The problem is me, probably, English is not my native tongue!

An OP is the structure used internally by perl to represent program code. By synthesize an OP I meant to artificially build and OP (in opposition to its natural birth at the perl parser).

And that means creating some OPs (maybe just one will do, I am not sure) using the newXXXOP functions, building a tree/sequence with them and setting up its internal state as if they had come from the parser.

But anyway, all this stuff would be far more complicated than just replicating the code for pp_vec.