I'd like to create a regular expression in Python that will match against a line in Python source code and return a list of function calls.
The typical line would look like this:
something = a.b.method(time.time(), var=1) + q.y(x.m())
and the result should be:
["a.b.method()", "time.time()", "q.y()", "x.m()"]
I have two problems here:
thank you for help
I don't think regular expressions is the best approach here. Consider the ast module instead, for example:
class ParseCall(ast.NodeVisitor):
def __init__(self):
self.ls = []
def visit_Attribute(self, node):
ast.NodeVisitor.generic_visit(self, node)
self.ls.append(node.attr)
def visit_Name(self, node):
self.ls.append(node.id)
class FindFuncs(ast.NodeVisitor):
def visit_Call(self, node):
p = ParseCall()
p.visit(node.func)
print ".".join(p.ls)
ast.NodeVisitor.generic_visit(self, node)
code = 'something = a.b.method(foo() + xtime.time(), var=1) + q.y(x.m())'
tree = ast.parse(code)
FindFuncs().visit(tree)
result
a.b.method
foo
xtime.time
q.y
x.m
ast module! Nice to know that it provides something a bit more useful than just literal_eval :)
$ python3
>>> import re
>>> from itertools import chain
>>> def fun(s, r):
... t = re.sub(r'\([^()]+\)', '()', s)
... m = re.findall(r'[\w.]+\(\)', t)
... t = re.sub(r'[\w.]+\(\)', '', t)
... if m==r:
... return
... for i in chain(m, fun(t, m)):
... yield i
...
>>> list(fun('something = a.b.method(time.time(), var=1) + q.y(x.m())', []))
['time.time()', 'x.m()', 'a.b.method()', 'q.y()']
/([.a-zA-Z]+)\(/g
should match the method names; you'd have to add the parens after since you have some nested.
foo("bar(a,b)") would return bar incorrectly for that regex.
I don't really know Python, but I can imagine that making this work properly involves some complications, eg:
But for your example, an expression like this works:
(?:\w+\.)+\w+\(
I have an example for you proving this is doable in Python3
import re
def parse_func_with_params(inp):
func_params_limiter = ","
func_current_param = func_params_adder = "\s*([a-z-A-Z]+)\s*"
try:
func_name = "([a-z-A-Z]+)\s*"
p = re.compile(func_name + "\(" + func_current_param + "\)")
print(p.match(inp).groups())
except:
while 1:
func_current_param += func_params_limiter + func_params_adder
try:
func_name = "([a-z-A-Z]+)\s*"
p = re.compile(func_name + "\(" + func_current_param + "\)")
print(p.match(inp).groups())
break
except:
pass
Command line Input: animalFunc(lion, tiger, giraffe, singe)
Output: ('animalFunc', 'lion', 'tiger', 'giraffe', 'singe')
As you see the function name is always the first in the list and the rest are the paramaters names passed
