Re: What's the reasoning behind z & s returning nular for empty input?

[Roman Perepelitsa <roman.perepelitsa@gmail.com>]

On Sat, Nov 9, 2019 at 9:11 AM Sebastian Gniazdowski
<sgniazdowski@gmail.com> wrote:
> Thanks for the analysis. The additional problem is that quoted but
> @-lacking s-flag should still elide the empty elements, as the manual
> states. So this is an intentional exception and I wonder why it has
> been added?

Here's the passage from zshexpn:

    For historical reasons, the usual behaviour that empty array
    elements are retained inside double quotes is disabled for arrays
    generated by splitting; hence the following:

        line="one::three"
        print -l "${(s.:.)line}"

    produces two lines of output for one and three and elides the
    empty field. To override this behaviour, supply the ‘(@)’ flag as
    well, i.e. "${(@s.:.)line}".

The phrase "for history reasons" is used to describe past design
decisions and/or implementations that would be different if the
benefit of hindsight were available at the time, but changing which is
infeasible due to the existing code relying on the current behavior.
In other words, the current behavior is unfortunate but cannot be
changed.


Roman.