Exists:
 
Foo
Foo::Bar
Foo::Bar::Baz
Foo::Baz::Bat
Foo::Baz::Bat::Bam
 
Examples:
 
Foo.full_const_get("Bar") #=> Foo::Bar
Foo::Baz.full_const_get("Bar::Baz") #=> Foo::Bar::Baz
Foo::Baz::Bat.full_const_get("Bar::Baz") #=> Foo::Bar::Baz
 
Algorithm:
 
do regular const_get, then do the rigid const_get from Merb. Failing that, try to do the rigid const_get for the first two, etc.