fa64c072ab
https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/Local.20functions.20in.20instances/near/285333999
15 lines
321 B
Text
15 lines
321 B
Text
inductive Foo where
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| mk : Nat → Foo
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| boo : String → Foo
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instance : ToString Foo where
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toString o := match o with
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| .mk n => aux1 n
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| .boo s => aux2 s
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where
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aux1 (n : Nat) : String :=
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s!".mk {n}"
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aux2 (s : String) : String :=
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s!".boo {s}"
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example : toString (Foo.mk 10) = ".mk 10" := rfl
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