Aka function arguments – I've been doing too much wrapping of C libraries
lately. Example:
function bar(f,y)
a = length(y)
[f(a) f(y)]
end
Which can be used like this:
bar(y) do x
# body of f(x)
end
You can also pass an explicit function argument as bar(f,y). (I swear this
email wasn't just a setup to write "barfy".)
On Thu, Mar 27, 2014 at 9:34 AM, Stefan Karpinski <[email protected]>wrote:
> Callbacks?
>
>
> On Thu, Mar 27, 2014 at 8:04 AM, andreas <[email protected]> wrote:
>
>>
>> Dear list,
>>
>> I'd like to be able to "pass" a function to a module, lets say
>> foo(x::Real). foo(x::Real) is used in the module and more methods are
>> added (which make use of foo(x::Real)).
>>
>> My idea is that the user loads the module and can then define
>> foo(x::Real). If the user later redefines this function, the package
>> should use the new foo(x::Real) for everything.
>>
>>
>> The small example below should make clear what I want. It works only
>> partly (on latest Windows pre-release), and not at all if the module is a
>> package (which is a concern for me).
>>
>> ## -----------
>> module mymodule
>>
>> ## foo(x::Array) requires foo(x::Real)
>> function foo(x::Array)
>> [foo(i/2) for i in x]'
>> end
>>
>> ## bar() requires both, foo(x::Array) and foo(x::Real)
>> function bar(y)
>> a=length(y)
>> [foo(a) foo(y)]
>> end
>>
>> export bar
>>
>> end
>> ## -----------
>>
>> using mymodule
>>
>> ## write foo(x::Real) in module
>> mymodule.foo(x::Real) = x^2
>>
>> mymodule.foo(2)
>> ## -> 4 # as expected
>> bar([1:3])
>> ## -> [9, 0.25, 1, 2.25] # as expected
>>
>> ## now change foo(x::Real) in module
>> mymodule.foo(x::Real) = x
>>
>> mymodule.foo(2)
>> ## -> 4 # changed as expected
>> bar([1:3])
>> ## -> [9, 0.25, 1, 2.25] # bar() uses still the old foo(x::Real)!
>>
>> I have the feeling that this is a very bad design and would appreciate
>> every suggestions how I could get a similar functionality in a cleaner way.
>>
>> Thanks!
>> Andreas
>>
>>
>
