Remove Dash Conversion Of Smartypants Python Package

Originally Posted on with tags: web development / python / pelican
Last Update on

When I am working on the last post Git Command Reference, git commands often include an option such as git config --help. Bash commands often have two dashes -- before options. The python typogrify package (used in pelican) invokes smartypants package to convert -- into html en-dash —, and --- into em-dash –. However after checking the smartypants source code, I found that by default it actually only convert en-dash, not em-dash.

This is a case of code becoming too smart. I do not want two dashes -- to show up as en-dash. How to turn this feature off? Reading my previous post Typogrify Python Package, it is easy to create a new pelican plugin to remove this conversion.

Here are the code in mod_typogrify.py. 

from pelican import logger
from pelican import signals

from typogrify import filters

def init_mod_typogrify(sender):
    logger.debug('Init mod_typogrify Plugin')

def register():
    signals.initialized.connect(init_mod_typogrify)

    def smartypants(text):
        """Applies smarty pants to curl quotes.

        >>> smartypants('The "Green" man')
        'The “Green” man'
        """
        try:
            import smartypants
        except ImportError:
            raise TypogrifyError("Error in {% smartypants %} filter: ")
        else:
            from smartypants import Attr        #----- NEW
            attr = Attr.set1 & (~(Attr.mask_d)) #----- NEW
            output = smartypants.smartypants(text, attr) #--- add attr
            return output

    filters.smartypants = smartypants

I only added two lines and modified a line of smartypants function in typogrify to make it work. But figuring out how to create the correct attr took some time. Here is the bash session history when I am doing the experiment. 

(venv) george@X220:~/Code/georgexyz.com$ python
Python 3.9.2 (default, Mar 19 2021, 09:17:52) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from smartypants import Attr
>>> Attr.mask_d
56
>>> bin(Attr.mask_d)
'0b111000'
>>> bin(Attr.set1)  #---- default setting
'0b1001011'
>>> bin(Attr.set1 & (~(Attr.mask_d)))
'0b1000011'

Here is a test of -- and ---. They should show up as two dashes and three dashes instead of en-dash and em-dash.

This code change involves Python bitwise operators. Here is a link to Bitwise Operator on Python.org.

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