'tr' character class support?

[Rosen Penev]

On Fri, Jul 10, 2020 at 4:17 PM Jordan Geoghegan <jordan at geoghegan.ca> wrote:
>
>
>
> On 2020-07-10 14:54, Rosen Penev wrote:
> > On Fri, Jul 10, 2020 at 2:29 PM Jordan Geoghegan <jordan at geoghegan.ca> wrote:
> >>
> >>
> >> On 2020-07-10 14:15, Magnus Kroken wrote:
> >>> Hi Jordan
> >>>
> >>> On 10.07.2020 22:45, Jordan Geoghegan wrote:
> >>>> Hey folks,
> >>>>
> >>>> Does the 'tr' utility support character classes in OpenWRT? I was
> >>>> playing around with an OpenWRT x86_64 VM and I noticed that 'tr'
> >>>> doesn't seem to support character classes.
> >>>> The command " echo HELLO | tr '[:upper:]' '[:lower:]' "  does not
> >>>> convert to the text to lowercase as it should (and as required by
> >>>> POSIX).
> >>> This would be expected behavior. OpenWrt disables tr character classes
> >>> in BusyBox by default, see [1]:
> >>>
> >>> config BUSYBOX_DEFAULT_FEATURE_TR_CLASSES
> >>>          bool
> >>>          default n
> >>> config BUSYBOX_DEFAULT_FEATURE_TR_EQUIV
> >>>          bool
> >>>          default n
> >>>
> >>> I don't know what the size cost in the BusyBox binary is, but that
> >>> will likely be the deciding factor for such a change.
> >>>
> >>> 1:
> >>> https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=package/utils/busybox/Config-defaults.in
> >>>
> >>> Regards,
> >>> Magnus Kroken
> >> Hi Magnus,
> >>
> >> Thanks for confirming that so quickly.
> >>
> >> I obviously understand that space saving is essential to OpenWRT, but
> >> POSIX does require[1] that 'tr' support character classes:
> > awk '{print toupper($0)}' is an alternative.
> Yes, but this means that any script expecting tr to work correctly could
> explode, as tr silently ignores the character class and treats all the
> characters literally.
git grep upper | grep tr\ | wc -l
3

In the packages feed. All those results are things that run on the
host, not on OpenWrt.

tr a-z A-Z works as an alternative and is used in many places.
> >> :class:
> >>                Represents all characters belonging to the defined character class, as defined by the current setting of the LC_CTYPE  locale  cate-
> >>                gory. The following character class names shall be accepted when specified in string1:
> >>
> >>                  alnum    blank   digit   lower   punct   upper
> >>                  alpha    cntrl   graph   print   space   xdigit
> >>
> >>
> >> 1: https://www.unix.com/man-page/posix/1posix/tr/
> >>
> >>
> >> Regards,
> >> Jordan
> >>
> >>
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>