Can a constant be global?

Rob Cozens rcozens at pon.net
Mon Mar 27 10:28:32 EST 2006


David, Graham, et al:

> As far as I know, constants are only valid in the current script. 
> Globals are really "Global" but then they can't be initialized to a 
> value when they are defined, which is why I assume constants can't be 
> "Global".

There is little to be gained by declaring a constant as global, because 
both globals and constants must be declared in each script that 
references them.

Globals can be initialized:

	global twoPi
	put 2*3.1416 into twoPi

But they can also be changed by any handler at runtime.

> The only way I have found to make constants "Global" is to make and 
> use a Library Stack that becomes a sort of poor man's constant.

Note that this approach generates runtime activity, whereas a true 
constant is a compiler instruction that only comes into play at 
compilation.

What I do is declare all constants in the library:

	constant sdbConstant1= [constantValue]
	...
	...
	constant sdbConstantn= [constantValue]

Then I copy the declarations for those constants referenced in a 
specific script into that script.

	constant sdbConstant6= [constantValue]
	constant sdbConstant51= [constantValue]
	constant sdbConstant187= [constantValue]

Just what Graham is trying to avoid having to do.

Rob Cozens
CCW, Serendipity Software Company

"And I, which was two fooles, do so grow three;
Who are a little wise, the best fooles bee."

from "The Triple Foole" by John Donne (1572-1631)




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