How to check if a tool, partition, and variable are registered before envSetVal?

Hi Dan,

I think that 'envIsVal' is what you are looking for, e.g.

envIsVal("layoutXL" "autoArrange")
=> t
envIsVal("layoutXL" "autoOrange")
=> nil

You could potentially wrap this in a function or even in a macro. I hope that this helps!

Regards,

Lawrence

Here's my attempt at a macro for this called "envSetValSafe":

(defmacro envSetValSafe (tool var type val) `(when (envIsVal ,tool ,var) (envSetVal ,tool ,var ,type ,val)))
envSetValSafe("layout" "drawDottedGridOn" 'boolean t)
=> t
envSetValSafe("schematic" "madeItUp" 'boolean t)
=> nil
(expandMacro `(envSetValSafe "layoutXL" "autoArrange" 'boolean nil))
=> when(envIsVal("layoutXL" "autoArrange") 
    envSetVal("layoutXL" "autoArrange" 'boolean nil)
  )

You would still need to get the 'type' argument correct.

Regards,

Lawrence.

Lawrence (once an AE, always an AE ;-> ),

I should point out that there's no need for this to be a macro. A simple function would do - in general macros should only be used when you really need them (although this has conventional function call semantics). So it could have just been:

procedure(CCFenvSetValSafe(tool var type val)
  when(envIsVal(tool var)
    envSetVal(tool var type val)
  )
)

(good to have a prefix so that you know who to blame when something doesn't work). 

**Pedantry alert**. Let me give a slight convoluted reason as to why it wouldn't be a good idea to have this as a macro:

a="auto"
envSetValSafe("layoutXL" a=strcat(a "Arrange") 'boolean t)

This would expand to:

when((envIsVal "layoutXL"
    (a = strcat(a "Arrange"))
  )
  (envSetVal "layoutXL"
   (a = strcat(a "Arrange"))
   'boolean t
  )
)

so the variable you set wouldn't be the same as the variable you queried. I know this is fairly unlikely, but you have to be careful when you reference the same argument twice in a macro definition. The function version wouldn't have this side effect.

Regards,

Andrew