ApplyLimitFunction in Packer

[Uight]

I would like to have a ApplyLimit function in the Packer to limit the values send to TxPack or limit the values received from RxUnpack.

The problem is that it is a bit unclear how you would implement this.
If both limits are 0 the limiter is anactive but i dont realy want to check for that everytime. i would like one of the following options:

1. property in the signal das is set when signal is created that is true if a valid limit is there.
2. we could set the limits to -inf and inf if no limit is set then we could always apply the limit (this is however a bit confusing as you would expect a parser to just show what was read in.)