gen_readme.py

#!/usr/bin/env python3

def main():
    with open("README.md", "w") as out:
        with open("src/lib.md", "r") as f:
            lines = f.readlines()
        code_snippet = False
        for lineno, line in enumerate(lines, start=1):
            stripped = line.strip() + " "
            if code_snippet:
                if stripped.startswith("# "):
                    continue
                if stripped.startswith("##"):
                    before, __, after = line.partition("##")
                    line = "#".join((before, after))
                if stripped.startswith("```"):
                    code_snippet = False
            else:
                if stripped.startswith("```"):
                    for lang in ("rust", "toml"):
                        prefix = "```" + lang
                        if stripped.startswith(prefix):
                            prev, __, __ = line.partition(prefix)
                            out.write(f"\n{prev}<!-- AUTOGENERATED FILE -->\n\n")
                            line = "".join((prev, prefix, "\n"))
                            break
                    else:
                        raise RuntimeError("Unrecognized lang at line", lineno)
                    code_snippet = True
            out.write(line)


if __name__ == '__main__':
    main()