Stmdency

Stmdency, ST ate M ents depen DENCY, a tool handling python statements’ dependencies, can extract dependencies from Python statements according to the given statement identifier.

Installation

Stmdency can be installed from PyPI using pip:

python -m pip install --upgrade stmdency

Usage

Stmdency can be used as a Python module(as a command line tool will coming soon).

Extract Variable Dependencies

Let’s say we have a python code like below, we define a variable a and b and b depends on a:

a = 1
b = a + 2

Now we want to extract variable b and all of its dependencies, and we want to make sure our extracted code can be executed. Stmdency can help us to do this:

from stmdency.extractor import Extractor

statement = """
a = 1
b = a + 2
"""

extractor = Extractor(source=statement)
result = extractor.get_code("b")
print(result)

The result will be:

a = 1

b = a + 2

Extract Function Dependencies

Stmdency not only can extract variable dependencies, but also can extract function dependencies. Suppose we have the script below.

a = 1
b = 2

def bar():
    b = a + 3
    print(a, b)

def foo():
    bar(b)

Now we want to extract function foo and all of its dependencies, and we want to make our extracted code runnable.

from stmdency.extractor import Extractor

statement = """
a = 1
b = 2
def bar():
    b = a + 3
    print(a, b)
def foo():
    bar(b)
"""
extractor = Extractor(source=statement)
print(extractor.get_code("foo"))

The result will be:

a = 1

b = 2

def bar():
    b = a + 3
    print(a, b)

def foo():
    bar(b)

Python Code in File

As you can see, we use a string to represent the Python code in the above examples. But in most cases, our code is in a file. Stmdency can also handle this situation.

First, we need to create a file named test.py and write the code below into it:

cat <<EOF > test.py
a = 1
b = 2

def bar():
    b = a + 3
    print(a, b)

def foo():
    bar(b)
EOF

Then we can use the code below to extract function foo and all of its dependencies:

from stmdency.extractor import Extractor

with open("test.py", "r") as f:
    source = f.read()
    extractor = Extractor(source)
    print(extractor.get_code("foo"))