lean4-htt/src/Lean/Elab/MacroRules.lean
2021-11-24 11:54:13 +01:00

54 lines
2.5 KiB
Text

/-
Copyright (c) 2021 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
import Lean.Elab.Syntax
import Lean.Elab.AuxDef
namespace Lean.Elab.Command
open Lean.Syntax
open Lean.Parser.Term hiding macroArg
open Lean.Parser.Command
/-
Remark: `k` is the user provided kind with the current namespace included.
Recall that syntax node kinds contain the current namespace.
-/
def elabMacroRulesAux (doc? : Option Syntax) (attrKind tk : Syntax) (k : SyntaxNodeKind) (alts : Array Syntax) : CommandElabM Syntax := do
let alts ← alts.mapM fun alt => match alt with
| `(matchAltExpr| | $pats,* => $rhs) => do
let pat := pats.elemsAndSeps[0]
if !pat.isQuot then
throwUnsupportedSyntax
let quoted := getQuotContent pat
let k' := quoted.getKind
if checkRuleKind k' k then
pure alt
else if k' == choiceKind then
match quoted.getArgs.find? fun quotAlt => checkRuleKind quotAlt.getKind k with
| none => throwErrorAt alt "invalid macro_rules alternative, expected syntax node kind '{k}'"
| some quoted =>
let pat := pat.setArg 1 quoted
let pats := pats.elemsAndSeps.set! 0 pat
`(matchAltExpr| | $pats,* => $rhs)
else
throwErrorAt alt "invalid macro_rules alternative, unexpected syntax node kind '{k'}'"
| _ => throwUnsupportedSyntax
`($[$doc?:docComment]? @[$attrKind:attrKind macro $(Lean.mkIdent k)]
aux_def macroRules $(mkIdentFrom tk k) : Macro :=
fun $alts:matchAlt* | _ => throw Lean.Macro.Exception.unsupportedSyntax)
@[builtinCommandElab «macro_rules»] def elabMacroRules : CommandElab :=
adaptExpander fun stx => match stx with
| `($[$doc?:docComment]? $attrKind:attrKind macro_rules%$tk $alts:matchAlt*) =>
expandNoKindMacroRulesAux alts "macro_rules" fun kind? alts =>
`($[$doc?:docComment]? $attrKind:attrKind macro_rules%$tk $[(kind := $(mkIdent <$> kind?))]? $alts:matchAlt*)
| `($[$doc?:docComment]? $attrKind:attrKind macro_rules%$tk (kind := $kind) | $x:ident => $rhs) =>
`($[$doc?:docComment]? @[$attrKind:attrKind macro $kind]
aux_def $(mkIdentFrom tk kind.getId) $kind : Macro := fun $x:ident => $rhs)
| `($[$doc?:docComment]? $attrKind:attrKind macro_rules%$tk (kind := $kind) $alts:matchAlt*) =>
do elabMacroRulesAux doc? attrKind tk (← resolveSyntaxKind kind.getId) alts
| _ => throwUnsupportedSyntax
end Lean.Elab.Command