HHC 2022 - Programming Contest - no responses until after 6am Monday 6am CENTRAL

[3298]

No libraries at all sounds hard ... because quite a few built-in commands are from libraries!
For instance, HEAD and TAIL are commands 81 and 82 in library 171. Such builtin library commands make an unnecessary (in my opinion, anyway) minefield out of this challenge.

Conversely, flash pointers are no problem, right? :-) E.g. instead of CRLIB from L256 (deliberately showing a useless-for-this-purpose command to avoid giving hints) I could do #AD002h FLASHEVAL (which is called by CRLIB and implements its core functionality), it's just harder to understand, slightly slower, and significantly bigger (13 bytes for the binary integer + 2.5 bytes for the FLASHEVAL command; same size calculation applies to SYSEVAL and LIBEVAL, though the latter obviously calls libraries). I believe especially the latter should be enough of a penalty, considering the scoring criteria. For reference: a ROMPTR (i.e. library call) generated by the compiler takes 5.5 bytes, a FPTR 6 bytes, and a normal PTR takes the 2.5 bytes we all know about.

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Unrelated to the above: when I asked via PM, Gene confirmed that sample (C) showcases how you're supposed to start adding even if the input is already a palindrome. That is, the number of iterations shall only be 0. in the explicitly specified error conditions. I assumed that to be a mistake, but it is intentional.
That's actually nice, because DO ... UNTIL ... END is 2.5 bytes smaller than WHILE ... REPEAT ... END (assuming that flipping the condition is free, which it is in my program).