Eval function with variables

[tuna]

Hi, is it possible to use the eval function with variables e.g. Eval("foo + bar") or Eval("""The value of foo is "" & foo")?

This is because I have my database settings in a table (one field having the name of the setting and the other containing the value) and I wish to be able to reference variables in the settings value. E.g., for the "MsgOnExit" setting, I would have the string

"Are you sure you would like to exit " & AppTitle

Where AppTitle is the name of the database. I would then plan to use Eval at runtime to evaluate the expression to resolve AppTitle to a value. Of course, this may not be the best example as many would argue AppTitle should be a constant, but there are other settings which rely more heavily on variables being able to be resolved at runtime.

(I'm using a settings table because it allows for a settings GUI and also the ability to variables across sessions.)
​

Thanks

 

[namliam]

Msgbox "Are you sure you would like to exit " & AppTitle

will work without any eval what so ever.... so why use it

 

[tuna]

Thanks for your reply. It won't work because that's the literal string that will be stored in the settings table:

NAME      | VALUE
MsgOnExit | "Are you sure you would like to exit " & AppTitle

So really, I will end up with the string """Are you sure you would like to exit "" & AppTitle"

As I said, I'm doing this because I want to be able to reference variable in the settings value.

 

[namliam]

I would probably do something like:
replace ("Are you sure you would like to exit [AppTitle]", "[AppTitle]","program name")

To the best of my knowledge you cannot use eval for something like this

 

[tuna]

Thanks - but what about a setting like "var1 * var2"

 

[namliam]

Y = 5
Z = 10
Eval ( "Y * Z") << Will fail, because Eval requires functions...

Function y() As Integer
y = 5
End Function
Function Z() As Integer
Z = 10
End Function

eval("y() * z()")
50

Will work....

 

[tuna]

Hmmm. Ok, but what if I have >200 variables? Does this mean that I have to create >200 functions to call each variable?

Could I create just one function to reference variables dynamically? E.g.

Function VarGet(pVarName as String) As Variant
   'Code here - returns value of variable named according to the value of pVarName
End Function

Does VBA support dynamic variable references? I had wanted to create variable dynamically at runtime a while ago but was unable to do so. Thanks