36 lines
1.2 KiB
Text
36 lines
1.2 KiB
Text
#lang lean4
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/-
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Copyright (c) 2020 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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namespace Lean
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structure InternalExceptionId :=
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(idx : Nat := 0)
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instance : Inhabited InternalExceptionId := ⟨{}⟩
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instance : HasBeq InternalExceptionId :=
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⟨fun id₁ id₂ => id₁.idx == id₂.idx⟩
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builtin_initialize internalExceptionsRef : IO.Ref (Array Name) ← IO.mkRef #[]
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def registerInternalExceptionId (name : Name) : IO InternalExceptionId := do
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let exs ← internalExceptionsRef.get
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if exs.contains name then throw $ IO.userError s!"invalid internal exception id, '{name}' has already been used"
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let nextIdx := exs.size
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internalExceptionsRef.modify fun a => a.push name
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pure { idx := nextIdx }
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def InternalExceptionId.toString (id : InternalExceptionId) : String :=
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s!"internal exception #{id.idx}"
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def InternalExceptionId.getName (id : InternalExceptionId) : IO Name := do
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let exs ← internalExceptionsRef.get
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let i := id.idx;
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if h : i < exs.size then
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pure $ exs.get ⟨i, h⟩
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else
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throw $ IO.userError "invalid internal exception id"
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end Lean
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