generic graph (data structure) functions in Emacs?

generic graph (data structure) functions in Emacs?

[Ted Zlatanov]

Does Emacs have generic graph building and traversing libraries?  I
couldn't find anything.

I need these specifically for a n-child tree structure, which is easy
to do with nested lists, but I would prefer to use graph-oriented
algorithms.  I thought I'd check here before writing my own.

The reason is that the Gnus assistants need to lay out each assistant
screen as a graph node, with next/previous bidirectional edges between
them.  Right now, a simply n-child tree is enough, but I would like to
allow for the possibility of circular paths and multiple parents in
the assistant, which could be useful in the future.

Thanks
Ted

Re: generic graph (data structure) functions in Emacs?

[Ted Zlatanov]

On Fri, 11 Jun 2004, tzz@lifelogs.com wrote:

> Does Emacs have generic graph building and traversing libraries?  I
> couldn't find anything.
> 
> I need these specifically for a n-child tree structure, which is easy
> to do with nested lists, but I would prefer to use graph-oriented
> algorithms.  I thought I'd check here before writing my own.
> 
> The reason is that the Gnus assistants need to lay out each assistant
> screen as a graph node, with next/previous bidirectional edges between
> them.  Right now, a simply n-child tree is enough, but I would like to
> allow for the possibility of circular paths and multiple parents in
> the assistant, which could be useful in the future.

I'm really surprised there's nothing like this in Emacs already.  I'd
hate to reinvent the wheel, especially for something that seems like
a commonly needed library.

Ted

Re: generic graph (data structure) functions in Emacs?

[Paul Pogonyshev]

Ted Zlatanov wrote:
> On Fri, 11 Jun 2004, tzz@lifelogs.com wrote:
> 
> > Does Emacs have generic graph building and traversing libraries?  I
> > couldn't find anything.
> > 
> > I need these specifically for a n-child tree structure, which is easy
> > to do with nested lists, but I would prefer to use graph-oriented
> > algorithms.  I thought I'd check here before writing my own.
> > 
> > The reason is that the Gnus assistants need to lay out each assistant
> > screen as a graph node, with next/previous bidirectional edges between
> > them.  Right now, a simply n-child tree is enough, but I would like to
> > allow for the possibility of circular paths and multiple parents in
> > the assistant, which could be useful in the future.
> 
> I'm really surprised there's nothing like this in Emacs already.  I'd
> hate to reinvent the wheel, especially for something that seems like
> a commonly needed library.

AFAIK, Inge Wallin once wrote some generic data-structures library in
Elisp.  I guess it should turn up on googling.

Paul

Re: generic graph (data structure) functions in Emacs?

[Ted Zlatanov]

On Thu, 1 Jul 2004, pogonyshev@gmx.net wrote:

> AFAIK, Inge Wallin once wrote some generic data-structures library in
> Elisp.  I guess it should turn up on googling.

I found elib 1.0, which supports binary and AVL trees but not
graphs.  I contacted the elib maintainers to see if they were
interested in graphs.

Ted