public static String namePartOf(String name) {
        name = name.startsWith("^") ? name.substring(1) : name;
        return name.split(":")[0];
    }
A method signature input and output has the form name:index.
This returns the name part without the index.
model-integration/src/main/java/ai/vespa/rankingexpression/importer/operations/IntermediateOperation.java