Re: var vs def

     Hello,

  The right side of the = is evaluated once and the result is stored for a
var, but for a def, it is evaluated again every time you call it.

  Also, vars don't take parameters (not even an empty ()), but defs can.

  A def is called a method and it is subject to overloading and overriding.

  A var is a field if it is in top-level of a trait/class/object, otherwise
it is a local variable.

     Best, Oliver

On Sat, May 2, 2015 at 6:57 AM, scalanewbie <[email protected]> wrote:

> Hello All,
>
> I am a newbie to scala and getting in grasp with val and def.
>
> I noticed that I could write :
>
> scala> var greatWorld2 = println("great world")
>
> great world
>
> greatWorld2: Unit = ()
>
>
> AND
>
>
> scala> def greatWorld() = println("great world")
>
> greatWorld: ()Unit
>
>
> Can someone please help me understand the difference?
>
>
> I am aware that var is generally used to define variables and def is used
> to define functions.
>
>
> Now, keeping in mind that greatWorld2 is actually a variable and not a
> function, I am trying to print it, and I get:
>
>
> scala> greatWorld2
>
>
> OR, if I try calling it as a function, it throws an error e.g. below
> (which sounds ok as I did not declare this as a function, so was expecting
> this anyway).
>
>
> scala> greatWorld2()
>
> <console>:9: error: Unit does not take parameters
>
>               greatWorld2()
>
>
>
>  Long story short, difference between var and def , in terms of what the
> interpreter and or compiler is doing underneath will be very good to
> understand.
>
>
> Thanks Guys,
>
> S
>
>
>
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-- 
Oliver Ruebenacker
Solutions Architect at Altisource Labs <http://www.altisourcelabs.com/>
Be always grateful, but never satisfied.

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