[ESW Wiki] Update of "its0506ReqConstraints" by YvesSavourel

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The following page has been changed by YvesSavourel:
http://esw.w3.org/topic/its0506ReqConstraints


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  = Constraints =
  
+ === Summary ===
+ 
+ 
+ It should be possible to associate one or more constraints to a specific content.
+ 
+ 
+ === Challenge/Issue ===
+ 
+ Translatable data may come with various constraints in the way they can be modified. For example, the content of the following <string> element must accommodate the length restriction imposed by the small display panel where it is used:
+ 
+ {{{<!-- LED display has only 16 characters -->
+ <string id="123">Printing...</string>}}}
+ 
+ In this case a standard method should be used for indicating the dimensions of the container so that localization tools can automatically recognize them and, when possible, enforce the constraint during translation.
+ 
+ Examples of constraints are:
+ 
+  * container size (e.g. maximum length, etc.)
+  * text allowed in a limited set of characters (e.g. translatable paths or filenames)
+  
+ These constraints may need to be defined at the schema level or they may need to be defined for specific instances of an element.
+ 
+ '''[[CL''' A certain constraint (e.g. container size) may only hold for a certain tool wihtin the overall processing chain. Thus, the important thing about the constraint is to ensure that the constraint holds when data is passed to that particular tool. Accordingly, a specific tool "sets" the constraint. When data is passed between other tools of the processing chain, the constraint may not be relevant.''']]'''
+ 
+ '''[[YS''' I'm adding the paragraph below to cover Christian's comment, but I'm not sure if it's really useable: I would expect the constraint to be linked to the data itself rather than the context. Because the next logical step would be that one can have different constraints depending on the context, then how do you apply those possibly conflicting constraints to the same chunk of data? ''']]'''
+ 
+ In some cases, the constraint may be applicable only for a given context.
+ 
+ 
+ === Notes ===
+ 
+ XSD (XML Schema Part 2: Datatypes Second Edition) provides a mechanism to define "Constraining Facets" http://www.w3.org/TR/xmlschema-2/#rf-facets that may provide some solution for this requirement, at least at the schema level.
+ 
+ Sometimes the constraint may need to be expressed using units different from the unit used in the document. For example, the maximum length of a string may need to be expressed in byte or pixels, or display cells instead of characters. This may lead to the need for quite a few parameters with the constraint (e.g. the encoding to use, or the font and point-size information, etc.)
+ 

Received on Thursday, 9 June 2005 10:48:15 UTC