jam shell

Hi,

I just had a thought.

I like the jam syntax and I thought it would be great to
replace our
unix shell by something similar to jam.

The main problem in the standard unix shell, I think, are
the weird
variable expansion rules that makes it difficult to write
shell scripts.
For example there is common bug, often shell scripts doesn't
handle
correctly filenames with spaces in them.

Does anyone here about a such shell ?

Mildred

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> I like the jam syntax and I thought it would be great
to replace our
> unix shell by something similar to jam.

You mean a shell with jam syntax, or... ?

> The main problem in the standard unix shell, I think,
are the weird
> variable expansion rules that makes it difficult to
write shell scripts.
> For example there is common bug, often shell scripts
doesn't handle
> correctly filenames with spaces in them.

This is not a bug, all shells works like this. The golden
rule of shell
scripting is that variables should be quoted, unless you
know what are
you doing. Differentiating between quoted and unquoted can
be called a
feature since with it can be accomplished very cool tricks.

For example (random thoughts), this would be very hard to
distinguish
for jam-like shell:

c = ls && pwd ;   # we want 'ls && pwd'
string or to execute each of them ?
c = "ls && pwd" ; # more shell like
behaviour, this is a string

--
Sanel
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The requirement for spaces before semicolons alone makes
this a poor
choice as a shell syntax.  (It almost disqualifies it as a
syntax
humans are allowed to touch... but we fix that by having an
svn
commit-hook that runs a "jamlint" tool that, among
other things, looks
for tokens with semicolons "in" them and reports
them as syntax errors
(and prevents the commit.)  It is unambiguous - it's just
different
enough from everything else that it's error-encouraging...)

(Yes, there are places where spaces matter in sh
conditionals too -
and they bite people, but it's already ubiquitous - it isn't
getting
displaced by something with *more* of that class of problem


On 3/30/07, Sanel Zukan <sanelzgmail.com> wrote:
> > I like the jam syntax and I thought it would be
great to replace our
> > unix shell by something similar to jam.
>
> You mean a shell with jam syntax, or... ?
>
> > The main problem in the standard unix shell, I
think, are the weird
> > variable expansion rules that makes it difficult
to write shell scripts.
> > For example there is common bug, often shell
scripts doesn't handle
> > correctly filenames with spaces in them.
>
> This is not a bug, all shells works like this. The
golden rule of shell
> scripting is that variables should be quoted, unless
you know what are
> you doing. Differentiating between quoted and unquoted
can be called a
> feature since with it can be accomplished very cool
tricks.
>
> For example (random thoughts), this would be very hard
to distinguish
> for jam-like shell:
>
> c = ls && pwd ;   # we want 'ls && pwd'
string or to execute each of them ?
> c = "ls && pwd" ; # more shell like
behaviour, this is a string
>
> --
> Sanel
> _______________________________________________
> jamming mailing list  -  jammingperforce.com
> http://maillist.perforce.com/mailman/listinfo/jamming
>


-- 
_Mark_ <eichinthok.org> <eichingmail.com>
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Hi,

technically speaking, the Rc shell doesn't have the Jam
syntax, but
it treats each value as a list of strings as well, which
makes for much
pleasant operations. Have a look, there's even a Unix port:

http://en.wikipedia.o
rg/wiki/Rc

Hope this helps,

- David


On Fri, 30 Mar 2007 02:19:16 +0200, "Mildred"
<ml.mildred593online.fr> said:
> Hi,
> 
> I just had a thought.
> 
> I like the jam syntax and I thought it would be great
to replace our
> unix shell by something similar to jam.
> 
> The main problem in the standard unix shell, I think,
are the weird
> variable expansion rules that makes it difficult to
write shell scripts.
> For example there is common bug, often shell scripts
doesn't handle
> correctly filenames with spaces in them.
> 
> Does anyone here about a such shell ?
> 
> Mildred
> 
> -- 
> Mildred       <xmpp:mildredjabber.fr> <http://mildred632.free
.fr/>
> Clef GPG :    <hkp://pgp.mit.edu> ou <http://mildred6
32.free.fr/gpg_key>
> Fingerprint : 197C A7E6 645B 4299 6D37 684B 6F9D A8D6
[9A7D 2E2B]
> _______________________________________________
> jamming mailing list  -  jammingperforce.com
> http://maillist.perforce.com/mailman/listinfo/jamming
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