Re: [9fans] mishandling empty lists - let's fix it

[sqweek <sqweek@gmail.com>]

2009/10/4 Sam Watkins <sam@nipl.net>:
> I wrote:
>> I don't see how this can be fixed in unix without breaking umpteen million
>> shell scripts.
>
> On Sun, Oct 04, 2009 at 06:12:15AM +0200, lucio@proxima.alt.za wrote:
>> By creating new commands with distinct new names.
>
> I thought of a better way.  We can fix the commands without breaking
> compatibility, using `--'.  `--' in unix normally excludes further options.

 It seems to me the obvious way to gain consistency is to do the list
parsing in one place only:

fn apply {
    cmd=$1
    shift
    while(! test $1 = :) {
        cmd=($cmd $1)
        shift
    }
    for(i in $*) $cmd <$i
}
# eg: apply grep foo : *.c

 Of course, this is likely to run you into other problems with the way
some programs want to use their arguments, which is why unix/plan 9
adopt the pragmatic approach.

 PS. excuse the test usage, feel free to point out the ~ idioms - if I
see them often enough they might stick in my memory :)
 PPS. i didn't actually check the semantics of for on an empty list,
maybe a conditional is required

-sqweek