Extend `ExprGenerator` with local and temporary variable support.
In the current implementation of the expression generator ExprGenerator
, both temporary and local variables can be requested, but they are not stored at all.
This extension stores the created variables in the generator so they can be copied to the PLC code afterwards.
In addition, temporary variables are not lost anymore after releasing them. The expression generator tracks availability for (re-)use, and prefers using already existing temporary variables above creating new ones.
Addresses #397 (closed)
Edited by Dennis Hendriks