Excellent. Pablo, can you please send a PR with this? We'll then improve it there and I can help with setting up the tests. Please ask if you get stuck.
Ondrej On Wed, Jul 3, 2013 at 9:49 AM, Aaron Meurer <[email protected]> wrote: > Yes, definitely. Eventually, I would like to have a nice framework to > make parsing things like this easier and have a nicer, more extensible > API, but for now, I think even simple parsers like this are better > than nothing. > > Aaron Meurer > > On Wed, Jul 3, 2013 at 10:48 AM, Ondřej Čertík <[email protected]> > wrote: >> Pablo, >> >> On Wed, Jul 3, 2013 at 5:38 AM, peibol <[email protected]> wrote: >>> It will be something like that. For the moment, I'm just implemented the >>> basics of presentation mathml. I will add features as I need them. >>> >>> After running it, sympify should be called. What do you think about it? >>> >>> def parseMML(mmlinput): >>> from lxml import etree >>> from StringIO import * >>> from lxml import objectify >>> mmlinput= mmlinput.replace(' xmlns="', ' xmlnamespace="') >>> parser = etree.XMLParser(ns_clean=True,remove_pis=True,remove_comments=True) >>> tree = etree.parse(StringIO(mmlinput), parser) >>> objectify.deannotate(tree,cleanup_namespaces=True,xsi=True,xsi_nil=True) >>> mmlinput=etree.tostring(tree.getroot()) >>> exppy="" #this is the python expression >>> symvars=[] #these are symbolic variables which can eventually take part in >>> the expression >>> events = ("start", "end") >>> level = 0 >>> context = etree.iterparse(StringIO(mmlinput),events=events) >>> for action, elem in context: >>> if (action=='start') and (elem.tag=='mfrac'): >>> level += 1 >>> mmlaux=etree.tostring(elem[0]) >>> (a,b)=parseMML(mmlaux) >>> symvars.append(b) >>> exppy+=a >>> exppy+='/' >>> mmlaux=etree.tostring(elem[1]) >>> (a,b)=parseMML(mmlaux) >>> symvars.append(b) >>> exppy+=a >>> if (action=='end') and (elem.tag=='mfrac'): >>> level -= 1 >>> if level: >>> continue >>> if (action=='start') and (elem.tag=='mrow'): >>> exppy+='(' >>> if (action=='end') and (elem.tag=='mrow'): >>> exppy+=')' >>> if action=='start' and elem.tag=='mn': #this is a number >>> exppy+=elem.text >>> if action=='start' and elem.tag=='mi': #this is a variable >>> exppy+=elem.text >>> symvars.append(elem.text) #we'll return the variable, so sympy can sympify >>> it afterwards >>> if action=='start' and elem.tag=='mo': #this is a operation >>> exppy+=elem.text >>> return (exppy, symvars) >>> >>> >>> With the example: mmlinput='''<?xml version="1.0"?> <math >>> xmlns="http://www.w3.org/1998/Math/MathML"; >>> xmlns:mml="http://www.w3.org/1998/Math/MathML"; >>> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; >>> xsi:schemaLocation="http://www.w3.org/1998/Math/MathML >>> http://www.w3.org/Math/XMLSchema/mathml2/mathml2.xsd";> <mrow> <mfrac> <mrow> >>> <mn>3</mn> </mrow> <mrow> <mn>57</mn> </mrow> </mfrac> </mrow> </math>''' >>> >>> We get: >>> exppy='((3)/(57))' >> >> >> I think that's a great start. I assume you pass the expression to >> sympify() and obtain a SymPy expression as a result. >> >> Aaron, I think we should have this in sympy, what do you think? We can >> install lxml in .travis.yml and have this tested. If so, I can help >> you Pablo with sending a PR and get it setup. >> >> Ondrej >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/sympy. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > For more options, visit https://groups.google.com/groups/opt_out. > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. For more options, visit https://groups.google.com/groups/opt_out.
