An object of this class contains the seven-character band number
prefix that is available to fill out the band number of any
n encounter line. For the format
of this line, see the
# - - - - - c l a s s P r e f i x - - - - - class Prefix: '''Represents one band number prefix line. Exports: Prefix(text): [ text is a string of exactly 7 characters -> return a new Prefix object with that text ] .text: [ as passed to constructor, read-only ] Prefix.scanLine(scan): # Static method [ scan is a Scan object -> just after a PREFIX_SYMBOL -> if (PREFIX_SYMBOL+the line in scan) is a valid band prefix line -> return a new Prefix object representing that line else -> Log() +:= error message(s) raise SyntaxError ] '''