A small script that prints function signatures based on ast.FunctionDef objects. Handles hint typing and defaults.

README.md

print_funcdefs.py

A small script that prints function signatures based on ast.FunctionDef objects. Handles hint typing and defaults.

Usage:

$ python print_funcdefs.py -h
usage: print_funcdefs.py [-h] [-v] file

Prints function signatures from a file (based on the AST representation).

positional arguments:
  file           The file to parse.

optional arguments:
  -h, --help     show this help message and exit
  -v, --verbose  Prints the dump of the FunctionDef object.
$ python print_funcdefs.py testpfd.py
square(x: int = 0) -> int
pow(x: int, p: int = 2) -> int
return_args(*args: int, **kwargs: Union[int, Tuple[int, ...]]) -> Dict[str, Union[int, Tuple[int, ...]]]

print_funcdefs.py

import ast, argparse

def get_value(node):
	if type(node)==ast.Name:
		return node.id
	if type(node)==ast.Num:
		return str(node.n)
	if type(node)==ast.Subscript:
		return get_value(node.value)+"["+get_value(node.slice)+"]"
	if type(node)==ast.Index:
		return get_value(node.value)
	if type(node)==ast.Tuple:
		return ", ".join(map(get_value,node.elts))
	if type(node)==ast.Ellipsis:
		return "..."
	if type(node)==ast.NameConstant:
		return str(node.value)
	if type(node)==ast.Attribute:
		return get_value(node.value)+"."+node.attr
	print(ast.dump(node))

class PrintFuncDefs(ast.NodeVisitor):
	VERBOSE = False
	def visit_FunctionDef(self,node):
		if self.VERBOSE: print("[VERBOSE]","FunctionDef object:",ast.dump(node))
		out=node.name+"("
		defs=len(node.args.args)-len(node.args.defaults)
		for n, arg in enumerate(node.args.args):
			out+=arg.arg
			if arg.annotation: out+=": "+get_value(arg.annotation)
			if n>=defs:
				out+=" = "+get_value(node.args.defaults[n-defs])
			out+=", "
		if node.args.vararg:
			out+="*"+node.args.vararg.arg
			if node.args.vararg.annotation: out+=": "+get_value(node.args.vararg.annotation)
			out+=", "
		if node.args.kwarg:
			out+="**"+node.args.kwarg.arg
			if node.args.kwarg.annotation: out+=": "+get_value(node.args.kwarg.annotation)
			out+=", "
		if node.args.kwonlyargs:
			if not node.args.vararg: out+="*, "
			for n,arg in enumerate(node.args.kwonlyargs):
				out+=arg.arg
				if arg.annotation: out+=": "+get_value(arg.annotation)
				if node.args.kw_defaults[n]: out+=" = "+get_value(node.args.kw_defaults[n])
				out+=", "
		out = (out[:-2] if (node.args.args or node.args.vararg or node.args.kwarg or node.args.kwonlyargs) else out)+")"
		if node.returns: out+=" -> "+get_value(node.returns)
		print(out)

if __name__=="__main__":
	parser = argparse.ArgumentParser(description="Prints function signatures from a file (based on the AST representation).")
	parser.add_argument("-v","--verbose",action="store_true",help="Prints the dump of the FunctionDef object.")
	parser.add_argument("file",help="The file to parse.")
	args = parser.parse_args()
	with open(args.file) as f:
		module = ast.parse(f.read())

	PrintFuncDefs.VERBOSE=args.verbose

	PrintFuncDefs().visit(module)

testpfd.py

from typing import Dict, Union, Tuple

def square(x: int = 0) -> int:
	return x**2

def pow(x: int,p: int = 2) -> int:
	return x**p

def return_args(*args: int,**kwargs: Union[int, Tuple[int, ...]]) -> Dict[str, Union[int, Tuple[int, ...]]]:
	kwargs["__args"] = args
	return kwargs