239 lines
7.8 KiB
C++
239 lines
7.8 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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Soonho Kong
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*/
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#include <vector>
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#include <sstream>
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#include "expr.h"
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#include "free_vars.h"
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#include "sets.h"
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#include "hash.h"
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#include "format.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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expr_cell::expr_cell(expr_kind k, unsigned h):
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m_kind(static_cast<unsigned>(k)),
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m_flags(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):
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expr_cell(expr_kind::Constant, n.hash()),
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m_name(n) {}
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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 mk_app(unsigned n, expr const * as) {
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lean_assert(n > 1);
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unsigned new_n;
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unsigned n0 = 0;
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expr const & arg0 = as[0];
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// Remark: we represent ((app a b) c) as (app a b c)
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if (is_app(arg0)) {
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n0 = num_args(arg0);
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new_n = n + n0 - 1;
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} else {
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new_n = n;
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}
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char * mem = new char[sizeof(expr_app) + new_n*sizeof(expr)];
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expr r(new (mem) expr_app(new_n));
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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 (new_n != n) {
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for (; i < n0; i++)
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new (m_args+i) expr(arg(arg0, i));
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j++;
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}
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for (; i < new_n; ++i, ++j) {
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lean_assert(j < n);
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new (m_args+i) expr(as[j]);
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}
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to_app(r)->m_hash = hash_args(new_n, m_args);
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return r;
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}
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expr_eq::expr_eq(expr const & lhs, expr const & rhs):
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expr_cell(expr_kind::Eq, ::lean::hash(lhs.hash(), rhs.hash())),
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m_lhs(lhs),
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m_rhs(rhs) {
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}
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expr_eq::~expr_eq() {
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}
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expr_abstraction::expr_abstraction(expr_kind k, name const & n, expr const & t, expr const & b):
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expr_cell(k, ::lean::hash(t.hash(), b.hash())),
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m_name(n),
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m_domain(t),
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m_body(b) {
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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(level const & l):
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expr_cell(expr_kind::Type, l.hash()),
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m_level(l) {
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}
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expr_type::~expr_type() {
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}
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expr_let::expr_let(name const & n, expr const & v, expr const & b):
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expr_cell(expr_kind::Let, ::lean::hash(v.hash(), b.hash())),
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m_name(n),
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m_value(v),
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m_body(b) {
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}
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expr_let::~expr_let() {
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}
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expr_value::expr_value(value & v):
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expr_cell(expr_kind::Value, v.hash()),
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m_val(v) {
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m_val.inc_ref();
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}
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expr_value::~expr_value() {
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m_val.dec_ref();
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}
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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::Eq: delete static_cast<expr_eq*>(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::Type: delete static_cast<expr_type*>(this); break;
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case expr_kind::Value: delete static_cast<expr_value*>(this); break;
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case expr_kind::Let: delete static_cast<expr_let*>(this); break;
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}
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}
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expr mk_type() {
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static thread_local expr r = mk_type(level());
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return r;
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}
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class eq_fn {
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expr_cell_pair_set m_eq_visited;
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bool apply(expr const & a, expr const & b) {
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if (is_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 var_idx(a) == var_idx(b);
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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 const_name(a) == const_name(b);
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case expr_kind::App:
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if (num_args(a) != num_args(b))
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return false;
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for (unsigned i = 0; i < num_args(a); i++)
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if (!apply(arg(a, i), arg(b, i)))
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return false;
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return true;
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case expr_kind::Eq: return apply(eq_lhs(a), eq_lhs(b)) && apply(eq_rhs(a), eq_rhs(b));
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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(abst_domain(a), abst_domain(b)) && apply(abst_body(a), abst_body(b));
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case expr_kind::Type: return ty_level(a) == ty_level(b);
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case expr_kind::Value: return to_value(a) == to_value(b);
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case expr_kind::Let: return apply(let_value(a), let_value(b)) && apply(let_body(a), let_body(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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public:
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bool operator()(expr const & a, expr const & b) {
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return apply(a, b);
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}
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};
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bool operator==(expr const & a, expr const & b) {
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return eq_fn()(a, b);
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}
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bool is_arrow(expr const & t) {
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return is_pi(t) && !has_free_var(abst_body(t), 0);
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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 << "#" << var_idx(a); break;
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case expr_kind::Constant: out << 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 < num_args(a); i++) {
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if (i > 0) out << " ";
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out << arg(a, i);
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}
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out << ")";
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break;
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case expr_kind::Eq: out << "(" << eq_lhs(a) << " = " << eq_rhs(a) << ")"; break;
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case expr_kind::Lambda: out << "(fun " << abst_name(a) << " : " << abst_domain(a) << " => " << abst_body(a) << ")"; break;
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case expr_kind::Pi:
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if (!is_arrow(a)) {
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out << "(pi " << abst_name(a) << " : " << abst_domain(a) << ", " << abst_body(a) << ")";
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} else if (!is_arrow(abst_domain(a))) {
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out << abst_domain(a) << " -> " << abst_body(a);
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} else {
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out << "(" << abst_domain(a) << ") -> " << abst_body(a);
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}
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break;
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case expr_kind::Let: out << "(let " << let_name(a) << " := " << let_value(a) << " in " << let_body(a) << ")"; break;
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case expr_kind::Type: {
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level const & l = ty_level(a);
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if (l == level()) {
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out << "Type";
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} else {
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out << "(Type " << ty_level(a) << ")";
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}
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break;
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}
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case expr_kind::Value: to_value(a).display(out); break;
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}
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return out;
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}
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expr copy(expr const & a) {
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switch (a.kind()) {
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case expr_kind::Var: return mk_var(var_idx(a));
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case expr_kind::Constant: return mk_constant(const_name(a));
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case expr_kind::Type: return mk_type(ty_level(a));
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case expr_kind::Value: return mk_value(static_cast<expr_value*>(a.raw())->m_val);
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case expr_kind::App: return mk_app(num_args(a), begin_args(a));
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case expr_kind::Eq: return mk_eq(eq_lhs(a), eq_rhs(a));
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case expr_kind::Lambda: return mk_lambda(abst_name(a), abst_domain(a), abst_body(a));
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case expr_kind::Pi: return mk_pi(abst_name(a), abst_domain(a), abst_body(a));
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case expr_kind::Let: return mk_let(let_name(a), let_value(a), let_body(a));
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}
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lean_unreachable();
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return expr();
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}
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}
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void print(lean::expr const & a) { std::cout << a << "\n"; }
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