Real KSH93 is finally free software!

Real KSH93 is finally free software!

[Juhapekka Tolvanen]

http://www.kornshell.com/
http://www.research.att.com/sw/download

They switched to Common Public License Version 1.0.

Now I just wonder: What features and abilities of KSH93 are still
missing from zsh? Is it possible to find useful KSH93-script that runs
fine under real KSH93 but not very well under zsh?

P.S: BTW also graphviz is free same way.


-- 
Juhapekka "naula" Tolvanen * http colon slash slash iki dot fi slash juhtolv
"Lennän taas. Olen juppihippipunkkari ja vaihdan paikkaa. Lennän taas. Turha
meikäläistä yrittääkään kategoriin laittaa. Hei mä lennän taas. Olen
juppihippipunkkari ja vaihdan paikkaa. Lennän taas."            Neljä Ruusua

Re: Real KSH93 is finally free software!

[Bart Schaefer]

On Apr 12,  8:12am, Juhapekka Tolvanen wrote:
}
} Now I just wonder: What features and abilities of KSH93 are still
} missing from zsh? Is it possible to find useful KSH93-script that runs
} fine under real KSH93 but not very well under zsh?

Sure; almost anything using namerefs or discipline functions.

Obviously, it's also possible to find useful zsh scripts that won't run
under ksh93.

Re: Real KSH93 is finally free software!

[Juhapekka Tolvanen]

Bart Schaefer <schaefer@brasslantern.com> writes:

> On Apr 12,  8:12am, Juhapekka Tolvanen wrote:
> }
> } Now I just wonder: What features and abilities of KSH93 are still
> } missing from zsh? Is it possible to find useful KSH93-script that runs
> } fine under real KSH93 but not very well under zsh?

> Sure; almost anything using namerefs or discipline functions.

Are them difficult or impossible to implement? If not, when they are
added to zsh?


-- 
Juhapekka "naula" Tolvanen * http colon slash slash iki dot fi slash juhtolv
"Lennän taas. Olen juppihippipunkkari ja vaihdan paikkaa. Lennän taas. Turha
meikäläistä yrittääkään kategoriin laittaa. Hei mä lennän taas. Olen
juppihippipunkkari ja vaihdan paikkaa. Lennän taas."            Neljä Ruusua

Re: Real KSH93 is finally free software!

[Peter Stephenson]

Juhapekka Tolvanen wrote:
> Bart Schaefer <schaefer@brasslantern.com> writes:
> 
> > On Apr 12,  8:12am, Juhapekka Tolvanen wrote:
> > }
> > } Now I just wonder: What features and abilities of KSH93 are still
> > } missing from zsh? Is it possible to find useful KSH93-script that runs
> > } fine under real KSH93 but not very well under zsh?
> 
> > Sure; almost anything using namerefs or discipline functions.
> 
> Are them difficult or impossible to implement? If not, when they are
> added to zsh?

I don't think they're particularly tricky, but they won't ever be added
unless someone specifically volunteers to write them.

pws


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Re: Real KSH93 is finally free software!

[Nikolai Weibull]

Peter Stephenson, April 12:

> > [namerefs]

> I don't think they're particularly tricky, but they won't ever be added
> unless someone specifically volunteers to write them.

I'd love namerefs.  I'll give it a try once I have time, say at the end
of the summer.  Until then,
        nikolai

-- 
Nikolai Weibull: now available free of charge at http://bitwi.se/!
Born in Chicago, IL USA; currently residing in Gothenburg, Sweden.
main(){printf(&linux["\021%six\012\0"],(linux)["have"]+"fun"-97);}

Re: Real KSH93 is finally free software!

[Bart Schaefer]

On Apr 12,  1:38pm, Peter Stephenson wrote:
}
} Juhapekka Tolvanen wrote:
} > Bart Schaefer <schaefer@brasslantern.com> writes:
} > 
} > > Sure; almost anything using namerefs or discipline functions.
} > 
} > Are them difficult or impossible to implement? If not, when they are
} > added to zsh?
} 
} I don't think they're particularly tricky

Actually they *are* particularly tricky, because of the way zsh's nested
parameter expansion passes data around.  Our first attempt to implement
namerefs was what led to ${(P)var}.

Discipline functions are ugly because in order to set them the parser has
to implement the other missing bit of ksh syntax, which is namespaces as
in ${foo.bar}.  Zsh doesn't allow "." as a valid character in variable
names and it's difficult to do so because the same identifier parser is
used both inside and outside the braces; that is, if you make the most
obvious change to enable ${foo.bar} then $foo.bar also parses as a single
variable name rather than as ${foo}.bar, which will break large numbers
of scripts.

So the changes to implement both of these things go fairly deep into the
most critical parts of the shell.

Re: Real KSH93 is finally free software!

[Oliver Kiddle]

Bart wrote:
> 
> Actually they *are* particularly tricky, because of the way zsh's nested
> parameter expansion passes data around.  Our first attempt to implement
> namerefs was what led to ${(P)var}.

For namerefs, the main job is cleaning up typeset code to not keep
disposing of parameters and recreating them anew. The typeset code is
also cluttered with special cases for handling special variables. So
some form of primitive typeset function needs to go in the _gsu struct.

> Discipline functions are ugly because in order to set them the parser has
> to implement the other missing bit of ksh syntax, which is namespaces as
> in ${foo.bar}.  Zsh doesn't allow "." as a valid character in variable

The ksh93 implementation of discipline functions doesn't cope well with
the fact that functions don't follow parameter scoping rules. So any
implementation of discipline functions may be better off using a
different design, incompatible with ksh.

Compound variables, namespaces and static scoping are higher on my
wishlist anyway.

Oliver

Re: Real KSH93 is finally free software!

[Bart Schaefer]

On Apr 12,  6:20pm, Oliver Kiddle wrote:
}
} The ksh93 implementation of discipline functions doesn't cope well
} with the fact that functions don't follow parameter scoping rules. So
} any implementation of discipline functions may be better off using a
} different design, incompatible with ksh.

That doesn't address the original question whether zsh can be capable of
executing any and all interesting ksh scripts.