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Re: Type restriction of elements in Array

From: Cameron McCormack <cam@mcc.id.au>
Date: Tue, 06 Dec 2011 10:44:08 +1100
Message-ID: <4EDD5748.7020301@mcc.id.au>
To: kisubs.song@samsung.com
CC: public-script-coord@w3.org
On 11/10/11 5:17 PM, Kisub Song wrote:
> Even though the original ECMAScript does not support the type
> restriction of array, I can implement arrays that allow values of
> specific type as their elements. in case of platform array object.
>
> What I am wondering is that allowing only specific type value for an
> array is right policy or not.
>
> If it is right policy, what should happen if user try to assign wrong
> type value to an array?
...
> var as = getTypeAArray(); // returns array of TypeA.
>
> var b = getTypeB(); // returns value of TypeB.
>
> as[0] = b; // What should happen in this situation?
> // exception? or silently ignoring?

The spec defines that to throw an exception, through step 2.3.5 of the 
platform array object [[DefineOwnProperty]] algorithm, which "converts" 
the JS value on the rhs of the assignment to the IDL type of the array's 
elements.

http://dev.w3.org/2006/webapi/WebIDL/#platform-array-object-defineownproperty
Received on Monday, 5 December 2011 23:44:44 UTC

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