
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for (unsigned i = 0; i < get_ty_num_vars(a); i++) {
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uvar v1 = get_ty_var(a, i);
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uvar v2 = get_ty_var(b, i);
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if (v1.first != v2.first || v1.second != v2.second)
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return false;
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}
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return true;
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case expr_kind::Numeral: return get_numeral(a) == get_numeral(b);
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}
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lean_unreachable();
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return false;
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}
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};
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bool operator==(expr const & a, expr const & b) {
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eq_functor f;
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return f.apply(a, b);
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}
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// Low-level pretty printer
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std::ostream & operator<<(std::ostream & out, expr const & a) {
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switch (a.kind()) {
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case expr_kind::Var: out << "#" << get_var_idx(a); break;
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case expr_kind::Constant: out << get_const_name(a); break;
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case expr_kind::App:
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out << "(";
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for (unsigned i = 0; i < get_num_args(a); i++) {
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if (i > 0) out << " ";
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out << get_arg(a, i);
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}
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out << ")";
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break;
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case expr_kind::Lambda: out << "(fun (" << get_abs_name(a) << " : " << get_abs_type(a) << ") " << get_abs_expr(a) << ")"; break;
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case expr_kind::Pi: out << "(pi (" << get_abs_name(a) << " : " << get_abs_type(a) << ") " << get_abs_expr(a) << ")"; break;
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case expr_kind::Prop: out << "Prop"; break;
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case expr_kind::Type: out << "Type"; break;
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case expr_kind::Numeral: out << get_numeral(a); break;
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}
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return out;
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}
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}
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