Generator for parsing text into fields such as command line arguments or raw CSV.

splitfields.py

def split_fields(text, delimiters = " \t\n\r", quotes = "\"'`"):
    """
    Field parsing generator; default parameters will function similar
    to command line argument parsing.
    
    Ex. >>> [f for f in split_fields("this   is\t`a te's't` ")]
        ['this', 'is', "a te's't"]
    """
    index = -1
    start = -1
    end = len(text) - 1
    in_quote = ""
    while index < end:
        index += 1
        char = text[index]
        if char in delimiters and not in_quote:
            if start >= 0:
                yield text[start:index]
                start = -1
        elif char in quotes:
            if start < 0:
                start = index
                in_quote = char
            elif char == in_quote:
                yield text[start+1:index]
                start = -1
                in_quote = ""
        elif start < 0:
            start = index
    if start >= 0:
        yield text[start:]

This was mostly an educational endeavor as the same could be done much more simply with a regular expression:

[m[0] if not m[1] else m[0][1:-1] for m in \
  re.findall(r"(([\"'`]).*?\2|[^\s\"'`]+)", "this   is\t`a te's't` ")]

But it's much less easy to read and possibly slower (I didn't bother speed testing mine vs. a regex method).