On Friday 19 Nov 2004 2:27 pm, Benjamin Franksen wrote: > Implicit parameters are evil, agreed. Their deficiencies should be added > as a warning to the docs (with many exclamation marks).
Well I dunno. Maybe whatever's currently wrong with them can be fixed up. But I can't say they're something I've ever felt a need for. But it's ironic that some folk advocate the use of this (mis?)feature as a solution to the (so-called) "global variables" problem. I don't like this idea at all, but at least they recognise that there is a problem. > But toplevel > things with identity (TWI) are evil as well, *especially* if they are > easy to use. Just repeating this again and again doesn't make it any more true. Neither you or any of the other nay-sayers have provided any evidence or credible justification for this assertion, nor have any of you provided any workable alternative for even the simplest example. Lennart has yet to explain how he proposes to implement his supposedly safer "openDevice". You have yet to explain how you propose to deal with stdout etc.. BTW, top level TWI's are easy to create anyway, via the *unsound* unsafePerformIO hack. The evil here not their existance, it is the unsoundness of their creation mechanism. Given that in the absence of anything better folk are going to continue to use this (because it really is necessary sometimes), objecting to the provision of a sound alternative is just silly. This is the "militant denial" I was talking about. And of course there's one top level TWI that none of us can live without. I am refering to the unique and stateful "world" that is implicitly referenced by all IO operations (with the possible exception of those operations I would like to put in the "SafeIO" monad). So is this evil too? Perhaps it is, but if so, I'd like to know how you propose to live without it and what purpose the IO monad would serve in such a situation. Regards -- Adrian Hey _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
