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scoping inside a block

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  scoping inside a block oldyork90 <oldyork90@yahoo.com> - 2011-12-27 12:08 -0800
    Re: scoping inside a block The Natural Philosopher <tnp@invalid.invalid> - 2011-12-27 21:06 +0000
    Re: scoping inside a block Gregor Kofler <usenet@gregorkofler.com> - 2012-01-09 14:31 +0100
      Re: scoping inside a block The Natural Philosopher <tnp@invalid.invalid> - 2012-01-09 14:49 +0000

#4148 — scoping inside a block

Is there a way to localize a var inside a block?  Can I have this
behavior without calling a function?


$myA = 'A'

{
     $myC = 'C';
     $myA = 'B';
     echo $myA . ' says B';
}

echo $myA . ' says A';
echo $myC   .... does not exist


Thank you.

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#4153

oldyork90 wrote:
> Is there a way to localize a var inside a block?  Can I have this
> behavior without calling a function?
> 
> 
> $myA = 'A'
> 
> {
>      $myC = 'C';
>      $myA = 'B';
>      echo $myA . ' says B';
> }
> 
> echo $myA . ' says A';
> echo $myC   .... does not exist
> 
> 
> Thank you.
yeah,. Write the program in C :-)

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#4352

Am 2011-12-27 21:08, schrieb oldyork90:
> Is there a way to localize a var inside a block?

No.

Gregor

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#4362

Gregor Kofler wrote:
> Am 2011-12-27 21:08, schrieb oldyork90:
>> Is there a way to localize a var inside a block?
> 
> No.
> 

Strictly, no. In practice, make that block a function?

The overhead on a call return is not great.
Even if its only ever used once.

There is a lot to be said for making any long bit of code into a series 
of calls to small functions  to improve isolation, and separate 
different logical flows.

So instead of if (this)
	{
	// Do pages of stuff...
	}
eslsee 	{
	// Do more pages of stuff
	}


becomes if (this)
	{
	Do_pages_of_stuff($withThis, $andThis..);
	}
else 	{
	Do_more_pages_of_stuff($withThis, $andThis..);
	}


etc etc.

I certainly find it helps me keep track of what the heck I am trying to 
do a bit easier anyway.


The other way is of course massive documentation and commenting as we 
used to do with Assembler, where the logical flow was completely 
obscured by the actual language statements.

A block statement at the top explaining the flow, and comments 
throughout  like
;*********************
; In this section we compare gross profit with gross interest on loans
; Register A is the loan, B is the profit, in pence.
;*******************************************************

CMP A,B ; 	If the net cash flow is equal to the interest
JMPLT NO_PROFIT ; THEN prepare shareholder excuses
	; 	ELSE etc ..


Which is megabytes of explanation for every few kilobytes of actual code..

The joy of discovering portable assembler AKA 'C' was...considerable.

Don't expect too much of your language: Just consider the alternatives....

> Gregor

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