diff --git a/src/main/kotlin/com/shr4pnel/ferretirc/net/MessageParser.kt b/src/main/kotlin/com/shr4pnel/ferretirc/net/MessageParser.kt
index cd46c00..6d05fb0 100644
--- a/src/main/kotlin/com/shr4pnel/ferretirc/net/MessageParser.kt
+++ b/src/main/kotlin/com/shr4pnel/ferretirc/net/MessageParser.kt
@@ -64,18 +64,31 @@ class MessageParser(val incoming: Channel<String>) {
             }
 
             class NumericCommand(override val command: String, override val parameters: List<String>) : Command(command, parameters) {
+                private enum class RPL(val underlying: Int) {
+                    ISUPPORT(5),
+                    LISTSTART(321),
+                    LIST(322),
+                    LISTEND(323),
+                    NONE(0xbeef), ;
+
+                    companion object {
+                        val rplMap = RPL.entries.associateBy { it.underlying }
+                        infix fun from(value: Int) = rplMap[value] ?: NONE
+                        infix fun from(value: String) = from(value.toInt())
+                    }
+                }
+
                 override fun toServerMessage() =
-                    when (command.toInt()) {
-                        5 -> ServerMessage.Numeric.RPL_ISUPPORT(getNonTrailingParameterString())
-                        321 -> ServerMessage.Numeric.RPL_LISTSTART()
-                        322 ->
-                            ServerMessage.Numeric.RPL_LIST(
-                                parameters[1],
-                                parameters[2].toInt(),
-                                getTrailingParameterString(),
-                            )
-                        323 -> ServerMessage.Numeric.RPL_LISTEND()
-                        else -> ServerMessage.UNIMPLEMENTED(parameters.toString())
+                    when (RPL from command) {
+                        RPL.ISUPPORT -> ServerMessage.Numeric.RPL_ISUPPORT(getNonTrailingParameterString())
+                        RPL.LISTSTART -> ServerMessage.Numeric.RPL_LISTSTART()
+                        RPL.LIST -> ServerMessage.Numeric.RPL_LIST(
+                            parameters[1],
+                            parameters[2].toInt(),
+                            getTrailingParameterString(),
+                        )
+                        RPL.LISTEND -> ServerMessage.Numeric.RPL_LISTEND()
+                        RPL.NONE -> ServerMessage.UNIMPLEMENTED(parameters.toString())
                     }
             }
         }