bug#29157: 25.3; Eshell parsing fails sometimes, e.g. "date" and "sed"

[Eli Zaretskii <eliz@gnu.org>]

> From: "John Wiegley" <johnw@gnu.org>
> Cc: Pierre Neidhardt <ambrevar@gmail.com>,  29157@debbugs.gnu.org,  npostavs@users.sourceforge.net
> Date: Sat, 25 Nov 2017 19:21:01 -0800
> 
> >>>>> "EZ" == Eli Zaretskii <eliz@gnu.org> writes:
> 
> EZ> Not just eshell/date: many Eshell built-ins behave like that, and they do
> EZ> that on purpose.
> 
> eshell/date is an alias for `current-time-string'. The fact that this Lisp
> function accepts arguments, and those arguments can be passed on the Eshell
> command-line, isn't something I thought of at the time.

Maybe not in this case, but other Eshell commands definitely feature
similar behaviors, and there you cannot convince me it's an accident,
because the behavior is documented in the doc string.

> In hindsight, a separate eshell/date function should have been created that
> would handle its arguments like the system command.

There is such a function: *date.