import sys
IS_PYTHON3 = sys.version_info[0] >= 3

if IS_PYTHON3:
    exec('from ._input import input as _input')
    exec('from ._parser import parser as _parser')
    exec('from ._lexer import lexer as _lexer')
else:
    exec('from _input import input as _input')
    exec('from _parser import parser as _parser')
    exec('from _lexer import lexer as _lexer')

class FortranRecordReader(object):
    '''
    Generate a reader object for FORTRAN format strings

    Typical use case ...

    >>> header_line = FortranRecordReader('(A15, A15, A15)')
    >>> header_line.read('              x              y              z')
    ['              x', '              y', '              z']
    >>> line = FortranRecordReader('(3F15.3)')
    >>> line.read('          1.000          0.000          0.500')
    [1.0, 0.0, 0.5]
    >>> line.read('          1.100          0.100          0.600')
    [1.1, 0.1, 0.6]

    Note: it is best to create a new object for each format, changing the format
    causes the parser to reevalute the format string which is costly in terms of
    performance
    '''
    
    def __init__(self, format):
        self.format = format
        self._eds = []
        self._rev_eds = []
        self._parse_format()

    def __eq__(self, other):
        if isinstance(other, FortranRecordReader):
            return self.format == other.format
        else:
            return object.__eq__(self, other)

    def match(self, record):
        try:
            self.read(record)
        except RecordError:
            return False
        else:
            return True

    def read(self, record):
        '''
        Pass a string representing a FORTRAN record to obtain the relevent
        values
        '''
        return _input(self._eds, self._rev_eds, record)

    def get_format(self):
        return self._format
    def set_format(self, format):
        self._format = format
        self._parse_format()
    format = property(get_format, set_format)

    def _parse_format(self):
        self._eds, self._rev_eds = _parser(_lexer(self.format))


if __name__ == '__main__':
    import doctest
    doctest.testmod()
