"...I came up with three primary classifications for thinking about
the UML: UmlAsSketch \<http://martinfowler.com/bliki/UmlAsSketch.html> ,
UmlAsBlueprint \<http://martinfowler.com/bliki/UmlAsBlueprint.html> , and
UmlAsProgrammingLanguage
\<http://martinfowler.com/bliki/UmlAsProgrammingLanguage.html> ....one of the problems that I, and some others, are having with UML 2 is because there are many changes that have been introduced to increase its precision - changes that are primarily to make it more
suitable for UmlAsBlueprint and UmlAsProgrammingLanguage. But
these changes increase the bulk of the UML - and thus make it harder for
those of who prefer UmlAsSketch...." via [Martin Fowler's Bliki
\<http://martinfowler.com/bliki/UmlMode.html> ]
Martin's right, but he's being too polite. The only people who want UML to become a programming language are in the trade. In the real world, the only way that UML is accepted is as a sketch. Martin probably knows this better than anyone, as his book UML Distilled (http://www.amazon.com/exec/obidos/ASIN/0321193687/thinkinginnet-20) has deservedly sold roughly a bazillion more copies than the UML Reference Manual (http://www.amazon.com/exec/obidos/ASIN/020130998X/thinkinginnet-20)