List Commands Library for 50g

[John Keith]

(08-25-2017 09:07 PM)DavidM Wrote:  

(08-23-2017 12:00 PM)John Keith Wrote:  I can see the advantage of having the command be able to "massage" non-integer or out-of-range values but I believe that consistency across commands is more important.

This brings up an interesting consideration, and it's one that I haven't actually looked at in depth before.

For most commands that expect numbers that are implied integers as arguments (indices, counts, etc.), the ListExt code simply takes the integer part of the number if a real is provided.

I just checked a couple of built-in list commands (SUB and GET), and it looks like they both perform a rounding function on the arguments instead of taking the integer part (likely due to COERCE being used to convert those reals into System Binary Integers). For example:

Code:

{ 1 2 3 4 5 } 1.1 GET

returns 1

whereas

Code:

{ 1 2 3 4 5 } 1.8 GET

returns 2

SUB treats real arguments in a similar fashion to GET.

My personal feeling is that IP is more appropriate than rounding, but that makes the ListExt commands different than SUB and GET (and probably others, too).

I'm interested in seeing others' opinions on this. How should non-integer real numbers be treated when they are used to designate something that is intended to be an integer?

I had not noticed that behavior of SUB and GET myself. I agree that IP seems more "natural" than rounding but I also feel it is important that new commands work in a manner consistent with built-in ones.

John