On Fri, 2005-10-07 at 17:43 -0600, Luke Palmer wrote: > No, you can't overload assignment at runtime because you can't > overload assigment at any time, so says the language spec (well, not > any formal spec; so says Larry as far as I remember).
I'm wearing my "just a programmer, not a denizen of p6l" hat. Pretend I don't know the difference between overloading assignment and setting special STORE magic and I want the option to be able to have Array do something meaningful and significant to both of us when I assign a constant scalar to it. Again, I don't care *how* I accomplish it, as long as I don't have to root around in the source code of Perl 6 itself to make it work. > As for the first argument, presumably people put type annotations on > their code so that we can do some reasoning and tell them about > errors. I don't want to use a module off of 6PAN that breaks my code because its type annotations have leaked out into the rest of my code and I have no idea what the compiler error messages mean. It's sort of the anti-$&, except it can make my program run faster. (Correct answers: depends on the question. Wrong answers: instantaneous.) It's up to the person who *runs* the code, not the person who writes a component and can't possibly decide from now 'til forever exactly every circumstance in which he will allow people to use the component, to decide what level of compiler complexity and strictness to allow. If my program takes a second to run, I don't want to spend several seconds performing type checks more suited for a long-running program. If my program's a network-bound server process that ought to share most of its memory, maybe I don't want to JIT things. If I'm running the final customer tests before delivering frozen bytecode to customers who won't be changing the code, maybe I want as many checks and optimizations as possible. Making the author of a module decide that is wrong. Maybe allowing a module author to request stricter typing within the module is fine, but it oughtn't be the last word on the subject. I've programmed in languages that froze certain library code at a specific level of strictness for philosophical and speed-related reasons. It was painful when I needed to do something that the language designers and library developers never thought I might need to do. Sure, I have a "just a programmer" hat, but that doesn't mean I can't use well-encapsulated magic when I really need it. To make this concrete -- Java's final: broken, wrong, stupid. Pick three. Types are abstractions and all abstractions break sometimes. Of the possible analysis features the compiler can perform by default, I prefer to enforce sensible symbol names, as-small-as-possible scopes, and lack of near and exact duplication. These to me are much more useful than an optional-until-someone-somewhere-uses-it type system that prevents me from finding the escape hatches purposely built into the language. -- c
