Function _interpolate

web/db.py:1493–1560

Takes a format string and returns a list of 2-tuples of the form (boolean, string) where boolean says whether string should be evaled or not. from (public domain, Ka-Ping Yee)

(format)

def _interpolate(format):
    """
    Takes a format string and returns a list of 2-tuples of the form
    (boolean, string) where boolean says whether string should be evaled
    or not.

    from <http://lfw.org/python/Itpl.py> (public domain, Ka-Ping Yee)
    """

    def matchorfail(text, pos):
        match = tokenprog.match(text, pos)
        if match is None:
            raise _ItplError(text, pos)
        return match, match.end()

    namechars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_"
    chunks = []
    pos = 0

    while 1:
        dollar = format.find("$", pos)
        if dollar < 0:
            break
        nextchar = format[dollar + 1]

        if nextchar == "{":
            chunks.append((0, format[pos:dollar]))
            pos, level = dollar + 2, 1
            while level:
                match, pos = matchorfail(format, pos)
                tstart, tend = match.regs[3]
                token = format[tstart:tend]
                if token == "{":
                    level = level + 1
                elif token == "}":
                    level = level - 1
            chunks.append((1, format[dollar + 2 : pos - 1]))

        elif nextchar in namechars:
            chunks.append((0, format[pos:dollar]))
            match, pos = matchorfail(format, dollar + 1)
            while pos < len(format):
                if (
                    format[pos] == "."
                    and pos + 1 < len(format)
                    and format[pos + 1] in namechars
                ):
                    match, pos = matchorfail(format, pos + 1)
                elif format[pos] in "([":
                    pos, level = pos + 1, 1
                    while level:
                        match, pos = matchorfail(format, pos)
                        tstart, tend = match.regs[3]
                        token = format[tstart:tend]
                        if token[0] in "([":
                            level = level + 1
                        elif token[0] in ")]":
                            level = level - 1