| 1 | #!/usr/bin/env python2
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| 2 | from __future__ import print_function
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| 3 | """
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| 4 | houston-fp demo
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| 5 | """
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| 6 |
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| 7 | import sys
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| 8 |
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| 9 | from demo_asdl import Token, expr_t, word_part_t, value, value_t
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| 10 |
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| 11 | from typing import List, Optional, cast
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| 12 |
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| 13 |
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| 14 | def main(argv):
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| 15 | # type: (List[str]) -> None
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| 16 |
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| 17 | # Better example:
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| 18 | #
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| 19 | # 1. Lexer() returning Token
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| 20 | # 2. Mututally recursive parsers storing Token as first class variants:
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| 21 | # WordParser
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| 22 | # ArithParser
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| 23 | # BoolParser
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| 24 | # ExprParser
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| 25 | #
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| 26 | # 3. Evaluators using Token
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| 27 | #
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| 28 | # 4. Errors bubbled up to top-level, using Token
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| 29 | #
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| 30 | # ...
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| 31 | #
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| 32 | # TypeScript example: https://github.com/oilshell/yaks
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| 33 |
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| 34 | tok = Token(3, 4, 5, 'foo')
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| 35 | print(tok)
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| 36 |
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| 37 | val = None # type: Optional[value_t]
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| 38 | ival = value.Int(42)
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| 39 |
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| 40 | val = ival
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| 41 |
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| 42 | my_word_part = None # type: Optional[word_part_t]
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| 43 | my_expr = None # type: Optional[expr_t]
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| 44 |
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| 45 | my_word_part = tok
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| 46 | my_expr = tok
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| 47 |
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| 48 | # Errors
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| 49 | #my_word_part = val
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| 50 |
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| 51 | #val = tok
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| 52 |
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| 53 |
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| 54 | if __name__ == '__main__':
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| 55 | try:
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| 56 | main(sys.argv)
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| 57 | except RuntimeError as e:
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| 58 | print('FATAL: %s' % e, file=sys.stderr)
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| 59 | sys.exit(1)
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