NCL, the standard declarative language of the Brazilian Terrestrial Digital TV System and ITU-T Recommendation for IPTV Services, provides a high level of reuse in the design of hypermedia applications. In this paper we detail how its design and conceptual model have succeeded in supporting reuse at a declarative level. NCL supports not only static but also running code reuse. It also allows for reuse inside applications, reuse between applications, and reuse of code spans stored in external libraries. For a specification language to promote reuse, however, it must have a number of usability merits. Aspects of NCL usability are thus analyzed with the Cognitive Dimensions of Notation framework.
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