Source to source for reduction clause - clang


I am new to clang and this problem may be so easy, but it took lots of my time. I am writing a source to source translator by clang for translating from my MetaFork language to OpenMP. I want to translate:

Why not change the token kind of “reduction”, “[”, … , “]” to tok::unknown? I suspect tok::comment might do something bad to your one-line “meta_for reduction[+: var] (int i=0; i<10; i++)”.