asttokens module annotates Python abstract syntax trees (ASTs) with the positions of tokens
and text in the source code that generated them.
It makes it possible for tools that work with logical AST nodes to find the particular text that resulted in those nodes, for example for automated refactoring or highlighting.
asttokens is available on PyPI: https://pypi.python.org/pypi/asttokens/:
pip install asttokens
The code is on GitHub: https://github.com/gristlabs/asttokens.
The API Reference is here: http://asttokens.readthedocs.io/en/latest/api-index.html.
ASTTokens works with both Python2 and Python3.
Here’s an example:
import asttokens, ast source = "Robot('blue').walk(steps=10*n)" atok = asttokens.ASTTokens(source, parse=True)
Once the tree has been marked, nodes get
.last_token attributes, and
ASTTokens object offers helpful methods:
attr_node = next(n for n in ast.walk(atok.tree) if isinstance(n, ast.Attribute)) print(atok.get_text(attr_node)) start, end = attr_node.last_token.startpos, attr_node.last_token.endpos print(atok.text[:start] + 'RUN' + atok.text[end:])
Which produces this output:
ASTTokens object also offers methods to walk and search the list of tokens that make up
the code (or a particular AST node), which is more useful and powerful than dealing with the text
Tests are in the
tests/ subdirectory. To run all tests, run: