On 5/11/06, Axel Liljencrantz <[EMAIL PROTECTED]> wrote:
On 5/10/06, Philip Ganchev <[EMAIL PROTECTED]> wrote:
>
> Sorry, I was not clear. I did not mean anything about the "set"
> builtin. I was suggesting that
>
> foo[(seq 1 2)]
>
> should expand to
>
> foo[1 2]
>
> not to
>
> foo[1] foo[2]
>
> One way to achieve this is to make expansion work differently with
> brackets than with other strings. Currently,
First, perhaps just allowing quoted command substitution, a-la quoted
variable expansion, would be enough for this indexing issue:
set foo[1 "(seq 4 7)"] a b c d e
(Currently quoted parens are not expanded.)
I am uncomfortable with making command substitution tokenize
differently depending on whether we are in brackets or not. Introduces
far too much modality.
Perhaps it doesn't. It shouldn't be specifically command substitution.
We could define that content inside brackets is always parsed as a
nested command line: it is a space-separated list of words, with each word
possibly expanding to many words.
The effect that we want here is exaclty the joining (of word lists,
not concatenation of words) that happens in::
echo 1 (seq 4 7)
So we want a new way to apply such concatenation in a part of command line.
Properly designed, it could be a useful operator. We still have to decide what
is done with the result: ``foo[1 4 5 6 7]`` or ``foo[1] foo[4] foo[5]
foo[6] foo[7]``.
What I still don't like about this direction are the brackets. If
[...] become a
syntax for joining word lists, they shouldn't be left in the result --
if they are, it's
only useful for indexing.
Now, later in this thread you explain that all expansion in fish works as
outer products. For example::
echo %.(echo a\nb).(echo 1\n2)
echo {%,(echo a\nb),(echo 1\n2)},
prints::
%.a.1 %.a.2 %.b.1 %.b.2
%, a, 1, %, a, 2, %, b, 1, %, b, 2,
The first is obviously useful, for some of the examples you gave. The
second is questionable. Consider this equivallence::
echo {a,b},
set v a b; echo $v,
echo (echo a\nb),
All print ``a, b,``. But nesting them breaks the equivallance::
echo {%,{a,b},{1,2}},
set v a b; set n 1 2; echo {%,$v,$n},
echo {%,(echo a\nb),(echo 1\n2)},
print::
%, a, b, 1, 2,
%, a, 1, %, b, 1, %, a, 2, %, b, 2,
%, a, 1, %, a, 2, %, b, 1, %, b, 2,
This is strongly inconsistent and counter-intuitive!
I agree brace/command/variable expansions written side-by-side
(``%.$v.(seq 2)``)
should form an outer product, but inside braces, I think they should be joined,
just like ``{%,{a,b},{1,2}}`` produces ``% a b 1 2``.
What I'm driving at is that braces, not brackets, should be the
joining operator
that I talked about. And while at that, they should be space-separated like
everthing else in fish, not comma-separated. Yes, another incpatibility -- but
more consistent and easier to write.
--
Beni Cherniavsky <[EMAIL PROTECTED]>, who can only read email on weekends.
Governments are like kernels - everything possible should be done in user space.
