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wtd

Sat Jan 10, 2009 4:47 am


O'Caml TYS: many functions... one default

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Let's say I want to have a bunch of functions that take a default value.

let foo ?(bar = 42) () = bar * 3;;

let baz ?(wooble = 42) () = wooble / 2;;

Now, what if I want to change that default?  I'd have to edit the code in several places.

Figure out a way that I can change that default uniformly across both functions, without having to modify the functions themselves.  Storing the default as a separate let binding doesn't count.  ;-)


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sw2wolf

Fri Nov 18, 2011 10:42 pm


Re: O'Caml TYS: many functions... one default

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let defVal = 42

let foo ?(bar=defVal) () = bar *3


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wtd

Sat Nov 26, 2011 10:49 pm


RE:O\'Caml TYS: many functions... one default

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Good on you for trying, but I disqualified that approach in the original post.


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Aange10

Sat Nov 26, 2011 11:42 pm


RE:O\'Caml TYS: many functions... one default

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Oh come on wtd, it took two years for somebody to gut up and answer. Cut 'em some slack


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Tony

Sat Nov 26, 2011 11:59 pm


RE:O\'Caml TYS: many functions... one default

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can I use an inverse of a function? I.e., something like
[code]
let foo ?(bar = 42) () = bar * 3;; 

let baz ?(wooble = foo() / 3) () = wooble / 2;;
[/code]
:lol:


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wtd

Mon Nov 28, 2011 1:03 am


RE:O\'Caml TYS: many functions... one default

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[code]module X =
   functor (T : sig default : int end) ->
      struct 
         let foo () = T.default / 2
         let baz x = T.default * x
      end;;

let module Y = X(struct let default = 42 end) in
   Printf.printf "%d, %d\n" (Y.foo ()) (Y.baz 3);;[/code]