[Laszlo-user] [Laszlo-dev] Need to be able to override resource declarations in OpenLaszlo without warnings.

[Elliot Winard]

We can't specify the long name in CSS right now.  I don't know enough 
about the implementation to know exactly why.

http://www.openlaszlo.org/jira/browse/LPP-3477

P T Withington wrote:
> Remind me why we have resources?  They just seem to serve to give you 
> a short name for a longer name.  Why can't we skip resources 
> altogether and specify the long name directly in CSS?  Is this due to 
> some underlying limitation in the SWF runtime?
>
> On 2007-08-29, at 12:56 EDT, Elliot Winard wrote:
>
>> I like this proposal.
>>
>> That means that there are now two ways to "skin" an app -
>> * using CSS
>> * overwriting named resources
>>
>> Using overwritten resources will make compile-time skinning more 
>> palatable than the 2-step CSS option we currently have.  It'd still 
>> be nice to be able to support assigning of resource file-names in 
>> CSS.  (LPP-3477 <http://www.openlaszlo.org/jira/browse/LPP-3477>)
>> -e
>>
>> Bret Simister wrote:
>>> I prefer putting the responsibility on the developer creating the 
>>> library, rather than on the developer using it.
>>>
>>> Hence,
>>>
>>> <!-- mylibrary.lzx -->
>>> <library>
>>>     <resource name="logo" src="logo.png" replaceable="true" />
>>> </library>
>>>
>>> would allow a developer using the library to write the following
>>>
>>> <canvas>
>>>     <inlcude href="mylibrary.lzx" />
>>>     <resource name="logo" src="logo2.png" />
>>> </canvas>
>>>
>>> and see no warnings upon compile. This seems the cleanest approach 
>>> to me.
>>> It lets the library developer be explicit about which resources were 
>>> designed
>>> to be replaced.
>>>
>>> I am also  OK with  Henry's suggestion about using a compiler flag 
>>> to show warnings
>>> when you need to check for resource conflicts. The nice thing about 
>>> that approach is that
>>> it has minimal impact upon the language.
>>>
>>> -Bret
>>>
>>>
>>>
>>> On Wed, Aug 29, 2007 at  8:03 AM, Elliot Winard wrote:
>>>
>>>> I can see something like that working -
>>>> <resource name="logo" src="blah.png" force="true" />
>>>>
>>>> If the force attribute is present, it overwrites other declarations 
>>>> of logo and does *not* emit a warning.
>>>> The force attribute could mean both "replaceable" and "suppress 
>>>> warning".
>>>> The warning could suggest that the force attribute be used if the 
>>>> user intends to overwrite in case of conflict.
>>>>
>>>>
>>>> Resources in libraries could define the force
>>>> <library>
>>>>   <resource name="logo" src="logo.png" force="true" />
>>>> </library>
>>>>
>>>> <library>
>>>>   <resource name="logo" src="logo2.png" force="true" />
>>>> </library>
>>>>
>>>> Hrm.  Come to think of it, that feels wrong. Would it be too much 
>>>> of a change if there are two new attributes for resource - force 
>>>> and replaceable?
>>>> @force would be tell the compiler not to emit a warning if this 
>>>> resource overwrites another.
>>>> @replaceable would tell the compiler not to emit a warning if this 
>>>> resource is overwritten
>>>>
>>>> If these two attributes aren't present the current behavior remains.
>>>> So resources in Webtop libraries would look like this -
>>>> <library>
>>>>   <resource name="logo" src="logo.png" replaceable="true" />
>>>> </library>
>>>>
>>>> -e
>>>>
>>>> Sarah Allen wrote:
>>>>> That is exactly the dilemma.  The tension is between a the 
>>>>> frustration of an accidental override and the frustration if you 
>>>>> want to set up your library to allow customizing a resource, where 
>>>>> you have to provide a resource file and library separately and 
>>>>> then the user of the library needs to create a new resource file 
>>>>> and include all your resources except the logo and include the logo.
>>>>>
>>>>> I suppose there could be some kind of flag that says that I meant 
>>>>> to override this resource, like:
>>>>> <resource name="logo" src="logo.png" replace="true"/>
>>>>>
>>>>> I don't know if that would complicate the implementation or the 
>>>>> language folk would consider it weird, but as a user of the 
>>>>> language it would work for me.
>>>>>
>>>>> Sarah
>>>>>
>>>>>
>>>>> On Wed, Aug 29, 2007 at  5:01 AM, Elliot Winard wrote:
>>>>>
>>>>>
>>>>> I don't know about removing the platform warnings.
>>>>>
>>>>> If I include two libraries that have resources with conflicting 
>>>>> names, I want to know about it.  For example - I might include 
>>>>> multiple libraries , each defining a 'logo' resource and expecting 
>>>>> the logo to be sized a certain way -
>>>>>    <include "mailwindow" />
>>>>>    <include "stockwindow" />
>>>>>
>>>>> I want the compiler to tell me that the stockwindow's logo is 
>>>>> overwriting the mailwindow's logo.  Warnings are informative, 
>>>>> non-fatal and should be used to provide this kind of information.
>>>>> This proposal skirts CSS altogether.  If this gets implemented as 
>>>>> proposed then the display of warnings should be configurable at 
>>>>> compile-time.  I think it would be confusing to users if resources 
>>>>> (or classes or instances) get clobbered without any warning.
>>>>> -e
>>>>>
>>>>> Sarah Allen wrote:
>>>>>>  I think this is an excellent proposal.  cc'ing laszlo-user to 
>>>>>> see if
>>>>>> other folks developing in LZX have strong feelings about this ...
>>>>>>
>>>>>>
>>>>>> On Tue, Aug 28, 2007 at  3:12 PM, Bret Simister wrote:
>>>>>>
>>>>>>
>>>>>> Currently, in the OpenLaszlo platform, it was decided that 
>>>>>> declaring a
>>>>>> resource twice within an LZX app
>>>>>> causes a server warning. This was intended to help developers 
>>>>>> just in
>>>>>> case they accidentally overrode a
>>>>>> resource that had already been  declared in another library.
>>>>>>
>>>>>>
>>>>>> <!-- the following code produces a warning, but still compiles -->
>>>>>> <canvas>
>>>>>>     <resource name="logo" src="logo.gif" />
>>>>>>     <resource name="logo" src="logo2.gif" />
>>>>>>
>>>>>>  <!-- view appears with logo2.gif -->
>>>>>>     <view resource="logo" />
>>>>>> </canvas>
>>>>>>
>>>>>>
>>>>>>
>>>>>> At this time, I would suggest that  the  platform remove these
>>>>>> warnings and have
>>>>>> the last resource declaration override all other previous 
>>>>>> declarations.
>>>>>>
>>>>>>
>>>>>> Here is why...
>>>>>>
>>>>>>
>>>>>> OpenLaszlo now has a CSS implementation. It gives developers an
>>>>>> elegant method
>>>>>> of skinning their applications. This works, currently,  by first
>>>>>> declaring a resource
>>>>>>
>>>>>>
>>>>>> <resource  name="someimage_rsc"  src="somepath/someimage.jpg" />
>>>>>>
>>>>>>
>>>>>> and then referring to that resource in a CSS selector
>>>>>>
>>>>>>
>>>>>> view[name="someview"] {
>>>>>> resource: someimage_rsc;
>>>>>> }
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> If a developer builds a library ....
>>>>>>
>>>>>>
>>>>>>   myCustomLibrary      ( folder )
>>>>>>      library.lzx
>>>>>>      myresources.lzx ( contains many resource definitions including
>>>>>> 'lowerRightCorner_rsc' )
>>>>>>      mystyles.css    ( contains many selectors including one that
>>>>>> references 'lowerRightCorner_rsc' )
>>>>>>      ...             ( other class and source image files )
>>>>>>
>>>>>>
>>>>>> where  library.lzx  includes both   myresources.lzx and mystyles.css
>>>>>>     Then library can be used with a simple inclusion in the main 
>>>>>> app.
>>>>>>
>>>>>>
>>>>>> <canvas>
>>>>>>
>>>>>>
>>>>>> <include name="myCustomLibrary" />
>>>>>>
>>>>>>
>>>>>> <!-- instance of a class from myCustomLibrary -->
>>>>>> <mycustomclass />
>>>>>>
>>>>>>
>>>>>> </canvas>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Let's assume that " mycustomclass " contains a number of resources,
>>>>>> and that you ( as a developer )
>>>>>> only want to change one of those resources . The simplest method to
>>>>>> accomplish this would be ...
>>>>>>
>>>>>>
>>>>>> <canvas>
>>>>>>
>>>>>>
>>>>>> <include name="myCustomLibrary" />
>>>>>>
>>>>>>
>>>>>> <!-- override resource definition "lowerRightCorner_rsc" defined
>>>>>> earlier in myresouces.lzx -->
>>>>>> <resource name="lowerRightCorner"
>>>>>> src="my_new_path/my_lower_right_corner.jpg" />
>>>>>>
>>>>>>
>>>>>>
>>>>>> <!-- instance of mycustomclass that will now display
>>>>>>          the new resource based on the unchanged css selector -->
>>>>>> <mycustomclass />
>>>>>>
>>>>>>
>>>>>> </canvas>
>>>>>>
>>>>>>
>>>>>> Currently, this code would cause a compiler warning. To avoid these
>>>>>> warnings ( without changing OpenLaszlo ) the  resouces.lzx 
>>>>>> file(s) and
>>>>>> possibly the  library .lzx would have to be edited.
>>>>>>
>>>>>>
>>>>>> If instead, we allow for resource overriding, then ...
>>>>>>
>>>>>>
>>>>>> 1) the original CSS and  resource files will remain unchanged
>>>>>> 2) The old resource for " lowerRightCorner"  would NOT be 
>>>>>> included in
>>>>>> the app
>>>>>> 3) There  would be clean separation between external libraries 
>>>>>> and the
>>>>>> skinning of theses libraries  included in an application.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>