Changeset 5d88a0a

Timestamp:

May 31, 2017, 4:33:21 PM (7 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

7b15d7a

Parents:

13932f14

Message:

Some more documentation for PassVisitor?

File:

• src/Common/PassVisitor.h (modified) (2 diffs)

src/Common/PassVisitor.h

@@ -6 +6 @@
 //Deep magic (a.k.a template meta programming) to make the templated visitor work
 //Basically the goal is to make 2 previsit_impl
-// 1 - 
+// 1 - Use when a pass implements a valid previsit. This uses overloading which means the any overload of 
+//     'pass.previsit( node )' that compiles will be used for that node for that type
+//     This requires that this option only compile for passes that actually define an appropriate visit.
+//     SFINAE will make sure the compilation errors in this function don't halt the build.
+//     See http://en.cppreference.com/w/cpp/language/sfinae for details on SFINAE
+// 2 - Since the first implementation might not be specilizable, the second implementation exists and does nothing.
+//     This is needed only to eliminate the need for passes to specify any kind of handlers.
+//     The second implementation only works because it has a lower priority. This is due to the bogus last parameter.
+//     The second implementation takes a long while the first takes an int. Since the caller always passes an literal 0
+//     the first implementation takes priority in regards to overloading.
 //-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 template<typename pass_type, typename node_type>
@@ -30 +39 @@
 
 //-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-//Templated visitor type
-
+// Templated visitor type
+// To use declare a PassVisitor< YOUR VISITOR TYPE >
+// The visitor type should specify the previsit/postvisit for types that are desired.
 //-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 template< typename pass_type >