Interesting. So this only works with MXML or with ActionScript too?
I’m wondering if we can use this for typed arrays in externs compiled using compc. I ran into that problem recently. > On Mar 2, 2017, at 5:14 PM, Clint M <cmod...@gmail.com> wrote: > > It's in the docs: > http://help.adobe.com/en_US/flex/using/WS2db454920e96a9e51e63e3d11c0bf680e1-7ffe.html#WS2db454920e96a9e51e63e3d11c0bf69084-7a2c > > ArrayElementType metadata tag > > When you define an Array variable in ActionScript, you specify Array as the > data type of the variable. However, you cannot specify the data type of the > elements of the Array. > > To allow the Flex MXML compiler to perform type checking on Array elements, > you can use the [ArrayElementType] metadata tag to specify the allowed data > type of the Array elements, as the following example shows: > > public class MyTypedArrayComponent extends VBox { > > [ArrayElementType("String")] > public var newStringProperty:Array; > > [ArrayElementType("Number")] > public var newNumberProperty:Array; > ... > } > Note: The MXML compiler checks for proper usage of the Array only in MXML > code; it does not check Array usage in ActionScript code. > In this example, you specify String as the allowed data type of the Array > elements. If a user attempts to assign elements of a data type other than > String to the Array in an MXML file, the compiler issues a syntax error, as > the following example shows: > > <MyComp:MyTypedArrayComponent> > <MyComp:newStringProperty> > <fx:Number>94062</fx:Number> > <fx:Number>14850</fx:Number> > <fx:Number>53402</fx:Number> > </MyComp:newStringProperty> > </MyComp:MyTypedArrayComponent> > In this example, you try to use Number objects to initialize the Array, so > the compiler issues an error. > > You can also specify Array properties as tag attributes, rather than using > child tags, as the following example shows: > > <MyComp:MyTypedArrayComponent newNumberProperty="[abc,def]"/> > This MXML code generates an error because Flex cannot convert the Strings > "abc" and "def" to a Number. > > You insert the [ArrayElementType] metadata tag before the variable > definition. The tag has the following syntax: > > [ArrayElementType("elementType")] > The following table describes the property of the [ArrayElementType] > metadata tag: > > Property > > Type > > Description > > elementType > String > > Specifies the data type of the Array elements, and can be one of the > ActionScript data types, such as String, Number, class, or interface. > > You must specify the type as a fully qualified class name, including the > package. > > On Thu, Mar 2, 2017 at 6:10 AM, Harbs <harbs.li...@gmail.com> wrote: > >> I just noticed a few places in TLF where we have such metadata. For >> example: >> >> [ ArrayElementType("text.elements.TextFlowLine") ] >> private var _lines:Array; >> >> Does anyone know what that does? >>
