Re: [very beginner] function

Hi moonkid,

In "function x -> x*x", "x" is the name of the argument of the function.
It has a meaning inside the body of the function ("x*x"), but not
outside: the keyword "function" binds it.

For instance, "function y -> y*y" is exactly the same object: an
anonymous function taking an integer as un argument and computing its
square.

"(function x -> x * x) 5" defines this anonymous function and applies it
directly to "5", thus returning "25".

If you want to give a name to this function, you need to use the
let-binder, for instance:

# let f = function x -> x*x;;
# f 5;;

which is equivalent to the simpler:

# let f x = x*x;;
# f 5;;

This gives a name at top-level, which is re-usable anywhere else after
this point. You can also use a local name:

# let f = function x -> x*x in f 5;;

which is also equivalent to

# let f x = x*x in f 5;;

Hope this helps,
Chantal.



Le 03/11/2014 17:15, [email protected] [ocaml_beginners] a écrit :
> I understand this
> 
> # function x -> x*x ;;
> 
> But don't understand this
> 
> # (function x -> x * x) 5 ;;
> 
> It is a call of the function? Why do I have to put the complete
> function-definition again there?
> Isn't there a simpler way? Something like
> 
> # x (5) ;;
> - : int = 25
> 


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

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

Archives up to December 31, 2011 are also downloadable at http://www.connettivo.net/cntprojects/ocaml_beginners
The archives of the very official ocaml list (the seniors' one) can be found at http://caml.inria.fr
Attachments are banned and you're asked to be polite, avoid flames etc.
------------------------------------

Yahoo Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/ocaml_beginners/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/ocaml_beginners/join
    (Yahoo! ID required)

<*> To change settings via email:
    [email protected] 
    [email protected]

<*> To unsubscribe from this group, send an email to:
    [email protected]

<*> Your use of Yahoo Groups is subject to:
    https://info.yahoo.com/legal/us/yahoo/utos/terms/