Pampy: Pattern Matching for Python

Re:Pampy: Pattern Matching for Python by richard_shelton on Monday December 17, 2018 @04:53AM (#18697939)

And here is an another pattern matching implementation for Python [1]. It was made for compilers construction task and may look similiar for those who has an experience with Prolog, Stratego or Refal.

And here is a toy term rewriting system [2].

[1] https://github.com/true-grue/raddsl

[2] https://github.com/true-grue/code-snippets/blob/master/ttrs....

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Re:Pampy: Pattern Matching for Python by tom_mellior on Monday December 17, 2018 @06:59AM (#18698420)

> And here is an another pattern matching implementation for Python [1].

Oh, I like the prettier syntax:

    calc_rules = alt(
      Int(id),
      rule(BinOp("+", Int(X), Int(Y)), to(lambda v: Int(v.X + v.Y))),
      rule(BinOp("-", Int(X), Int(Y)), to(lambda v: Int(v.X - v.Y))),
      rule(BinOp("*", Int(X), Int(Y)), to(lambda v: Int(v.X * v.Y))),
      rule(BinOp("/", Int(X), Int(Y)), to(lambda v: Int(v.X // v.Y)))
    )

(https://github.com/true-grue/raddsl/blob/master/examples/cal...)

This way of sharing variable names between the pattern and the associated action is pretty neat. It's much nicer than Pampy's use of '_' for all variables.

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