I agree. In the official documentation:"*Even though* Float64 <: Real *we
DO NOT have* Point{Float64} <: Point{Real}".
On Monday, March 16, 2015 at 7:02:16 PM UTC+1, Ivar Nesje wrote:
>
> If you have a signature
>
> function commonprefix(str_arr::Array{AbstractString,1})
>
> It means that it should only work on Arrays with element type
> AbstractString. If you call it with Array{UTF8String,1}, you can't push! a
> reference to a ASCIIString onto the array (without conversion), so the
> method does not apply. This is an arbitrary choice that the designers of
> Julia made that most users has questioned the decision at some point. The
> technical terms are invariance and contravariance.
>
> Ivar
>
> mandag 16. mars 2015 15.24.13 UTC+1 skrev Sisyphuss følgende:
>>
>> I have just made the same mistake this morning.
>>
>>
>>
>> On Monday, March 16, 2015 at 1:05:32 PM UTC+1, Simon Danisch wrote:
>>>
>>> It should be commonprefix{S <: AbstractString}(str_arr::Vector{S})
>>> (Vector -> typealias Vector{T} Array{T, 1})
>>> What you told julia with Vector{AbstractString} is that the function
>>> only takes Vectors with the element type of AbstractString.
>>> Though, ["asdasd", "adasd"] has the concrete element type of ASCIIString
>>>
>>> Am Montag, 16. März 2015 12:50:19 UTC+1 schrieb Julia User:
>>>>
>>>> just some simple beginners question:
>>>>
>>>>
>>>> *1. Question:* Why does *Array{AbstractString,1}*: not work?
>>>>
>>>> ERROR: LoadError: MethodError: `commonprefix` has no method matching
>>>> commonprefix(::Array{ASCIIString,1})
>>>>
>>>>
>>>> function commonprefix(str_arr::Array{AbstractString,1})
>>>> min_idx = indmin(str_arr)
>>>> common_prefix = str_arr[min_idx]
>>>> common_length = length(common_prefix)
>>>> # Other code skipped
>>>> return common_length
>>>> end
>>>>
>>>> common_endidx = commonprefix(["/home/Downloads/test",
>>>> "/home/Downloads/othertest"])
>>>> println("AbstractString: $common_endidx")
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *2. Question:* is there an easy way to avoid rewriting most of the
>>>> functions code
>>>>
>>>>
>>>>
>>>> function commonprefix(str_arr::Array{ASCIIString,1})
>>>> min_idx = indmin(str_arr)
>>>> common_prefix = str_arr[min_idx]
>>>> common_length = length(common_prefix)
>>>> # Other code skipped
>>>> return common_length
>>>> end
>>>>
>>>> function commonprefix(str_arr::Array{UTF8String,1})
>>>> min_idx = indmin(str_arr)
>>>> common_prefix = str_arr[min_idx]
>>>> common_length = length(common_prefix)
>>>> # Other code skipped
>>>> return common_length
>>>> end
>>>>
>>>>
>>>> # ASCIIString
>>>> common_endidx = commonprefix(["/home/Downloads/test",
>>>> "/home/Downloads/othertest"])
>>>> println("ASCIIString: $common_endidx")
>>>> # UTF8String
>>>> common_endidx = commonprefix(["/home/Downloads/átomos",
>>>> "/home/Downloads/otherátomos"])
>>>> println("UTF8String: $common_endidx")
>>>>
>>>>
>>>>
>>>> Thanks
>>>>
>>>>
>>>>
