For rapidly changing business rules, I'm storing IronPython fragments in XML files. So far this has been working out well, but I'm starting to get to the point where I need more that just one-line expressions.
The problem is that XML and significant whilespace don't play well together. Before I abandon it for another language, I would like to know if IronPython has an alternative syntax.
IronPython doesn't have an alternate syntax. It's an implementation of Python, and Python uses significant indentation (all languages use significant whitespace, not sure why we talk about whitespace when it's only indentation that's unusual in the Python case).
I think you can set the xml:space="preserve" attribute or use a <![CDATA[ to avoid other issues, with for example quotes and greater equal signs.
Apart from the already mentioned CDATA sections, there's pindent.py which can, among others, fix broken indentation based on comments a la #end if - to quote the linked file:
When called as "pindent -r" it assumes its input is a Python program with block-closing comments but with its indentation messed up, and outputs a properly indented version.
...
A "block-closing comment" is a comment of the form '# end <keyword>' where is the keyword that opened the block. If the opening keyword is 'def' or 'class', the function or class name may be repeated in the block-closing comment as well. Here is an example of a program fully augmented with block-closing comments:
def foobar(a, b):
if a == b:
a = a+1
elif a < b:
b = b-1
if b > a: a = a-1
# end if
else:
print 'oops!'
# end if
# end def foobar
It's bundeled with CPython, but if IronPython doesn't have it, just grab it from the repository.
>>> from __future__ import braces
File "<stdin>", line 1
from __future__ import braces
^
SyntaxError: not a chance
All I want is something that will let my users write code like
Ummm... Don't do this. You don't actually want this. In the long run, this will cause endless little issues because you're trying to force too much content into an attribute.
Do this.
<Rule Name="Markup">
<Formula>(Account.PricingLevel + 1) * .05</Formula>
</Rule>
You should try not to have significant, meaningful stuff in attributes. As a general XML design policy, you should use tags and save attributes for names and ID's and the like. When you look at well-done XSD's and DTD's, you see that attributes are used minimally.
Having the body of the rule in a separate tag (not an attribute) saves much pain. And it allows a tool to provide correct CDATA sections. Use a tool like Altova's XML Spy to assure that your tags have space preserved properly.