On 08/26/2011 02:38 PM, Adam Ruppe wrote:
My pet feature request could do this too. User defined attributes combined with a list of functions called by a function.=== @custom("mysafe") void foo() {} void bar() {} @custom("mysafe") void main() { foo(); bar(); } CheckCustomSafety!("mysafe", main); template CheckCustomSafety(string attribute, alias func) { static if(!__traits(hasCustomAttribute(func, attribute)) pragma(error, func.stringof ~ " is not " ~ attribute); foreach(f; __traits(getCalledFunctions, func)) CheckCustomSafety!(attribute, f); } ==== And throw in an or for trusted. The reason I want this is to check for things more like custom purity, but I think it'd work for your custom safety too. (and user defined attributes are just useful for other things too!) The biggest problem I see with using my idea is the error message will probably suck.
I think it could be possible to provide decent error messages, by providing some means (via traits) to get line and file numbers of the calls. The biggest problem I see with this design is, that only functions reachable from main will be checked. I'd rather see something in the lines of
mysafe.d __traits(declareCustomAttribute, "mysafe"); // can detect name clash __traits(declareCustomAttribute, "mytrusted"); __traits(declareCustomAttribute, "mysystem");__traits(attribSetMutuallyExclusiveWithDefault, ["mysafe", "mytrusted","mysystem"],"mysystem");
__traits(registerStaticChecker, "mysafe", CheckMysafe); (the traits could be replaced by better syntax, of course)and then we could use int main() @mysafe {} which would automatically be checked.
There should also be some way to parameterize custom attributes, and to perform code transformations (probably that would require AST-macros and AST-pattern matching to be nice)
__traits(declareCustomAttribute, "memoized(int=int.max)"); // maximum size of hash table.
int foo(int x)@memoized(100){ ... } // memoize at most 100 values
