Peter Lewerin: I tried TclChecker on some of my longer programs today (2014-01-11). I'm not quite sure how I feel about it. TC didn't find very much to complain about, which I suppose could be because I'm just that good -- OTOH, it could mean that TC fails to detect anything beyond the most obvious blunders. So, what did it find?

1. I sometimes omit the default clause in a switch command. Yikes.
2. I sometimes omit -- before the string argument in a switch command. Oops. (TC did not complain about me omitting the -- in a regexp command, however, even when I used a variable dereference for the exp value.)
3. I usually omit the optional level argument to upvar.
4. I occasionally use constructs like set $varName foo or variable $varName foo, for instance when initializing a bunch of variables in one action, or append $varName foo if I need to select which variable to append to. TC doesn't like any of these, but is satisfied when I change $varName to [set varName].
5. A lot of undefined variables that actually were defined: TC doesn't seem to realize that variables get set by commands like regexp, catch, or dict with (OK, that last one is subtle).

(List roughly sorted in order of what I feel is justified to complain about.) 1 and 2: yes, those are valid points, I fixed those cases immediately and resolved to keep that in mind (even more than I already did) in the future (I was taught not to do #1 in the early 1980s, and have taught students of my own not to do it: I don't know why I still miss this sometimes). 3: Um, OK, maybe that's valid, even though I can't see myself passing in a variable name starting with a digit or a hash sign. 4: What's the problem, really? (Sure, sometimes it is a bug-causing mistake, and a serious one at that, but it wasn't in any of these cases.) I did make the change to [set varName] while negotiating with TC, but I don't think I'll change my ways in the future. 5: This is TC's problem, not mine. Unfortunately, short of inserting an excluding pragma or a set command there doesn't seem to be a way to arrange the source to avoid this false positive. I mean, if a variable really is undefined at the point of use, I will notice it not by running a checker, but by the program, you know, crashing.

Also, even though I specified version 8.6, TC didn't recognize the lmap command. Neither did it know about cmdline. It did check oo for some reason (I wasn't using OOP). Namespace ensembles seem to be a mystery to it.

I think I will test TC once more while actually creating a program (as opposed to trying it on working, more-or-less error-free programs). Maybe it will prove more useful in that situation.

In summary: if I were the manager of a team of programmers I'd insist on everyone using TC before checking in code because it would be good practice (a work environment is no place for idiosyncrasies or code that is even remotely dubious). For myself as a hobby programmer, I'm good if the program runs correctly (and I do test them at least informally, out of habit). While I suppose TC can sometimes be really helpful, it wasn't at this time: it mostly came dangerously close to just being a bother. I don't think I'm going to spend the money to get the license for it.