* @param fnNode The function node. Only used for error reporting.
* @return The result of the function called on the given arguments.
*/
protected SoyData computeFunction(String fnName, List<SoyData> args, FunctionNode fnNode) {
SoyJavaRuntimeFunction fn = soyJavaRuntimeFunctionsMap.get(fnName);
if (fn == null) {
throw new RenderException(
"Failed to find Soy function with name '" + fnName + "'" +
" (function call \"" + fnNode.toSourceString() + "\").");
}