IBP banding data system: Internal maintenance specification

Parses a variable-sized note number in a tail field. Although in theory banders are supposed to use only numbers here, again we are much more permissive: we'll accept any one or two characters neither of which are TAIL_CUE_CHAR.

The class attribute NOTE_PAT is a compiled regular expression that matches just that.

# - - -   B a s e E n c o u n t e r . t a i l N o t e   - - -

    NOTE_PAT = re.compile(r"[^%s]{1,2}" % TAIL_CUE_CHAR)

    def tailNote(self, scan):
        '''Parse a free-field note number.

          [ scan is a Scan object ->
              if scan starts with a note field ->
                scan  :=  scan advanced past that field
                self.(DISPOSITION_ATTR)  :=  a NoteField object
                    representing that field
              else ->
                Log()  +:=  error message(s)
                raise SyntaxError ]
        '''

        #-- 1 --
        # [ if scan starts with a string that matches self.NOTE_PAT ->
        #     scan  :=  scan advanced past that string
        #     s     :=  that string
        #  else ->
        #     Log()  +:=  error message(s)
        #     raise SyntaxError ]
        m = scan.tabReMatch(self.NOTE_PAT)
        if  m is None:
            scan.syntax("Expecting a note number.")
        else:
            s = m.group()

        #-- 2 --
        # [ self.(NOTE_ATTR)  :=  a new NoteField object with
        #                         value s ]
        setattr(self, NOTE_ATTR, NoteField(self, s))

You might ask, how come we can't use the .scanField() static method of the NoteField class? It's because note fields in the MAPS 2006 protocol are free-field, while they are fixed-field in the MAPS 2004 protocol. The NoteField.scanField() method works on a fixed-size field.