List Commands Library for 50g

[DavidM]

(03-15-2018 08:21 PM)John Keith Wrote:  As far as I remember they were LFRST, which is just 1. SWAP SUB, and LPUSH, which is SWAP +. I'm at work now and don't have my notes available, but I'll check tonight if I have time.

John

I found an old PM where we were discussing a prior version of LFRST that was definitely slower than 1. SWAP SUB. That prior version was sharing some code with LLAST, and the overhead was getting in the way. The current version is completely independent, and essentially uses the same internal code as 1. SWAP SUB and performs the same or slightly better in the tests I just tried. LFRST does do one extra thing, though. It checks to see if the argument you give it is negative, in which case an error is generated. 1. SWAP SUB simply gives you an empty list for that kind of input.

LPUSH is actually the simplest command in the entire library. After checking the arguments (2: list, 1: anything), it executes a single SysRPL command: >HCOMP. It was faster than SWAP + in the couple of checks I just tried (though just by a very small amount). I believe I was inclined to keep that command as a logical partner to LPOP, even though in a program it consumes 5.5 bytes as opposed to SWAP + which only takes 5 bytes.

We also discussed LSEQ in those exchanges, which now has a significant speed advantage (as do the other sequence commands). And LNDUP, which no longer exists . LMRPT now does what LNDUP used to do, as well as its original stated purpose (repeating the contents of a list multiple times).

I'm pretty sure that was the discussion I was remembering. I'll stay on the lookout for others, though.