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.
8 lines
209 B
Text
8 lines
209 B
Text
def sum (as : Array Nat) : Nat :=
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let rec go (i : Nat) (s : Nat) : Nat :=
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if h : i < as.size then
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go (i+2) (s + as.get ⟨i, h⟩) -- Error
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else
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s
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termination_by as.size - i
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go 0 0
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