Declareing locals

[Otto]

Hello,
what is the right way to declare locals.

Should we assign a value directly when declaring a local.

For example:
Function test
local aTemp := {}
or is local aTemp enough.

Can someone please explain the difference.
Thank you in advance and best regards
Otto

[Enrico Maria Giordano]

This is a simple declaration:

local aTemp

while this other is a declaration with initialization:

local aTemp := {}

In the simple declaration the value of aTemp is NIL. After the initialization the type of aTemp is array and its value is an empty array.

EMG

[Otto]

Hello Enrico,
Thank you.
But what are the advantages and disadvantages of these two.
With kind regards
Otto

[Enrico Maria Giordano]

local aTemp := {}

is equivalent to

local aTemp
aTemp = {}

The advantage is that the first form is more compact, I presume.

EMG

[Otto]

Hello Enrico,
I read that declaration with initialization should be 3%-40% more speedy in executing the program.

Could this be?
Thank you in advance

Otto

[Enrico Maria Giordano]

Teoretically, yes. But I doubt it would make any visible difference in real programs.

EMG

[hmpaquito]

Mr. Otto,

Testing:

Code: Select all | Expand

FUNCTION Main()Local nILocal nMax:= 1000000Local nSec1, nSec2Local cSec1, cSec2nSec1:= Seconds()FOR nI:= 1 TO nMax   Local1()NEXTcSec1:= Str(Seconds()- nSec1, 10, 5)nSec2:= Seconds()FOR nI:= 1 TO nMax   Local2()NEXTcSec2:= Str(Seconds()- nSec2, 10, 5)MsgInfo("Mode 1: "+ cSec1+ Chr(13)+ Chr(13)+;             "Mode 2:"+ cSec2, "Results")RETURN NILSTATIC FUNCTION Local1()Local a:= {}RETURN NILSTATIC FUNCTION Local2()Local aa:= {}RETURN NIL 

[Enrico Maria Giordano]

This is NOT a real program, it is a sample. Anyway, it shows two identical values here.

EMG

[Otto]

Hello and thank you for your help.

I tested with these changes and see a difference in speed.

Code: Select all | Expand

RETURN NILLocal nMax:= 10000000 STATIC FUNCTION Local1()Local a:= {}Local b:= {}Local c:= {}Local d:= {}Local e:= {}Local c1:= ""Local c2:= ""Local c3:= ""Local c4:= ""Local c5:= "" 

Not much but there is a difference.
Best regards
Otto

[hmpaquito]

Mr. Otto,

Try first call to Local2() and after call to Local1()

Regards

[Otto]

Hello,
I did this yesterday and the results are the same. Declaration with initialization seams faster.
Enrico is right that in a real world program you would not see any differences.
In the same source I read that there is also speed differences between passing values by reference or value.
Best regards
Otto