Here begins the lesson on Embrace, Extend and Extinguish (EEE). Classically, this technique is used to perpetuate vendor lock-in by introducing small incompatibilities into a standard interface, in order to prevent effective interoperability, or (shudder) even substitutability of competing products based on that interface. This EEE strategy has worked well so far for Microsoft, with the web browser, with Java, with Kerberos, etc. It is interesting to note that this technique can work equally well with Microsoft’s own standards, like OOXML.<\/p>\n
An easy way to find these extension points is to search the OOXML specification for “application-defined” or “implementation-defined”. You will find dozens of them, such as:<\/p>\n
So, one might ask, what exactly does “implementation-defined”mean? Here is how OOXML defines it and related terms:<\/p>\n
behavior, implementation-defined \u2014 Unspecified behavior where each implementation documents that behavior, thereby promoting predictability and reproducibility within any given implementation. (This term is sometimes called \u201capplication-specific behavior\u201d.)<\/p>\n
behavior, locale-specific \u2014 Behavior that depends on local conventions of nationality, culture, and language.<\/p>\n
behavior, unspecified \u2014Behavior where this Standard imposes no requirements. [Note: To add an extension, an implementer must use the extensibility mechanisms described by this Standard rather than trying to do so by giving meaning to otherwise unspecified behavior. end note]<\/p><\/blockquote>\n
Note that this is not an entirely novel definition. Anyone who has spent time reading over the C and C++ Programming Language standards, in ANSI or in ISO, will recall a similar set of definitions. For example, these from ISO\/IEC 9899:1999 C-Programming Language:<\/p>\n
implementation-defined behavior
unspecified behavior where each implementation documents how the choice is made<\/p>\nlocale-specific behavior
behavior that depends on local conventions of nationality, culture, and language that each implementation documents<\/p>\nunspecified behavior
behavior where this International Standard provides two or more possibilities and
imposes no further requirements on which is chosen in any instance<\/p><\/blockquote>\nSo, you can see that OOXML pretty much copies these definitions. However, ISO standards like ISO\/IEC 9899:1999 go one step further and make an additional statement in their conformance clause, something that is distinctly missing from OOXML:<\/p>\n
“An implementation shall be accompanied by a document that defines all implementation-defined and locale-specific characteristics and all extensions.”<\/p><\/blockquote>\n