[PATCH] Ash support for replace and subsitution

[Denys Vlasenko]

On Monday 24 March 2008 23:18, Paul Fox wrote:
>  > > What is the goal for ash? That I don't know.
>  > 
>  > From the practical point-of-view, bbox need standard-compliant shell.
>  > ash is (trying to be) such a shell. (Other two shells are far behind,
>  > but they are much smaller, and work on NOMMU!)
>  > 
>  > Above standard-compliance, bbox needs a shell which emulates bash.
>  > This is purely from practucal point-of-view: most Linux installations use
>  > bash as the primary shell => most scripts are written for bash
>  > (when they use non-standard bash-isms).
> 
> ubuntu has shown very successfully that /bin/sh _not_ be bash, so i
> think it's very possible to design most systems (esp.  embedded)
> not to need those features.

Ubuntu, basically, took the brunt of the effort to make
most package maintainers to stop using bashisms.
Which is no small task. I am grateful.

>  > Trivial bashism example: "function" keyword.
> 
> exactly.  trivial.  delete it.  :-)
> 
>  > Bashisms in ash can be guarded by ENABLE_FEATURE_BASH_COMPAT,
>  > in order to make standard lawyer-esque people happier.
> 
> if you're worried (and i know you are) that ash is already too big
> and complicated and bug-ridden, then i think we'd be well-served

Yes, sans "bug-ridden". I do not feel that ash is particularly buggy,
I think that it is too easy to MAKE it much more buggy by careless
changes because of its complexity.

> by limiting its feature set.  change "can" to "must" and i'll be
> happier.

I think that it's best to not dictate people what they want.

I want to avoid policy decisions like "ash will not implement
anything more than standard demands!". It's more like
"if you unset ASH_BASH_COMPAT, ash will lose support for most
non-standard bash extensions, and will be smaller".
--
vda