Hi Xavier,

Bisect_ppx does this by looking at the location of each module it sees in “structure". The file names are stored in a set. If a file name is not yet in the set, Bisect_ppx assumes that the module is the top-level module of a file. We haven’t had any problems with it.

You can see it here: https://github.com/aantron/bisect_ppx/blob/afa95d9f02ab4c95df3af283641c73ec1dc8cfb1/src/syntax/instrumentPpx.ml#L480

The code is a bit old, but there it is.

Best,

Anton

On Jun 17, 2016, at 12:10, Xavier Van de Woestyne <xavier@derniercri.io> wrote:

Hello, 

I have writted some ppx extension but I have a question, 

Is there a proper way to add a start "file" structure.

I have try using the "structure" member of the mapper : 

`

let new_mapper =

 Ast_mapper.{
   default_mapper with
   structure = general_structure
 }`

Where general_structure is just a

`my_begining_structure :: List.map (...)` but my begining 

structure is repeated into each module. It is logic but I need 

to add my own structure only at the begining of my file. In an 

other project, I use a mandatory attribute ([@@@active_this_ppx] 

for example), but imho, it is not a good approach. 

Thanks a lot for your feedback and advices ! 

Xavier Van de Woestyne

Développeur à Derniercri.io

http://derniercri.io