26 lines
908 B
Text
26 lines
908 B
Text
import Lean
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open Lean Lean.Meta Lean.Elab Lean.Elab.Term Lean.Elab.Command Lean.PrettyPrinter
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syntax (name := roundtrip) "#roundtrip " ident : command
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@[commandElab roundtrip] def elabRoundtrip : CommandElab
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| `(#roundtrip%$tk $name:ident) => withoutModifyingEnv do
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let [name] ← resolveGlobalConst name.getId | throwError "cannot resolve name"
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let some cInfo ← (← getEnv).find? name | throwError "no such decl: {name}"
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let ns := cInfo.name.getRoot
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let cmdStx ← liftTermElabM none do
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let typeStx ← delab ns [] cInfo.type {}
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let valueStx ← delab ns [] cInfo.value! {}
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`(noncomputable def $(mkIdent (ns ++ `foo)):declId : $typeStx:term := $valueStx:term)
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elabCommand cmdStx
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| _ => throwUnsupportedSyntax
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#roundtrip Nat.add
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#roundtrip Std.Range.forIn.loop
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def hasMonadInst {α : Type u} {m : Type u → Type v} [Monad m] (x : m α) : m α := x
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#roundtrip hasMonadInst
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