package expressions import ( "reflect" "strings" ) func makeContainsExpr(e1, e2 func(Context) interface{}) func(Context) interface{} { return func(ctx Context) interface{} { a, aok := e1(ctx).(string) b, bok := e2(ctx).(string) return aok && bok && strings.Contains(a, b) } } func makeFilter(fn valueFn, name string, args []valueFn) valueFn { return func(ctx Context) interface{} { return ctx.Filters().runFilter(ctx, fn, name, args) } } func makeIndexExpr(obj, index func(Context) interface{}) func(Context) interface{} { return func(ctx Context) interface{} { ref := reflect.ValueOf(obj(ctx)) i := reflect.ValueOf(index(ctx)) switch ref.Kind() { case reflect.Array, reflect.Slice: switch i.Kind() { case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: n := int(i.Int()) if n < 0 { n = ref.Len() + n } if 0 <= n && n < ref.Len() { return ref.Index(n).Interface() } } case reflect.Map: if i.Type().ConvertibleTo(ref.Type().Key()) { item := ref.MapIndex(i.Convert(ref.Type().Key())) if item.IsValid() { return item.Interface() } } } return nil } } func makeObjectPropertyExpr(obj func(Context) interface{}, attr string) func(Context) interface{} { return func(ctx Context) interface{} { ref := reflect.ValueOf(obj(ctx)) switch ref.Kind() { case reflect.Array, reflect.Slice: if ref.Len() == 0 { return nil } switch attr { case "first": return ref.Index(0).Interface() case "last": return ref.Index(ref.Len() - 1).Interface() case "size": return ref.Len() } case reflect.String: if attr == "size" { return ref.Len() } case reflect.Map: value := ref.MapIndex(reflect.ValueOf(attr)) if value.Kind() != reflect.Invalid { return value.Interface() } } return nil } }