Generating pdf-latex with python script

I'm a college guy, and in my college, to present any kind of homework, it has to have a standard coverpage (with the college logo, course name, professor's name, my name and bla bla bla).

So, I have a .tex document, which generate my standard coverpages pdfs. It goes something like:

...
\begin{document}
%% College logo
\vspace{5cm}
\begin{center}
\textbf{\huge "School and Program Name" \\}
\vspace{1cm}
\textbf{\Large "Homework Title" \\}
\vspace{1cm}
\textbf{\Large "Course Name" \\}
\end{center}
\vspace{2.5cm}
\begin{flushright}
{\large "My name" }
\end{flushright}
...

So, I was wondering if there's a way to make a Python script that asks me for the title of my homework, the course name and the rest of the strings and use them to generate the coverpage. After that, it should compile the .tex and generate the pdf with the information given.

Any opinions, advice, snippet, library, is accepted.

Solution 1:

You can start by defining the template tex file as a string:

content = r'''\documentclass{article}
\begin{document}
...
\textbf{\huge %(school)s \\}
\vspace{1cm}
\textbf{\Large %(title)s \\}
...
\end{document}
'''

Next, use argparse to accept values for the course, title, name and school:

parser = argparse.ArgumentParser()
parser.add_argument('-c', '--course')
parser.add_argument('-t', '--title')
parser.add_argument('-n', '--name',) 
parser.add_argument('-s', '--school', default='My U')

A bit of string formatting is all it takes to stick the args into content:

args = parser.parse_args()
content%args.__dict__

After writing the content out to a file, cover.tex,

with open('cover.tex','w') as f:
    f.write(content%args.__dict__)

you could use subprocess to call pdflatex cover.tex.

proc = subprocess.Popen(['pdflatex', 'cover.tex'])
proc.communicate()

You could add an lpr command here too to add printing to the workflow.

Remove unneeded files:

os.unlink('cover.tex')
os.unlink('cover.log')

The script could then be called like this:

make_cover.py -c "Hardest Class Ever" -t "Theoretical Theory" -n Me

Putting it all together,

import argparse
import os
import subprocess

content = r'''\documentclass{article}
\begin{document}
... P \& B 
\textbf{\huge %(school)s \\}
\vspace{1cm}
\textbf{\Large %(title)s \\}
...
\end{document}
'''

parser = argparse.ArgumentParser()
parser.add_argument('-c', '--course')
parser.add_argument('-t', '--title')
parser.add_argument('-n', '--name',) 
parser.add_argument('-s', '--school', default='My U')

args = parser.parse_args()

with open('cover.tex','w') as f:
    f.write(content%args.__dict__)

cmd = ['pdflatex', '-interaction', 'nonstopmode', 'cover.tex']
proc = subprocess.Popen(cmd)
proc.communicate()

retcode = proc.returncode
if not retcode == 0:
    os.unlink('cover.pdf')
    raise ValueError('Error {} executing command: {}'.format(retcode, ' '.join(cmd))) 

os.unlink('cover.tex')
os.unlink('cover.log')

Solution 2:

There are of course templating systems like Jinja, but they're probably overkill for what you're asking. You can also format the page using RST and use that to generate LaTeX, but again that's probably overkill. Heck, auto-generating the page is probably overkill for the number of fields you've got to define, but since when did overkill stop us! :)

I've done something similar with Python's string formatting. Take your LaTeX document above and "tokenize" the file by placing %(placeholder_name1)s tokens into the document. For example, where you want your class name to go, use %(course_name)s

\textbf{\Large "%(homework_title)s" \\}
\vspace{1cm}
\textbf{\Large "%(course_name)s" \\}

Then, from Python, you can load in that template and format it as:

template = file('template.tex', 'r').read()
page = template % {'course_name' : 'Computer Science 500', 
                   'homework_title' : 'NP-Complete'}
file('result.tex', 'w').write(page)

If you want to find those tokens automatically, the following should do pretty well:

import sys
import re
import subprocess

template = file('template.tex', 'r').read()
pattern = re.compile('%\(([^}]+)\)[bcdeEfFgGnosxX%]')
tokens = pattern.findall(template)

token_values = dict()
for token in tokens:
    sys.stdout.write('Enter value for ' + token + ': ')
    token_values[token] = sys.stdin.readline().strip()

page = template % token_values
file('result.tex', 'w').write(page)

subprocess.call('pdflatex result.tex')

The code will iterate across the tokens and print a prompt to the console asking you for an input for each token. In the above example, you'll get two prompts (with example answers):

Enter value for homework_title: NP-Complete
Enter value for course_name: Computer Science 500

The final line calls pdflatex on the resulting file and generates a PDF from it. If you want to go further, you could also ask the user for an output file name or take it as an command line option.