public static IAstNode FindItemDefinition(this AstRoot ast, int position, string itemName) {
var scope = ast.GetNodeOfTypeFromPosition<IScope>(position);
var func = scope.FindFunctionDefinitionByName(itemName, position);
if (func != null) {
return func;
} else {
var v = scope.FindVariableDefinitionByName(itemName, position);
if (v != null) {
return v;
}
}
return null;
}