CODEWITHSUNDEEP
pythonparsingindentationabstract-syntax-treestatic-analysis
finefoot
finefoot

Reputation: 11282

IndentationError during `ast.parse` and `ast.walk` of a function which is a method inside class

If I have a "regular" function, I can do ast.parse and ast.walk like this:

import ast
import inspect

def a():
    pass

code = inspect.getsource(a)
nodes = ast.walk(ast.parse(code))
for node in nodes:
    ...

However, if the function is a method inside a class like:

class B:
    def c(self):
        pass

code = inspect.getsource(B.c)
nodes = ast.walk(ast.parse(code))

I get:

IndentationError: unexpected indent

Which makes sense, I guess, since B.c is indented by one level. So how do I ast.parse and ast.walk here instead?

It seems like simply calling textwrap.dedent is not the right approach here, because it doesn't work if the code looks like this:

class B:
    def c(self):
        """
foo
"""
        pass

Upvotes: 2

Views: 3089

Answers (1)

Error - Syntactical Remorse
Error - Syntactical Remorse

Reputation: 7897

Its because you grabbed the method than tried walking it without undoing the indents. Your class is:

class B:
    def c(self):
        pass

code = inspect.getsource(B.c)
nodes = ast.walk(ast.parse(code))

If you print code you see:

    def c(self):
        pass

Note: The above code has one indent. You need to un-indent it:

import inspect
import ast
import textwrap
class B:
    def c(self):
        pass
code = textwrap.dedent(inspect.getsource(B.c))
nodes = ast.walk(ast.parse(code))

Upvotes: 11

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