there are a lot of design decisions that are pretty debatable, but the ones that seem clearly wrong to me are:
- indexing from 1 instead of 0;
- the absence of a nilness/nonexistence distinction (so misspelling a variable or .property silently gives the wrong answer instead of an exception);
- variables being global by default, rather than local by default or requiring an explicit declaration;
- printing tables by default (with %q for example) as identities rather than contents. (you could argue that this is a simplicity thing; lua 5.2 is under 15000 lines of code, which is pretty small for such a full-featured language, barely bigger than original-awk at 6200 lines of c and yacc plus 1500 lines of awk, and smaller than mawk at 16000 lines of c, 1100 lines of yacc, and 700 lines of awk. but a recursive table print function with a depth limit is about 25 lines of code.)
none of these are fatal flaws, but with the benefit of experience they all seem like clear mistakes
It's been long time since I last used lua and only positive memories remained :) I used it for adding scripting in the apps I worked on and the experience was very good -- sandboxed from the start, decent performance.
Perhaps having 0-based indexes would've been bad for our users but I don't think they used arrays at all.
