hl7: allow round trip ACK triggers

Author: kardianos

decodeGroup.go

@@ -7,7 +7,7 @@ import (
 )
 
 type messageStructure interface {
-	MessageStructureID() string
+	MessageStructureID() []string
 }
 
 func newWalker(list []any, registry Registry) (*walker, error) {
@@ -20,13 +20,24 @@ func newWalker(list []any, registry Registry) (*walker, error) {
 	if !ok {
 		return nil, fmt.Errorf("first message must implment MessageStructure, %T does not", root)
 	}
-	code := ms.MessageStructureID()
-	if len(code) == 0 {
-		return nil, fmt.Errorf("message structure code empty, malformed message: %#v", root)
+	codeList := ms.MessageStructureID()
+	if len(codeList) == 0 {
+		return nil, fmt.Errorf("message structure code missing, malformed message: %#v", root)
 	}
-	vex, ok := registry.Trigger(code)
-	if !ok {
-		return nil, fmt.Errorf("message structure code not found %q", code)
+	var vex any
+	var code string
+	for _, c := range codeList {
+		if len(c) == 0 {
+			return nil, fmt.Errorf("message structure code empty, malformed message: %#v", root)
+		}
+		vex, ok = registry.Trigger(c)
+		if ok {
+			code = c
+			break
+		}
+	}
+	if vex == nil {
+		return nil, fmt.Errorf("message structure code not found %q", codeList)
 	}
 	tp := reflect.TypeOf(vex)
 

h220/datatype.go

@@ -21,30 +21,30 @@ type {{.ID}} struct {
 		{{.ID}} {{.|typeprefix}}{{.DataType}} `hl7:"{{.|tag}}"` {{end}}
 }
 {{if eq .ID "MSG"}}
-	func (d MSG) MessageStructureID() string {
+	func (d MSG) MessageStructureID() []string {
 		if len(d.MessageStructure) > 0 {
-			return d.MessageStructure
+			return []string{d.MessageStructure}
 		}
 		{{- if hasField "MessageCode" .Fields}}
 			if len(d.TriggerEvent) == 0 {
-				return d.MessageCode
+				return []string{d.MessageCode}
 			}
-			return d.MessageCode + "_" + d.TriggerEvent;
+			return []string{d.MessageCode + "_" + d.TriggerEvent, d.MessageCode};
 		{{end -}}
 		{{- if hasField "MessageType" .Fields}}
 			if len(d.TriggerEvent) == 0 {
-				return d.MessageType
+				return []string{d.MessageType}
 			}
-			return d.MessageType + "_" + d.TriggerEvent;
+			return []string{d.MessageType + "_" + d.TriggerEvent, d.MessageType};
 		{{end -}}
 	}
 {{end}}
 {{if eq .ID "CM_MSG"}}
-	func (d CM_MSG) MessageStructureID() string {
+	func (d CM_MSG) MessageStructureID() []string {
 		if len(d.TriggerEvent) == 0 {
-			return d.MessageType
+			return []string{d.MessageType}
 		}
-		return d.MessageType + "_" + d.TriggerEvent
+		return []string{d.MessageType + "_" + d.TriggerEvent, d.MessageType}
 	}
 {{end}}
 

h220/segment.go

@@ -21,7 +21,7 @@ type {{.ID}} struct {
 	{{if $mt}}
 	// MessageStructureID returns the code for the message structure.
 	// Implements the interface for decoders.
-	func (s {{.ID}}) MessageStructureID () string {
+	func (s {{.ID}}) MessageStructureID () []string {
 		return s.{{$mt}}.MessageStructureID()
 	}
 	{{end}}

h231/datatype.go

@@ -0,0 +1,2 @@
+MSH|^~\&|EnsembleHL7|ISC|A|B|20240528161200||ACK^R01|1716934339853485567|P|2.5|||||||||
+MSA|AA|1716934339853485567||||