Re: Scoping of procedure-level variables

[Adam Glauser <adamglauser@xxxxxxxxxxxx>]

> James Lampert wrote:
>> In ILE RPG, is the scope of procedure-level variables lexical or 
dynamic?

David Gibbs wrote:
> Pardon my denseness here ... but what does 'lexical' mean in this context?

I just glanced over the Wikipedia article "Scope (programming", because 
I was unsure as well.

If I'm following it correctly, you can think of it as compile-time 
(lexical) vs. run-time (dynamic) determination of scope.  I think I have 
an example of how this could make a difference in RPGLE.  James, please 
correct me if I'm wrong.  I'd also be interested to know what your use 
case is.

<pseudo code>
declare varName (integer)
call procB

procA
  declare varName (packed)
  call procB

procB
  varName = 3

</pseudo code>


If I'm understanding correctly, if the language in question uses lexical 
scoping then in the example above varName would be treated as an integer 
in both invocations, because the global scope is, as the Wikipedia 
article put it, the "nearest enclosing scope".

In a dynamically scoped language, the "mainline" invocation of procB 
would have varName treated as an integer, but when procA is invoked from 
procA, varName would be treated as packed.  In this case, the scope is 
determined by the most recent (re)definition of varName.