Regex expression of \S* is not recognized.

[gihanpanapitiya]

I am trying to create a custom parser to extract the boiling points from the following texts, so that the text between "boiling point" and "of" is optional.

Paragraph(u'The boiling point limit of 2,4,6-trinitrotoluene is 240 °C') # <- text 1
Paragraph(u'The boiling point of 2,4,6-trinitrotoluene is 240 °C') # <- text 2

I try to use the following prefix,

prefix = (I('boiling') + I('point') + Optional(R('^\S*$')).hide() + I('of') +\ R(r'\S+') +(I('is')|I('was')).hide() )(u'prefix').add_action(join)

But this fails for text2 when there is no text between "boiling point" and "of".

I am not sure whether this is related to the way the code is written.

Full code is given below.

from chemdataextractor.model import BaseModel, StringType, ListType, ModelType

class BoilingPoint(BaseModel):
    prefix = StringType()
    value = StringType()
    units = StringType()


Compound.boiling_points = ListType(ModelType(BoilingPoint))

import re
from chemdataextractor.parse import R, I, W, Optional, merge

prefix = (I('boiling') + I('point') + Optional(R('^\S*$')).hide() + I('of') +\
           R(r'\S+') +(I('is')|I('was')).hide() )(u'prefix').add_action(join)

units = (W(u'°') + Optional(R(u'^[CFK]\.?$')))(u'units').add_action(merge)
value = R(u'^\d+(\.\d+)?$')(u'value')
bp = (prefix + value + units)(u'bp')

from chemdataextractor.parse.base import BaseParser
from chemdataextractor.utils import first

class BpParser(BaseParser):
    root = bp

    def interpret(self, result, start, end):
        compound = Compound(
            boiling_points=[
                BoilingPoint(
                    prefix=first(result.xpath('./prefix/text()')),
                    value=first(result.xpath('./value/text()')),
                    units=first(result.xpath('./units/text()'))
                )
            ]
        )
        yield compound


Paragraph.parsers = [BpParser()]

d = Document(
    Heading(u'Synthesis of (3a)'),
#     Paragraph(u'The boiling point limit of 2,4,6-trinitrotoluene is 240 °C') # <- text 1
    Paragraph(u'The boiling point of 2,4,6-trinitrotoluene is 240 °C') # <- text 2
)

d.records.serialize()