ocaml-lib-devel

Re: [Ocaml-lib-devel] Re: Unzip module

[skaller <sk...@us...>]

On Sat, 2004-07-24 at 08:33, Brian Hurt wrote:

> Actually, I have a problem with doing this.  It's perfectly legal, but 
> that doesn't make it *right*.  

Sure its right! If you give your code a BSD licence
you expect the constraints to stick, and nothing more.
You've *deliberaly* allowed anyone to use the code
any way they want including modify it, refuse to
publish the changes, and indeed sell them.

I would argue NOT reusing that software would be 
the biggest 'sin' :)

-- 
John Skaller, mailto:sk...@us...
voice: 061-2-9660-0850, 
snail: PO BOX 401 Glebe NSW 2037 Australia
Checkout the Felix programming language http://felix.sf.net

Re: [Ocaml-lib-devel] Re: Unzip module

[skaller <sk...@us...>]

On Sat, 2004-07-24 at 09:12, skaller wrote:
> On Sat, 2004-07-24 at 08:33, Brian Hurt wrote:

> I would argue NOT reusing that software would be 
> the biggest 'sin' :)

BTW: Felix is 'FFAU', but about 1/3 of the physical
code is the Frontc/Cil C parser, which was produced
at Berkley (and naturally has a BSD licence).

Of course I emailed the authors and let them 
know I was using it, and naturally reported
a couple of bugs .. and asked some questions.

My code is freely available if they wish to
incorporate the changes I made into theirs
(which includes upgrading to C99 and some
weak C++ support).

I guess the authors are *happy* someone is
actually using their code. A lot of work went
into it. I would certainly like more people
to be using mine -- what's the point of writing
it otherwise?

I personally think it is only a matter of courtesy
to tell someone you're using their code, and to 
say 'thank you' -- hey, they might even add the
project to their own 'advocay' section, so it
benefts them.

And don't forget academics live on 'brownie points'
(citations) in the same way commercial entities
live on sales. Use that code -- you're doing them
a good turn!

-- 
John Skaller, mailto:sk...@us...
voice: 061-2-9660-0850, 
snail: PO BOX 401 Glebe NSW 2037 Australia
Checkout the Felix programming language http://felix.sf.net

Re: [Ocaml-lib-devel] Unzip module and filesystems

[Jere S. <xm...@xm...>]

On Fri, Jul 23, 2004 at 10:09:32PM +0200, Nicolas Cannasse wrote:
>The Unzip module is now part of ExtLib !
>You can deflate your TGZ and ZIP with pure OCaml code only !
>Enjoy,

Cool, thanks!

I've still to see your code in the CVS (does sourceforge always have a delay
after commit for the changes to show up?) but a few questions. So you have
unzip, how about a zip? It's always handy to pack stuff as well.

And how far does the current module go? Can it unpack whole zip files with
several files in them?

Which brings me to another curiosity I've been having. After looking at the
ocaml core library I was missing abstract files (so I could implement my
own, given an interface). Well, Extlib has that and great. But how about an
abstract filesystem? Something along the lines of:
---
class base_filesys :
	object
	method exists : string -> bool
	method size : string -> int

	method chdir : string -> unit
	method cwd : unit -> string
	end

class ['a] i_filesys :
	object
	inherit base_filesys

	method open_in : string -> 'a
	end

class ['a] o_filesys :
	object
	inherit base_filesys

	method delete : string -> unit

	method open_out : string -> 'a
	end

class ['a,'b] io_filesys :
	object
	inherit ['a] i_filesys
	inherit ['b] o_filesys
	end
---
That way you could do easy wrappings for filesystems. Useful things like:
 - Use a ZIP as a filesystem (input only if you please)
 - Use remote filesystem
 - Implement sandboxing (filesystem inside a filesystem, like prevent the
application accidentally accessing some part outside the given directory)

What do you guys think?

-- 
Jere Sanisalo [xm...@xm...] - http://www.xmunkki.org/

Re: [Ocaml-lib-devel] Unzip module and filesystems

[Sylvain LE G. <syl...@po...>]

Hello,

On Sat, Jul 24, 2004 at 02:01:29AM +0300, Jere Sanisalo wrote:
> On Fri, Jul 23, 2004 at 10:09:32PM +0200, Nicolas Cannasse wrote:
> >The Unzip module is now part of ExtLib !
> >You can deflate your TGZ and ZIP with pure OCaml code only !
> >Enjoy,
> 
> Cool, thanks!
> 
> I've still to see your code in the CVS (does sourceforge always have a delay
> after commit for the changes to show up?) but a few questions. So you have
> unzip, how about a zip? It's always handy to pack stuff as well.
> 
> And how far does the current module go? Can it unpack whole zip files with
> several files in them?
> 
> Which brings me to another curiosity I've been having. After looking at the
> ocaml core library I was missing abstract files (so I could implement my
> own, given an interface). Well, Extlib has that and great. But how about an
> abstract filesystem? Something along the lines of:
> ---
> class base_filesys :
> 	object
> 	method exists : string -> bool
> 	method size : string -> int
> 
> 	method chdir : string -> unit
> 	method cwd : unit -> string
> 	end
> 
> class ['a] i_filesys :
> 	object
> 	inherit base_filesys
> 
> 	method open_in : string -> 'a
> 	end
> 
> class ['a] o_filesys :
> 	object
> 	inherit base_filesys
> 
> 	method delete : string -> unit
> 
> 	method open_out : string -> 'a
> 	end
> 
> class ['a,'b] io_filesys :
> 	object
> 	inherit ['a] i_filesys
> 	inherit ['b] o_filesys
> 	end
> ---
> That way you could do easy wrappings for filesystems. Useful things like:
>  - Use a ZIP as a filesystem (input only if you please)
>  - Use remote filesystem
>  - Implement sandboxing (filesystem inside a filesystem, like prevent the
> application accidentally accessing some part outside the given directory)
> 

Well, i currently maintain a library which is called ocaml-fileutils. It
implements most operation you describe for real filesystem ( size = du,
exists = test Exist, cwd = pwd, delete = rm , in other word, take a look 
a the GNU fileutils ).

I was think of implementing a tar module for navigating tar archives,
and to give a model to expand it to anything else...

However, i don't use object oriented design ( i don't like this kind of
design )...

If you are interested in generating a tar navigator, please go ahead,
the library is made for extension ( if you want to extend, you will need
to use the module typing of the FileUtil module ).

Kind regard
Sylvain Le Gall

ps : http://www.carva.org/sylvain.le-gall/ocaml-fileutils.html

Re: [Ocaml-lib-devel] Unzip module and filesystems

[Nicolas C. <war...@fr...>]

> >The Unzip module is now part of ExtLib !
> >You can deflate your TGZ and ZIP with pure OCaml code only !
> >Enjoy,
>
> Cool, thanks!
>
> I've still to see your code in the CVS (does sourceforge always have a
delay
> after commit for the changes to show up?) but a few questions. So you have
> unzip, how about a zip? It's always handy to pack stuff as well.
>
> And how far does the current module go? Can it unpack whole zip files with
> several files in them?

Well. The current module is an implementation of the "deflate" algorithm
(zlib) conform to the RFC 1950 and 1951. Then you can unzip all kind of data
: png , swf , any gziped, zip, and a lot more. There is no direct support
for the ZIP or TGZ file format but I might add it pretty soon ( it's quite
easy once you can deflate :
http://www.pkware.com/products/enterprise/white_papers/appnote.txt ,
http://www.faqs.org/rfcs/rfc1952.html ,
http://www.onicos.com/staff/iz/formats/tar.html ).

As for "inflate", it's a bit more complicate : although it uses mostly same
data structures, you need to be careful to implement it in a patent-free way
(for american people, we european are not yet concerned about software
patents). I might try to do that later.

> Which brings me to another curiosity I've been having. After looking at
the
> ocaml core library I was missing abstract files (so I could implement my
> own, given an interface). Well, Extlib has that and great. But how about
an
> abstract filesystem? Something along the lines of:
[...]
> That way you could do easy wrappings for filesystems. Useful things like:
>  - Use a ZIP as a filesystem (input only if you please)
>  - Use remote filesystem
>  - Implement sandboxing (filesystem inside a filesystem, like prevent the
> application accidentally accessing some part outside the given directory)
>
> What do you guys think?

Well that's interesting idea.
Same problem as IO : we need to figure out what minimal support is needed so
adding a new filesystem is not too much a pain. Also, a module would be
better than classes.

Regards,
Nicolas Cannasse