A simple Python routine to present a string in a banner-style box of asterisks

banner.py

def banner(text, width=40):
    """Print the received text in a banner-style box"""

    STARS = "".center(width, "*")
    BLANK = "{}{}{}".format("*", "".center(width - 2), "*", )
    usable_text_length = width - 4

    print()
    print(STARS)
    print(BLANK)

    # Remove extra spaces but NOT newlines, and split on remaining spaces.
    # This is to let the caller include line breaks.
    list_of_words = []
    for l in re.sub("  +", " ", text).split("\n"):
        line_as_list = l.split()
        list_of_words.extend(line_as_list)
        list_of_words.append("\n")

    # Initialise, then iterate over the list of words, preserving its
    # index value for later checking.
    line_length = 0
    line = ""
    for index, s in enumerate(list_of_words):

        # If the current word does not take us over the usable length,
        # append it to the current line. But first check for it being a
        # newline.
        if s == "\n":
            ready_to_print = True
        elif line_length + 1 + len(s) <= usable_text_length:

            # Handle the first word in a line differently from all the others
            line = line + s if line == "" else line + " " + s
            line_length = len(line)
            ready_to_print = False
        else:
            ready_to_print = True

        # If the above section completed a line; or if the current word is the
        # last one; or if the current line plus the NEXT word will take us
        # over the usable length; then print the line. Having printed,
        # reset the initial values.
        if (ready_to_print or
                index == len(list_of_words) - 1 or
                line_length + 1 + len(list_of_words[index + 1])
                > usable_text_length):
            print("* {} *".format(line.ljust(usable_text_length)))
            line_length = 0
            line = ""

    print(BLANK)
    print(STARS)
    print()