Use as a library

pyastgrep is structured internally to make it easy to use as a library as well as a CLI, with a clear separation of the different layers. For now, the following API is documented as public and we will strive to maintain backwards compatibility with it:

pyastgrep.api.search_python_files(paths, expression)

Searches for files with AST matching the given XPath expression, in the given paths.

If paths contains directories, then all Python files in that directory and below will be found, but .gitignore and other rules are used to ignore files and directories automatically.

Returns an iterable of Match object, plus other objects.

The other objects are used to indicate errors, usually things like a failure to parse a file that had a .py extension. The details of these other objects are not being documented yet, so use at own risk, and ensure that you filter the results by doing an isinstance check for the Match objects.

Parameters:

paths (list[pathlib.Path]) – List of paths to search, which can be files or directories, of type pathlib.Path
expression (str) – XPath expression

Returns:

Iterable[Match | Any]

class pyastgrep.api.Match

Represents a matched AST node. The public properties of this are:

property path

The path of the file containing the match.

Type:: pathlib.Path

property position

The position of the matched AST node within the Python file.

Type:: Position

property ast_node

The AST node object matched

Type:: ast.AST

property matching_line

The text of the whole line that matched

Type:: str

class pyastgrep.api.Position

property lineno

Line number, 1-indexed, as per AST module

Type:: int

property col_offset

Column offset, 0-indexed, as per AST module

Type:: int

For other things, we while we will try not to break things without good reason, at this point we are not documenting or guaranteeing API stability for these functions. Please contribute to the discussion if you have needs here.