Generate reasonable ReprKind method for kinded unions.

schema/gen/go/genUnionReprKinded.go

@@ -70,7 +70,26 @@ func (g unionReprKindedReprGenerator) EmitNodeTypeAssertions(w io.Writer) {
 }
 
 func (g unionReprKindedReprGenerator) EmitNodeMethodReprKind(w io.Writer) {
-	// FIXME wow
+	doTemplate(`
+		func (n *_{{ .Type | TypeSymbol }}__Repr) ReprKind() ipld.ReprKind {
+			{{- if (eq (.AdjCfg.UnionMemlayout .Type) "embedAll") }}
+			switch n.tag {
+			{{- range $i, $member := .Type.Members }}
+			case {{ add $i 1 }}:
+				return {{ $member.RepresentationBehavior | KindSymbol }}
+			{{- end}}
+			{{- else if (eq (.AdjCfg.UnionMemlayout .Type) "interface") }}
+			switch n2 := n.x.(type) {
+			{{- range $i, $member := .Type.Members }}
+			case {{ $member | TypeSymbol }}:
+				return {{ $member.RepresentationBehavior | KindSymbol }}
+			{{- end}}
+			{{- end}}
+			default:
+				panic("unreachable")
+			}
+		}
+	`, w, g.AdjCfg, g)
 }
 
 // A bunch of these methods could be improved by doing a gen-time switch for whether any of the possible members are the relevant kind at all;

schema/gen/go/templateUtil.go

@@ -54,6 +54,30 @@ func doTemplate(tmplstr string, w io.Writer, adjCfg *AdjunctCfg, data interface{
 					panic("invalid enumeration value!")
 				}
 			},
+			"KindSymbol": func(k ipld.ReprKind) string {
+				switch k {
+				case ipld.ReprKind_Map:
+					return "ipld.ReprKind_Map"
+				case ipld.ReprKind_List:
+					return "ipld.ReprKind_List"
+				case ipld.ReprKind_Null:
+					return "ipld.ReprKind_Null"
+				case ipld.ReprKind_Bool:
+					return "ipld.ReprKind_Bool"
+				case ipld.ReprKind_Int:
+					return "ipld.ReprKind_Int"
+				case ipld.ReprKind_Float:
+					return "ipld.ReprKind_Float"
+				case ipld.ReprKind_String:
+					return "ipld.ReprKind_String"
+				case ipld.ReprKind_Bytes:
+					return "ipld.ReprKind_Bytes"
+				case ipld.ReprKind_Link:
+					return "ipld.ReprKind_Link"
+				default:
+					panic("invalid enumeration value!")
+				}
+			},
 			"add":   func(a, b int) int { return a + b },
 			"title": func(s string) string { return strings.Title(s) },
 		}).