[Caml-list] newbie problem with splitting code into files

[Caml-list] newbie problem with splitting code into files

[g.o.d]

Hello,

i am a bloody ocaml newbie. i have big problems with learning
ocaml as my brain refuses to thing functional... is get better slowly.

i studied several documentation sources but i was not able to find
a solution for the following problem:

i want to split code like for example the following into
several files:

-------------------- 8< --------------------
class type test_type = object
	val mutable x:int
	method get_x:int
end;;

class test : test_type = object
	val mutable x = 0
	method get_x = x
end;;

let main() =
	let t=new test in
	printf "X: %d\n" t#get_x;;

let _ = main()

-------------------- 8< --------------------

as long as i keep this in one file it works.
so what i did now is splitting it up, putting
class type declaration into test.mli, putting
class declaration into test.ml and putting
let main()... into main.ml

when i now compile test.mli followed by test.ml,
i get error messages like:

The implementation test.ml does not match the interface test.cmi:
The field `#test_type' is required but not provided
The field `test_type' is required but not provided

So what am i doing wrong?

thank you
-> Heiko Irrgang

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Re: [Caml-list] newbie problem with splitting code into files

[Xavier Leroy]

> i want to split code like for example the following into
> several files:

The following seems to do what you want:

----------- file test.mli -------------

class type test_type = object
        val mutable x:int
        method get_x:int
end
 
class test : test_type

----------- file test.ml --------------

class type test_type = object
        val mutable x:int
        method get_x:int
end
 
class test : test_type = object
        val mutable x = 0
        method get_x = x
end

----------- file main.ml --------------

open Test
open Printf

let main() = 
        let t=new test in
        printf "X: %d\n" t#get_x;; 
 
let _ = main()

---------------------------------------

Hope this helps,

- Xavier Leroy

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[Caml-list] Camlp4 for newbies

[TBraibant]

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This is a set of very basic questions about CamlP4.

Fisrt of all, is CAMLP4 really compatible with OCaml, because the Stream don't work the same way, in Ocaml, and particulary, the [<>] constructor don't work ...

Secondary, what are the main differences between CAMLP4, LEX, YACC? and where can i find a small tutorial about those ones?

Third of all, my own problem, is what is the efficientest and easiest way to implement a small compilator of a language of my own, under OCaml. I 'm currently using CamlP4, with a lot of evaluations formulas, like 

let instruction = parser | [< 'KEYWORD "Foo" >] -> Foo
;;

let operande = parser...;;
let modifier = parser...;;

Does someone know where i can find some examples of thing like that?

Thank you very much

Thomas Braibant









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Re: [Caml-list] newbie problem with splitting code into files

[Ken Rose]

g.o.d@zefix.tv wrote:
> 
> Hello,
> 
> i am a bloody ocaml newbie. i have big problems with learning
> ocaml as my brain refuses to thing functional... is get better slowly.

It took me a while, too.

> i studied several documentation sources but i was not able to find
> a solution for the following problem:

<snipped example>

> as long as i keep this in one file it works.
> so what i did now is splitting it up, putting
> class type declaration into test.mli, putting
> class declaration into test.ml and putting
> let main()... into main.ml
> 
> when i now compile test.mli followed by test.ml,
> i get error messages like:
> 
> The implementation test.ml does not match the interface test.cmi:
> The field `#test_type' is required but not provided
> The field `test_type' is required but not provided
> 
> So what am i doing wrong?

I haven't done anything with objects in ocaml, but when I see errors of
that sort, it means that the cmi file is stale and I need to do "make
clean; make".

That usually clears it up for me.

Good luck

 - ken

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