lean4-htt/src/Lean/Compiler/ImplementedByAttr.lean
2020-05-26 15:04:35 -07:00

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/-
Copyright (c) 2019 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
prelude
import Lean.Attributes
namespace Lean
namespace Compiler
def mkImplementedByAttr : IO (ParametricAttribute Name) :=
registerParametricAttribute `implementedBy "name of the Lean (probably unsafe) function that implements opaque constant" $ fun env declName stx =>
match env.find? declName with
| none => Except.error "unknown declaration"
| some decl =>
match attrParamSyntaxToIdentifier stx with
| some fnName =>
match env.find? fnName with
| none => Except.error ("unknown function '" ++ toString fnName ++ "'")
| some fnDecl =>
if decl.type == fnDecl.type then Except.ok fnName
else Except.error ("invalid function '" ++ toString fnName ++ "' type mismatch")
| _ => Except.error "expected identifier"
@[init mkImplementedByAttr]
constant implementedByAttr : ParametricAttribute Name := arbitrary _
@[export lean_get_implemented_by]
def getImplementedBy (env : Environment) (n : Name) : Option Name :=
implementedByAttr.getParam env n
end Compiler
end Lean