Source code for panvimwiki.filter.prefilter

"""Main function shared by prefilters."""

from __future__ import annotations

import fileinput
import re




def action(
    line: str, delete: str | None = None, replace: tuple[str, str] | None = None
) -> str | None:
    """Filter Vimwiki text by deleting lines or replacing text in lines.

    Parameters
    ----------
    line
        Line from Vimwiki file.

    delete
        Regex string matching all or part of line to be deleted.

    replace
        Regex re.search string and replacement string for re.sub.

    Returns
    -------
    str or None
        Convert line matching replace[0] regex by substituting replace[1].  To
        delete line matching delete regex, return None.  Otherwise return the
        original line. Replace precedes delete.

    """
    if replace is not None:
        re_search = re.compile(replace[0], re.MULTILINE)
        subst = replace[1]

        if re.search(re_search, line) is not None:
            return re.sub(re_search, subst, line, count=1)

    if delete is not None:
        re_delete = re.compile(delete, re.MULTILINE)

        if re.search(re_delete, line) is None:
            return line
        return None

    return line





def prefilter(
    delete: str | None = None, replace: tuple[str, str] | None = None
) -> None:
    """Read stdin, filter with action() to stdout.

    Parameters
    ----------
    delete
        Regex string matching all or part of line to be deleted.

    replace
        Regex re.search string and replacement string for re.sub.

    """
    with fileinput.input() as f:
        for line in f:
            lineout = action(line, delete, replace)
            if lineout is not None:
                print(lineout.rstrip("\n"))