b5122b6a7b
This change * moves `termination_by` and `decreasing_by` next to the function they apply to * simplify the syntax of `termination_by` * apply the `decreasing_by` goal to all goals at once, for better interactive use. See the section in `RELEASES.md` for more details and migration advise. This is a hard breaking change, requiring developers to touch every `termination_by` in their code base. We decided to still do it as a hard-breaking change, because supporting both old and new syntax at the same time would be non-trivial, and not save that much. Moreover, this requires changes to some metaprograms that developers might have written, and supporting both syntaxes at the same time would make _their_ migration harder.
25 lines
512 B
Text
25 lines
512 B
Text
import Lean.Data.Parsec
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open Lean Parsec
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@[macro_inline] -- Error
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def f : Nat → Nat
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| 0 => 0
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| n + 1 => f n
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@[macro_inline] -- Error
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def g : Nat → Nat
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| 0 => 0
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| n + 1 => g n
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termination_by x => x
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@[macro_inline] -- Error
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def h : Nat → Nat → Nat
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| 0, _ => 0
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| n + 1, m => h n m
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termination_by x y => x
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@[macro_inline] -- Error
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partial def skipMany (p : Parsec α) (it : String.Iterator) : Parsec PUnit := do
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match p it with
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| .success it _ => skipMany p it
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| .error _ _ => pure ()
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