I would like to extract out the source code verbatim from code directives in a restructuredtext string.
What follows is my first attempt at doing this, but I would like to know if there is a better (i.e. more robust, or more general, or more direct) way of doing it.
Let's say I have the following rst text as a string in python:
s = '''
My title
========
Use this to square a number.
.. code:: python
def square(x):
return x**2
and here is some javascript too.
.. code:: javascript
foo = function() {
console.log('foo');
}
'''
To get the two code blocks, I could do
from docutils.core import publish_doctree
doctree = publish_doctree(s)
source_code = [child.astext() for child in doctree.children
if 'code' in child.attributes['classes']]
Now source_code is a list with just the verbatim source code from the two code blocks. I could also use the attributes attribute of child to find out the code types too, if necessary.
It does the job, but is there a better way?
Your solution will only find code blocks at the top level of a document, and it may return false positives if the class "code" is used on other elements (unlikely, but possible). I would also check the element/node's type, specified in its .tagname attribute.
There's a "traverse" method on nodes (and a document/doctree is just a special node) that does a full traversal of the document tree. It will look at all elements in a document and return only those that match a user-specified condition (a function that returns a boolean). Here's how:
def is_code_block(node):
return (node.tagname == 'literal_block'
and 'code' in node.attributes['classes'])
code_blocks = doctree.traverse(condition=is_code_block)
source_code = [block.astext() for block in code_blocks]