On Wed, Aug 27, 2008 at 02:23:04AM +0100, Lennart Augustsson wrote:
BTW, I'm not contradicting that the use of global variables can be necessary when interfacing with legacy code, I just don't think it's the right design when doing something new.
As with all design decisions, it is sometimes the right thing and sometimes the wrong one. And sometimes the most expedient. (which, occasionally, is a perfectly valid driving force behind a certain bit of coding). However, I am fully convinced it is necessary. You don't even have to look further than Haskell 98 to find a use in the Random module, and Data.Unique _depends_ on the state being global for correctness. now, _interfaces_ that depend on global state are a completely different matter. To quote what I wrote in the jhc manual: "Note, top level global variables can be indicative of design issues. In general, they should only be used when necessary to interface with an external library, opaque uses inside a library where the shared state can not be externally observed, or inside your Main program as design dictates." However, note the weasel words. Those are in there on purpose, every design calls for different solutions. To blanketly say certain constructs are just wrong to the point of disallowing them in the language, especially when they are common practice at the moment, just doesn't seem right. John -- John Meacham - ⑆repetae.net⑆john⑈