lean4-htt/src/Lean/Elab/Mixfix.lean
2021-06-28 13:52:04 -07:00

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/-
Copyright (c) 2020 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
import Lean.Elab.Attributes
namespace Lean.Elab.Command
@[builtinMacro Lean.Parser.Command.mixfix] def expandMixfix : Macro := fun stx =>
withAttrKindGlobal stx fun stx => do
match stx with
| `(infixl $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? $op => $f) =>
let prec1 := quote <| (← evalOptPrec prec) + 1
`(notation $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? lhs$[:$prec]? $op:strLit rhs:$prec1 => $f lhs rhs)
| `(infix $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? $op => $f) =>
let prec1 := quote <| (← evalOptPrec prec) + 1
`(notation $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? lhs:$prec1 $op:strLit rhs:$prec1 => $f lhs rhs)
| `(infixr $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? $op => $f) =>
let prec1 := quote <| (← evalOptPrec prec) + 1
`(notation $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? lhs:$prec1 $op:strLit rhs $[: $prec]? => $f lhs rhs)
| `(prefix $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? $op => $f) =>
`(notation $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? $op:strLit arg $[: $prec]? => $f arg)
| `(postfix $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? $op => $f) =>
`(notation $[: $prec]? $[(name := $name)]? $[(priority := $prio)]? arg$[:$prec]? $op:strLit => $f arg)
| _ => Macro.throwUnsupported
where
-- set "global" `attrKind`, apply `f`, and restore `attrKind` to result
withAttrKindGlobal stx f := do
let attrKind := stx[0]
let stx := stx.setArg 0 mkAttrKindGlobal
let stx ← f stx
return stx.setArg 0 attrKind
end Lean.Elab.Command