44 lines
1.5 KiB
Text
44 lines
1.5 KiB
Text
/-
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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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prelude
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import Init.System.IO
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namespace Lean
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/-- Internal exception identifier -/
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structure InternalExceptionId where
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idx : Nat := 0
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deriving Inhabited, BEq
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/-- Internal exceptions registered in the system. -/
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builtin_initialize internalExceptionsRef : IO.Ref (Array Name) ← IO.mkRef #[]
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/--
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Register a new internal exception in the system.
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Each internal exception has a unique index.
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Throw an exception if the given name is not unique.
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This method is usually invoked using the `initialize` command.
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-/
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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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/-- Convert internal exception id into the message "internal exception #<idx>"-/
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def InternalExceptionId.toString (id : InternalExceptionId) : String :=
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s!"internal exception #{id.idx}"
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/-- Retrieve the name used to register the internal exception. -/
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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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return 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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