lean2/src/kernel/replace_visitor.cpp
Leonardo de Moura c1e451151a feat(replace_visitor): add an abstract class for applying transformations on expressions
I also removed replace_using_ctx since it is subsumed by the new class.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-23 15:01:37 -07:00

84 lines
3.3 KiB
C++

/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "kernel/replace_visitor.h"
namespace lean {
expr replace_visitor::visit_type(expr const & e, context const &) { lean_assert(is_type(e)); return e; }
expr replace_visitor::visit_value(expr const & e, context const &) { lean_assert(is_value(e)); return e; }
expr replace_visitor::visit_constant(expr const & e, context const &) { lean_assert(is_constant(e)); return e; }
expr replace_visitor::visit_var(expr const & e, context const &) { lean_assert(is_var(e)); return e; }
expr replace_visitor::visit_metavar(expr const & e, context const &) { lean_assert(is_metavar(e)); return e; }
expr replace_visitor::visit_app(expr const & e, context const & ctx) {
lean_assert(is_app(e));
return update_app(e, [&](expr const & c) { return visit(c, ctx); });
}
expr replace_visitor::visit_eq(expr const & e, context const & ctx) {
lean_assert(is_eq(e));
return update_eq(e, [&](expr const & l, expr const & r) { return std::make_pair(visit(l, ctx), visit(r, ctx)); });
}
expr replace_visitor::visit_abst(expr const & e, context const & ctx) {
lean_assert(is_abstraction(e));
return update_abst(e, [&](expr const & t, expr const & b) {
expr new_t = visit(t, ctx);
expr new_b;
{
cache::mk_scope sc(m_cache);
new_b = visit(b, extend(ctx, abst_name(e), new_t));
}
return std::make_pair(new_t, new_b);
});
}
expr replace_visitor::visit_lambda(expr const & e, context const & ctx) {
lean_assert(is_lambda(e));
return visit_abst(e, ctx);
}
expr replace_visitor::visit_pi(expr const & e, context const & ctx) {
lean_assert(is_pi(e));
return visit_abst(e, ctx);
}
expr replace_visitor::visit_let(expr const & e, context const & ctx) {
lean_assert(is_let(e));
return update_let(e, [&](expr const & t, expr const & v, expr const & b) {
expr new_t = t ? visit(t, ctx) : expr();
expr new_v = visit(v, ctx);
expr new_b;
{
cache::mk_scope sc(m_cache);
new_b = visit(b, extend(ctx, let_name(e), new_t, new_v));
}
return std::make_tuple(new_t, new_v, new_b);
});
}
expr replace_visitor::visit(expr const & e, context const & ctx) {
bool shared = false;
if (is_shared(e)) {
shared = true;
auto it = m_cache.find(e);
if (it != m_cache.end())
return it->second;
}
expr r;
switch (e.kind()) {
case expr_kind::Type: r = visit_type(e, ctx); break;
case expr_kind::Value: r = visit_value(e, ctx); break;
case expr_kind::Constant: r = visit_constant(e, ctx); break;
case expr_kind::Var: r = visit_var(e, ctx); break;
case expr_kind::MetaVar: r = visit_metavar(e, ctx); break;
case expr_kind::App: r = visit_app(e, ctx); break;
case expr_kind::Eq: r = visit_eq(e, ctx); break;
case expr_kind::Lambda: r = visit_lambda(e, ctx); break;
case expr_kind::Pi: r = visit_pi(e, ctx); break;
case expr_kind::Let: r = visit_let(e, ctx); break;
}
if (shared)
m_cache.insert(std::make_pair(e, r));
return r;
}
}