import sys

if sys.path[0] == '/usr/lib/python2.7/dist-packages':

    # nosetests puts this in

    sys.path = sys.path[1:]

from rdflib.term import _PLAIN_LITERAL_TYPES, _XSD_DOUBLE, _XSD_DECIMAL, Literal

from re import sub

def _literal_n3(self, use_plain=False, qname_callback=None):

    if use_plain and self.datatype in _PLAIN_LITERAL_TYPES:

        try:

            self.toPython() # check validity

            # this is a bit of a mess - 

            # in py >=2.6 the string.format function makes this easier

            # we try to produce "pretty" output

            if self.datatype == _XSD_DOUBLE:

                # this is the drewp fix

                return sub(r"\.?0*e","e", u'%e' % float(self))

            elif self.datatype == _XSD_DECIMAL:

                return sub("0*$","0",u'%f' % float(self))

            else:

                return u'%s' % self

        except ValueError:

            pass # if it's in, we let it out?

    encoded = self._quote_encode()

    datatype = self.datatype

    quoted_dt = None

    if datatype:

        if qname_callback:

            quoted_dt = qname_callback(datatype)

        if not quoted_dt:

            quoted_dt = "<%s>" % datatype

    language = self.language

    if language:

        if datatype:

            # TODO: this isn't valid RDF (it's datatype XOR language)

            return '%s@%s^^%s' % (encoded, language, quoted_dt)

        return '%s@%s' % (encoded, language)

    elif datatype:

        return '%s^^%s' % (encoded, quoted_dt)

    else:

        return '%s' % encoded

def patch():

    Literal._literal_n3 = _literal_n3

import unittest

class TestDoubleOutput(unittest.TestCase):

    def testNoDanglingPoint(self):

        vv = Literal("0.88", datatype=_XSD_DOUBLE)

        out = _literal_n3(vv, use_plain=True)

        print out

        self.assert_(out in ["8.8e-01", "0.88"], out)