I think a little English would go a long way in the example below. For example, you could write "could not find a type for + that matched the arguments and results. A type for + are real * -> real, but there are more specialized types that say more about the inputs and outputs. Here they are: ... long list with newlines ...."
Robby On Thu, Sep 23, 2010 at 12:48 PM, Vincent St-Amour <[email protected]> wrote: > At Thu, 23 Sep 2010 13:32:42 -0400, > Matthias Felleisen wrote: >> You do want to see more than the general >> case when you are trying to eliminate >> casts from your numeric programs. I am >> not sure showing just the general case >> suffices. > > In the case of comparisons, since, if we ignore filters, all the > domains (Fixnum PositiveFixnum, Integer Natural, etc.) can be > generalized to Real Real *. Since the return type is the same > (Boolean) in all cases, only showing the general case does not cause > any loss of information. > > In the case of + and others, since the return types of all the cases > are different (Integer Integer -> Integer, Float Float -> Float, > etc.), no case is more general (in a subtyping sense) than the others, > so they are not eliminated. > > However, we do restrict the domains shown for errors related to +, but > in another way: we only show the domains for which the return type is > consistent with the expected type (the return type has to be a subtype > of the expected type). That means that you see the domains that would > give you a value of the required type: these are cases where you don't > need casts. > > So right now, if you have the following code: > (+ 'a 'b) > with an expected type of Integer, the error only mentions the domains > for which the return type would be Integer, but it mentions all of > them, and it ignores the cases that would result in a Float, or a > Complex. > > Vincent > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users > _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
