Type-ahead in unix
Alex Martelli
alex at am.sublink.org
Tue Apr 16 08:01:35 AEST 1991
torek at elf.ee.lbl.gov (Chris Torek) writes:
...
:True ... but deferred echo is not the way to do this. Deferred echo
:is even more broken than immediate echo. The *only* right thing is
:immediate-echo-unless-it-would-not-be-echoed-when-read followed by
:drag-user-echo-along-in-front-of-output. That is, if you type
...
:Now, if I had a GNOT, I would get `sliding echo-ahead' `for free',
:which solves most of the problem---password typeahead is very rare and
:`do not echo if future events would cause this not to be echoed' is an
:unreasonable demand. Or I could use Emacs, which almost gets it right
An IBM 3270 under VM/CMS almost "gets it right", too, most of the time:
the bottom two lines are used as an 'input pad' where you can (locally,
in the terminal/controller) edit one logical-line worth of "future
input" (with echo) - however, when you "Enter" this input, it goes to
the system, which 'stacks' it (without re-echoing it until it is
asked for - and the application can choose to explicitly 'flush' and
reject typed-ahead lines). The editing capability of the terminal and
controller is really too limited, one line is far too little, etc, but
I believe the "separate input pad" approach was later adopted and
generalized in Apollo workstations. I wouldn't mind, for many apps,
a variation of xterm that would give me a separate "input preparation"
text-editing widget (I know, I know, I can almost fake it with
xclipboard or whatever, and using selections, but...).
Yup, I know, GNOTs are far more elegant, but I surmise there are more
Apollos, X servers, and 3270s around (probably in increasing order of
abundance?) than GNOTs...
--
Alex Martelli - (home snailmail:) v. Barontini 27, 40138 Bologna, ITALIA
Email: (work:) martelli at cadlab.sublink.org, (home:) alex at am.sublink.org
Phone: (work:) ++39 (51) 371099, (home:) ++39 (51) 250434;
Fax: ++39 (51) 366964 (work only), Fidonet: 332/401.3 (home only).
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