412eea1dbf
timex is a datetime processing library allowing you to write time expressions in a DLS as strings. Splitting this out from Winchester as a separate library, since it could be useful elsewhere.
103 lines
2.8 KiB
Python
103 lines
2.8 KiB
Python
import sys
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import logging
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import ply.lex
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from timex.expression import TimexLexerError
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logger = logging.getLogger(__name__)
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class TimexLexer(object):
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"""Lexing/tokenising for time expressions"""
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def __init__(self, debug=False):
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self.debug = debug
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if not self.__doc__:
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raise TimexLexerError("Docstring information is missing. "
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"Timex uses PLY which requires docstrings for "
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"configuration.")
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self.lexer = ply.lex.lex(module=self,
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debug=self.debug,
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errorlog=logger)
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self.lexer.string_value = None
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self.latest_newline = 0
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def input(self, string):
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self.lexer.input(string)
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def token(self):
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token = self.lexer.token()
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if token is None:
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if self.lexer.string_value is not None:
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raise TimexLexerError("Unexpected EOF in expression")
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else:
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token.col = token.lexpos - self.latest_newline
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return token
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reserved_words = { 'to' : 'TO',
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'us' : 'MICROSECOND',
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's' : 'SECOND',
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'sec' : 'SECOND',
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'm' : 'MINUTE',
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'min' : 'MINUTE',
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'h' : 'HOUR',
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'hr' : 'HOUR',
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'd' : 'DAY',
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'mo' : 'MONTH',
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'y' : 'YEAR',
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'yr' : 'YEAR',
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}
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tokens = ('NUMBER',
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'PLUS',
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'MINUS',
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'REPLACE',
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'RPAREN',
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'LPAREN',
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'VAR',
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'IDENTIFIER') + tuple(set(reserved_words.values()))
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t_PLUS = r'\+'
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t_MINUS = r'-'
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t_REPLACE = r'@'
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t_VAR = r'\$'
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t_LPAREN = r'\('
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t_RPAREN = r'\)'
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def t_IDENTIFIER(self, t):
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r'[a-zA-Z_][a-zA-Z0-9_]*'
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t.type = self.reserved_words.get(t.value, 'IDENTIFIER')
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return t
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def t_NUMBER(self, t):
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r'\d+'
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t.value = int(t.value)
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return t
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def t_newline(self, t):
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r'\n+'
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t.lexer.lineno += len(t.value)
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self.latest_newline = t.lexpos
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t_ignore = ' \t'
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def t_error(self, t):
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raise TimexLexerError('Error on line %s, col %s: Unexpected character:'
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' %s ' % (t.lexer.lineno,
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t.lexpos - self.latest_newline,
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t.value[0]))
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if __name__ == '__main__':
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logging.basicConfig()
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lexer = TimexLexer(debug=True)
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lexer.input(sys.stdin.read())
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token = lexer.token()
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while token:
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print('%-20s%s' % (token.value, token.type))
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token = lexer.token()
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