extweave.icn: Program to extract weaving specifications from weave file

This program extracts the weaving specifications from a Macintosh
Painter 5 weave file in MacBinary format.  (It might work on Painter 4
weave files; this has not been tested.)

The file is read from standard input.

The output consists of seven lines for each weaving specification in the
file:

     wave name
     warp expression
     warp color expression
     weft expression
     weft color expression
     tie-up
     blank separator

The tie-up is a 64-character string of 1s and 0s in column order. That
is, the first 8 character represent the first column of the tie-up. A
1 indicates selection, 0, non-selection.

This program does not produce the colors for the letters in color
expressions.  We know where they are located but haven't yet figured
out how to match letters to colors.

See Advanced Weaving, a PDF file on the Painter 5 CD-ROM.