how do I render Greek letters?

[AllenDowney]

Greek letters in math mode get parsed into MathSymbols. Each contains the corresponding unicode character in a class variable named unicode. For example (from Math.py):

class MathSymbol(Command):
    pass

# Lowercase
class alpha(MathSymbol): unicode = unichr(945)

After parsing, $\alpha$ appears as an alpha tag. Which is not great for me because I want to be able to check whether something is a MathSymbol without enumerating all possible MathSymbols.

Then, I want to write a template to generate the entity.

α

Something like

name: MathSymbol
type: python
'&#x%4x' % self.unicode

But again, MathSymbol doesn't appear at this point, only the specific tag (alpha, beta).

So, do I have to go back and change the way MathSymbols get parsed, or can I recover the information I need during TreeCleaning?

[tiarno]

not an answer, but maybe a helpful link for the issue later on: http://milde.users.sourceforge.net/LUCR/Math/

[AllenDowney]

Ok, I made some progress on this. In Math.py I've got class MathSymbol with this new invoke method:

def invoke(self, tex):
    a = Command.invoke(self, tex)
    print 'MathSymbol.invoke'
    print self, self.tagName, type(self)

    if self.unicode is None:
        return a
    if self.unicode == -1:
        code = self.tagName
    else:
        code = '&#x%04x;' % ord(self.unicode)

    o = self.ownerDocument.createElement('mathsymbol')
    child = self.ownerDocument.createTextNode(code)
    o.append(child)
    self.ownerDocument.context.push(o)
    return [o]

Seems to be working, although the ampersand is getting expanded. I might need to escape it.

Or maybe just put in the unicode character and let it get expanded?

[AllenDowney]

Groan. Well, this turns out to be easier than I made it out to be. It turns out that if you hoist any of the MathSymbols out of the math tag (which gets imaged) and into a mathphrase tag (which gets rendered) everything just works.