Creating one get/set method for a class

[Niels Henrik Bruun]

Hi

Was coding when I recalled this little hack which I would like to share with you.
In other programming languages you can have get and set in the same method as shown below.

. mata mata clear
. mata:
:     class demo
>     {
>         private:
>             real scalar value
>         public:
>             get_set_value()
>     }
:    
:         function demo::get_set_value(|real scalar value)
>         {
>             if (value == .) return(this.value)
>             else this.value = value
>         }
:    
:     d = demo()
:     // Set value
:     d.get_set_value(4)
:     // Get value
:     d.get_set_value()
  4
. end

[Sebastian Kripfganz]

Yes, that is essentially how many official Mata functions look like.

I prefer to code

if (args() == 0) return(this.value)

instead of

if (value == .) return(this.value)

[Ben Jann]

I agree with Sebastian, better use args(). Plus you can delete else, as this line will not be reached if the if condition is true.

[Niels Henrik Bruun]

Dear both I too use args() from time to time.
But that was not my point.
I wanted to show a method definition that did update a class property when given an argument and otherwise returned property content.