Re: special/readonly variables in sh emulation

[Bart Schaefer <schaefer@brasslantern.com>]

On Mon, 18 Mar 2002, Oliver Kiddle wrote:

> We perhaps ought to rethink the status of any special variables
> in sh emulation mode. Especially those which are autoloaded out of
> places like zsh/parameter. Any ideas on how to solve this?

My suggestion would be simply to disable module autoloading entirely when
in sh emulation mode (and maybe ksh too).  A sh/ksh script can't possibly
be expecting a dynamically loaded module, and "compinit" et al. can load
anything they explicitly need.

A slightly less drastic approach might be to disable autoloading only for
non-interactive sh emulation.

On Mon, 18 Mar 2002, Peter Stephenson wrote:

> Another is to shift this sort of parameter into a namespace, as we've
> been planning for a long time.  I think Sven had a way of doing this
> simply by allowing dots in parameter names --- it wasn't a fully
> featured namespace implementation, but it might be close enough to allow
> us to go over to that if anybody had the time to write it.

I've fooled around with this a bit.  The problem is that you have to allow
the dots only inside ${...}, because lots of things break if $file.ext is
interpreted as ${file.ext} rather than ${file}.ext.  This is a little
tricky to acheive, because there'd need to be different typtab[] flags for
lexing inside braces v. outside.

On Mon, 18 Mar 2002, Oliver Kiddle wrote:

> Compound variables could be implemented better by being like
> associative arrays - the parent is a hash table of the elements the
> only difference being the elements can be any type, and the syntax is
> different. This alone wouldn't be hard to add onto the existing
> parameter code.

In fact, I deliberately used full parameter hash tables for the
associative array implementation precisely so they could be extended in
the future to support elements of any type.  What's needed is a sensible
reference and assignment syntax.

> Also, am I right that we *need* a=() to assign an empty array?

No; `set -A a' will do it.