Re: a note on notations

[haahr@mv.us.adobe.com (Paul Haahr)]

> I believe that a redirection operator that opens for read and
> write is an excellent idea and definitely belongs in the shell.

i thought i'd said this definitively:  <> is going to mean redirect
both input and output.  to be consistent with the sh on my machine,
i'm going to have it require that the file exist and use fd 0 as
a default.  are there any suggestions (with good justification,
since i'm doing this largely for cultural compatility reasons) for
different semantics?

> the <>{ ... } syntax bites the big one.

everyone's agreed on that for a long time.  it's gone.  what will replace
is still a question.

> [John doesn't like :{} as es syntax, though it must be in dws' smiley book.]

fine, your arguments make sense.  again, for cultural compatibility, it's
perfectly reasonable to at least allowing : as null command.

[by the way, you mention using ': name; ' as a prompt, and cite the
bell labs folks.  i had done that too, for a while, and found it hard
to read through.  with the advent of rc, most of the plan 9 folks seem
to use 'name=; ' prompts.  i personally use the unadorned '; ' except
when running as root, when i use '!; ', but i generally don't hop from
machine to machine that much.]

> [ he doesn't like ${...} either ]

the overloading of $ is just too confusing and inconsistent.  i'm sorry
i sounded enthusiastic about it before.

> The syntax %{foo} was indirectly suggested.  This gets my vote.

it's probably getting my vote, too.  again, % will be a keyword like @,
so es %-named functions won't have to be quoted.  but, before i go off
and start hacking it in, i want opinions.  here are the possible characters,
based on what's not used yet, either by es or some other, major programs:

	% : , "

% is the most attractive alternative as far as i'm concerned.  any other
suggestions?

> es has already departed from the path of righteousness in making
> backslash special again (all in favour of rc's backslashes, shout AYE!);

i probably don't count, but NAY.  i use es' \ notations all the time.
it's one of es' major features as far as i'm concerned.  that it quotes
characters is really unimportant to me, but \n and \t, especially with
a terminal program that doesn't preserve tabs, are real wins.

paul