feat(util/name_map): add rename_map

src/util/CMakeLists.txt

@@ -4,6 +4,6 @@ add_library(util trace.cpp debug.cpp name.cpp name_set.cpp
   realpath.cpp script_state.cpp script_exception.cpp rb_map.cpp
   lua.cpp luaref.cpp lua_named_param.cpp stackinfo.cpp lean_path.cpp
   serializer.cpp lbool.cpp thread_script_state.cpp bitap_fuzzy_search.cpp
-  init_module.cpp thread.cpp memory_pool.cpp utf8.cpp)
+  init_module.cpp thread.cpp memory_pool.cpp utf8.cpp name_map.cpp)
 
 target_link_libraries(util ${LEAN_LIBS})

src/util/name_map.cpp

@@ -0,0 +1,17 @@
+/*
+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 "util/name_map.h"
+
+namespace lean {
+name const & rename_map::find(name const & k) const {
+    name const * it = &k;
+    while (name const * new_it = name_map<name>::find(*it)) {
+        it = new_it;
+    }
+    return *it;
+}
+}

src/util/name_map.h

@@ -9,4 +9,12 @@ Author: Leonardo de Moura
 #include "util/name.h"
 namespace lean {
 template<typename T> using name_map = rb_map<name, T, name_quick_cmp>;
+
+class rename_map : public name_map<name> {
+public:
+    // Similar to name_map::find, but it "follows" the sequence of renames.
+    // Example, if map contains "A->B" and "B->C", then find(A) returns C.
+    // Moreover, if k is not in the map, the result is \c k
+    name const & find(name const & k) const;
+};
 }