create_sample_directory.py

#create_sample_directory.py - create some folders and files to demonstrate relative path includes

import os

os.mkdir("sample")
os.mkdir("sample/subfolder1")
os.mkdir("sample/subfolder2")

files = {
    "sample/a.txt": """\
I've got a lovely bunch of coconuts
#include subfolder1/b.txt
That's what the showman said
""",
    "sample/subfolder1/b.txt": """\
There they are, all standing in a row
#include ../subfolder2/c.txt
Give them a twist a flick of the wrist
""",
    "sample/subfolder2/c.txt": """\
Big ones, small ones, some as big as your head
"""
}

for filename, contents in files.items():
    with open(filename, "w") as file:
        file.write(contents)

main.py

#main.py - performs relative-path includes on files

import sys
import re
import os

def include(filename, seen=()):
    if filename in seen:
        raise Exception("Possible circular import:", next_filename)
    result = []
    curpath = os.path.abspath(os.path.split(filename)[0])
    with open(filename) as file:
        for line in file:
            if line.startswith("#include"):
                next_filename = re.match(r"\#include (.*)", line).group(1)
                next_filename = os.path.join(curpath, next_filename)
                result.append(include(next_filename, seen + (filename,)))
            else:
                result.append(line)
    return "".join(result)

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Please provide a filename.")
        sys.exit(0)
    filename = sys.argv[1]
    print(include(filename))

sample_usage.txt

c:\Users\Kevin\Desktop\import_project>create_sample_directory.py

c:\Users\Kevin\Desktop\import_project>main.py sample/a.txt
I've got a lovely bunch of coconuts
There they are, all standing in a row
Big ones, small ones, some as big as your head
Give them a twist a flick of the wrist
That's what the showman said