CODEWITHSUNDEEP
ocaml
geckos
geckos

Reputation: 6279

oCaml '\n' = '\n' wont compile

I trying to compile a code and it gives me a non-sense error, I'm very new to oCaml so I'm missing something for sure

Here is the code

  let foo () =
    if '\n' = '\n' then begin
      print_endline "foo";
    end

Here is the error when I run dune build

File "gkoeditor.ml", line 46, characters 7-11:
46 |     if '\n' = '\n' then begin
            ^^^^
Error: This expression has type char but an expression was expected of type
         int

The whole source code can be found here https://github.com/dhilst/gkoeditor

I'm using Curses and Core libraries, for sure something is messing up with my environment,

Regards

Upvotes: 1

Views: 110

Answers (1)

Jeffrey Scofield
Jeffrey Scofield

Reputation: 66818

I believe that Core overrides the definition of = so that it is of type int -> int -> bool. The justification is that the polymorphic comparison sometimes causes problems. (It can cause an exception if the types contain functions, and can diverge in the presence of cyclic structures.)

Polymorphic = has never caused me any problems, and I find this redefinition to be a bit troubling for exactly the reason that it generates errors that seem to make no sense. However I can see the advantages.

At any rate, you can fix this by asking specifically for the polymorphic version of = in the Poly module.

Upvotes: 2

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