Oops, sorry, in my last posting there was obviously an error in my code
because I used the wrong syntax to call an array constructor. Here is
another example where now I am using the correct constructor syntax (I
think?). But I still get the same error message concerning 'apply'.
module testnestparam2
immutable Token{S,T}
m::S
t::T
end
typealias TDict{K,D} Token{Dict{K,D}, Int}
function makeADict()
a = TDict([1=>"a",2=>"c"], 5)
end
end
On Tuesday, October 7, 2014 12:29:49 PM UTC-4, [email protected] wrote:
>
> Here is a very short Julia code that gives a mysterious error message in
> the latest build (952). Is it an error in my code or a bug in Julia? (In
> addition to the answer to this question, I would also like help with the
> code design question in my previous posting of two hours ago.)
>
> Thanks,
> Steve
>
> module testnestparam2
>
> typealias ADict{K,D} Array{Dict{K,D},1}
>
> function makeADict()
> a = ADict([[-9=>"a"],[15=>"b"]]) #line 6
> println("a[1][-9] = ", a[1][-9])
> end
>
> end
>
> julia> testnestparam2.makeADict()
> ERROR: type: makeADict: in apply, expected Function, got
> Type{Array{Dict{K,D},1
> }
> in makeADict at
> c:\Users\vavasis\Documents\Projects\qmg21\julia\testnestparam2
> jl:6
>
>
>
> On Tuesday, October 7, 2014 10:05:09 AM UTC-4, [email protected] wrote:
>>
>> Thanks for the explanation! Although I think I understand your answer,
>> I'm not sure how to define the types to accomplish my goal.
>>
>> * a Token should have two parts, a container and a semitoken, both
>> abstract
>>
>> * an SDToken should be a specialization of Token in which the container
>> portion is SortedDict{K,D} for a specific K,D and the semitoken portion is
>> IntSemiToken (both parts concrete)
>>
>> * Some functions take SDToken's as input. These should be generic, i.e.,
>> work for all choices of K,D.
>>
>> * There are also generic functions that return SDTokens as output (in
>> which K and D are determined from the input args).
>>
>> Can I write typealias SDToken{K,D} Token{SortedDict{K,D},IntSemiToken}?
>> I tried this and got an unexpected error message:
>>
>> ERROR: type: test1: in apply, expected Function, got
>> Type{Token{SortedDict{K,D},
>> IntSemiToken}}
>> in test1 at
>> c:\Users\vavasis\Documents\Projects\qmg21\julia\testnestparam.jl:32
>>
>> (No 'apply' in my code!) And in any case, even if I could write this,
>> I'm not sure it solves the problem.
>>
>> -- Steve
>>
>>
>>
>> On Tuesday, October 7, 2014 2:15:01 AM UTC-4, Jutho wrote:
>>>
>>> I don't see the problem regarding point one.
>>>
>>> A type with parameters, as your SortedDict{D,K}, becomes an abstract
>>> type when the parameters are unspecified, e.g. SortedDict, but this is
>>> indeed printed/formatted with unspecified parameters put back (I guess with
>>> the name as you defined them), e.g. as SortedDict{D,K}.
>>>
>>> Regarding point 2, this relates to the invariance of parametric types.
>>>
>>> isa(t2,Token{SortedDict, IntSemiToken})
>>> will return false, because
>>> Token{SortedDict{Int64,ASCIIString},IntSemiToken} <: Token{SortedDict,
>>> IntSemiToken}
>>> is false. There are many discussions regarding this both on the forum
>>> and I guess in the manual. Search for invariance versus covariance of
>>> parametric types.
>>>
>>>
>>> Op dinsdag 7 oktober 2014 04:42:12 UTC+2 schreef [email protected]:
>>>>
>>>> The code below is an excerpt from a more complicated code I am writing.
>>>> It contains a parametrized type in which the parameter is itself another
>>>> parametrized type. I have attached the printout (0.4.0-dev+323). Notice
>>>> the error message at the end. My questions are:
>>>>
>>>> (1) How is it possible that the type of t includes dummy parameters K
>>>> and D, which aren't real types at all?
>>>>
>>>> (2) Why is Julia not able to match t2 but it is able to match t to the
>>>> signature of test0()?
>>>>
>>>> Thanks,
>>>> Steve Vavasis
>>>>
>>>>
>>>> julia> testnestparam.test1()
>>>> typeof(t) = Token{SortedDict{K,D},IntSemiToken}
>>>> typeof(t2) = Token{SortedDict{Int64,ASCIIString},IntSemiToken}
>>>> methods(test0) = # 1 method for generic function "test0":
>>>> test0(i::Token{SortedDict{K,D},IntSemiToken}) at
>>>> c:\Users\vavasis\Documents\Projects\qmg21\julia\testnestparam.jl:28
>>>> ERROR: `test0` has no method matching
>>>> test0(::Token{SortedDict{Int64,ASCIIString},IntSemiToken})
>>>> in test1 at
>>>> c:\Users\vavasis\Documents\Projects\qmg21\julia\testnestparam.jl:38
>>>>
>>>>
>>>> module testnestparam
>>>>
>>>> immutable IntSemiToken
>>>> address::Int
>>>> end
>>>>
>>>> immutable Token{T, S}
>>>> container::T
>>>> semitoken::S
>>>> end
>>>>
>>>> # take a token apart
>>>> semi(i::Token) = i.semitoken
>>>> container(i::Token) = i.container
>>>>
>>>> # put a token back together
>>>> assemble(m, s) = Token(m,s)
>>>>
>>>> type SortedDict{K, D} <: Associative{K,D}
>>>> bt::Dict{K,D}
>>>> end
>>>>
>>>> typealias SDToken Token{SortedDict, IntSemiToken}
>>>>
>>>> sdtoken_construct(m::SortedDict,int1::Int) =
>>>> SDToken(m, IntSemiToken(int1))
>>>>
>>>> test0(i::SDToken) = nothing
>>>>
>>>> function test1()
>>>> s = SortedDict([1=>"a",2=>"b"])
>>>> t = sdtoken_construct(s, 0)
>>>> t2 = assemble(t.container, t.semitoken)
>>>> println("typeof(t) = ", typeof(t))
>>>> println("typeof(t2) = ", typeof(t2))
>>>> println("methods(test0) = ", methods(test0))
>>>> test0(t)
>>>> test0(t2) #Line 38
>>>> end
>>>>
>>>> end
>>>>
>>>>
