An object of this class contains the seven-character band
number prefix that is available to fill out the band number
of any following type n encounter line. For
the format of this line, see the specification.
# - - - - - 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 ]
"""