Sharing type definitions between different OCaml files

Question

Say A.ml B.ml C.ml D.ml all need to define some same types

type a = ... 
type b = ...

Since I don't want duplicate codes, I put these type definitions in a single file Shared_type.ml and I will do Open Shared_type in A.ml, B.ml ...

Is there a better and elegant way to handle this problem? Also, I feel like there might be something wrong with my underlying design. What are the possible improvements?

If you truly have common code that you want to open in every module (I don't believe what you intend is a case though), in 4.02.0 you can use the -open <module> command during compilation. — nlucaroni

Basile Starynkevitch Basile Starynkevitch · Accepted Answer · 2014-11-04T07:52:22

Yes you should put these declarations in a Shared.mli file containing only declarations, not definitions (you'll give definitions in Shared.ml). This is explained in §2.5 modules & seperate compilation

PS I strongly advise you to read entirely the ocaml manual before coding any serious thing in OCaml.

Sharing type definitions between different OCaml files

1 Answers