Proposal for new operators to python that add syntactic sugar for hierarcical data.

[glomde]

i I would like to extend python so that you could create hiercical
tree structures (XML, HTML etc) easier and that resulting code would be
more readable than how you write today with packages like elementtree
and xist.
I dont want to replace the packages but the packages could be used with
the
new operators and the resulting IMHO is much more readable.

The syntax i would like is something like the below:

# Example creating html tree

'*!*' is an operator that creates an new node,
'*=*' is an operator that sets an attribute.

So if you take an example to build a smalle web page
and compare with how it looks with in element tree now
and how it would look like when the abover operators would exist.

With element tree package.

# build a tree structure
root = ET.Element("htm l")
head = ET.SubElement(r oot, "head")
title = ET.SubElement(h ead, "title")
title.text = "Page Title"
body = ET.SubElement(r oot, "body")
body.set("bgcol or", "#ffffff")
body.text = "Hello, World!"

With syntactical sugar:

# build a tree structure
root = ET.Element("htm l")
*!*root:
*!*head("head") :
*!*title("title ):
*=*text = "Page Title"
*!*body("body") :
*=*bgcolor = "#ffffff"
*=*text = "Hello, World!"

I think that with the added syntax you get better view of the html
page.
Repeating things dissapears and you get indentation that corresponds to
the tree.
I think it is very pythonic IMHO.

It could be done quite generic. If the variable, object after '*!*'
must support append
method and if you use '*=*' it must support __setitem__

Any comments?

[Bruno Desthuilliers]

Heiko Wundram a écrit :

Am Freitag 19 Mai 2006 02:08 schrieb Bruno Desthuilliers:

We'd need the make: statement, but the BDFL has pronounced against.

I'm still -2 against your proposition, but it could make a good use case
for the make statement. I gave an eye at the new 'with' statement, but
I'm not sure it could be used to solve this.

Couldn't. "with" is a blatant misnomer for that it's functionality is
(basically a "protected" generator), at least if you know what with does in
VB (god, am I really comparing VB with Python?

Lol !-)
And I've never even programmed
in the former...)

I did in a previous life. And believe me, this is kind of a WTF
language... To quote the poet : "Dumb all over, a little ugly on the side".

But I was not thinking about anything related to VB's 'with' !-)
Just about what other (than class) statements defines a block that then
becomes a namespace you can manipulate.

Something like:

with Node('root') as root:
with Node('head') as head:
with Node('title') as title:
title.content = "Page Title"
for s in section:
with Node('section %s' % s['title']) as section:
section.content = s['content']
Now the question is : how to we get the Node objects back ? If possible
without adding them explicitely to the parent object ? (which would not
solve the problem of the root Node anyway).

[glomde]

So I read trough all of the make PEP and make would support the syntax
i propose..
and more generic and better in many ways. Since it was rejected I have
to continue live
with my preprocessor...

From the make PEP

...... Allowing this sort of customization could allow XML to be written
without repeating element names, and with nesting of make-statements
corresponding to nesting of XML elements:

make Element html:
make Element body:
text('before first h1')
make Element h1:
attrib(style='f irst')
text('first h1')
tail('after first h1')
make Element h1:
attrib(style='s econd')
text('second h1')
tail('after second h1')

[Bruno Desthuilliers]

glomde a écrit :

So I read trough all of the make PEP and make would support the syntax
i propose..
and more generic and better in many ways. Since it was rejected I have
to

.... bug the BDFL until he reconsiders its position.

[Ian Bicking]

glomde wrote:

i I would like to extend python so that you could create hiercical
tree structures (XML, HTML etc) easier and that resulting code would be
more readable than how you write today with packages like elementtree
and xist.
I dont want to replace the packages but the packages could be used with
the
new operators and the resulting IMHO is much more readable.

You might want to look at PEP 359 for ideas:
http://www.python.org/dev/peps/pep-0359/

[bruno at modulix]

Ian Bicking wrote:

glomde wrote:

i I would like to extend python so that you could create hiercical
tree structures (XML, HTML etc) easier and that resulting code would be
more readable than how you write today with packages like elementtree
and xist.
I dont want to replace the packages but the packages could be used with
the
new operators and the resulting IMHO is much more readable.

You might want to look at PEP 359 for ideas:
http://www.python.org/dev/peps/pep-0359/

And more specifically here - this answers my doubts about the
possibility to use the with statement:

http://mail.python.org/pipermail/pyt...il/336774.html
--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'o****@xiludom. gro'.split('@')])"