From mboxrd@z Thu Jan 1 00:00:00 1970 From: bakul at bitblocks.com (Bakul Shah) Date: Sun, 8 Jul 2018 16:27:54 -0700 Subject: [COFF] Other OSes? In-Reply-To: <20180708165006.21a7429e@jabberwock.cb.piermont.com> References: <20180705055650.GA2170@minnie.tuhs.org> <20180708165006.21a7429e@jabberwock.cb.piermont.com> Message-ID: On Jul 8, 2018, at 1:50 PM, Perry E. Metzger wrote: > > On Thu, 5 Jul 2018 15:56:50 +1000 Warren Toomey wrote: >> OK, I guess I'll be the one to start things going on the COFF list. >> >> What other features, ideas etc. were available in other operating >> systems which Unix should have picked up but didn't? >> >> [ Yes, I know, it's on-topic for TUHS but I doubt it will be for >> long! ] > > A minor feature that I might mention: TOPS-20 CMND JSYS style command > completion. TL;DR, this feature could now be implemented, as after > decades of wanting it I finally know how to do it in a unixy way. > > In TOPS-20, any time you were at the EXEC (the equivalent of the > shell), you could hit "?" and the thing would tell you what options > there were for the next thing you could type, and you could hit ESC to > complete the current thing. This was Very Very Nice, as flags and > options to programs were all easily discoverable and you had a handy > reminder mechanism when you forgot what you wanted. > > bash has some vague lame equivalents of this (it will complete > filenames if you hit tab etc.), and if you write special scripts you > can add domain knowledge into bash of particular programs to allow for > special application-specific completion, but overall it's kind of lame. > > Here's the Correct Way to implement this: have programs implement a > special flag that allows them to tell the shell how to do completion > for them! I got this idea from this feature being hacked in, in an ad > hoc way, into clang: > > http://blog.llvm.org/2017/09/clang-bash-better-auto-completion-is.html > > but it is apparent that with a bit of work, one could standardize such > a feature and allow nearly any program to provide the shell with such > information, which would be very cool. Best of all, it's still unixy > in spirit (IMHO). I believe autocompletion has been available for 20+ years. IIRC, I switched to zsh in 1995 and it has had autocompletion then. But you do have to teach zsh/bash how to autocomplete for a given program. For instance compctl -K listsysctls sysctl listsysctls() { set -A reply $(sysctl -AN ${1%.*}) } The compctl tells the shell what keyword list to use (lowercase k) or command to use to generate such a list (uppercase K). Then the command has to figure out how to generate such a list given a prefix. This sort of magic incantation is needed because no one has bothered to create a simple library for autocompletion & no standard convention has sprung up that a program can use. It is not entirely trivial but not difficult either. Cisco's CLI is a great model for this. It would even prompt you with a help string for non-keyword args such as ip address or host! With Ciscso CLI ^D to list choices, ^I to try auto complete and ? to provide context sensitive help. It was even better in that you can get away with just typing a unique prefix. No need to hit . Very handy for interactive use.