Feature request: ${(l[-3][0])var} to do left padding *without truncation*

[Stephane Chazelas <stephane@xxxxxxxxxxxx>]

At the moment:

$ set -o extendedglob
$ a=1-12-123-1234-12345
$ echo ${a//(#m)<->/${(l[3][0])MATCH}}
001-012-123-234-345

Numbers are "l"eft padded to a length of 3 with 0s, but also
truncated to 3 digits when longer. It's often not desired.

Same happens with -3 (though that doesn't seem to be documented):

$ echo ${a//(#m)<->/${(l[-3][0])MATCH}}
001-012-123-234-345

One can avoid the truncation with things like:

$ echo ${a//(#m)<->/${(l[$#MATCH > 3 ? $#match : 3][0])MATCH}}
001-012-123-1234-12345

Including wia a math function helper:

$ atleast() (( $#MATCH > $1 ? $#MATCH : $1 )); functions -M atleast
$ echo ${a//(#m)<->/${(l[atleast(3)][0])MATCH}}
001-012-123-1234-12345

But that's a bit cumbersome and needs to be adapted when the "m"
flag is also used..

Would it be possible to have a way to disable the truncating,
maybe via negative numbers where ${(l[3][0])var} would
pad-and-truncate as is currently does, but ${(l[-3][0])var}
would pad only (leave longer strings alone)?

Same for "r"ight-padding.

Or is there already a smarter way to do it than with my ternary
arithmetic expression above?

-- 
Stephane