You can also define your own constructor that works the same as the issue
Tobias pointed to:
immutable Point
x::Float64
y::Float64
z::Float64
color::Int
collision::Bool
end
Point(pt::Point; x = pt.x, y = pt.y, z = pt.z, color = pt.color, collision
= pt.collision) = Point(x, y, z, color, collision)
setX(pt::Point, x::Float64) = Point(pt, x = x)
On Mon, Dec 8, 2014 at 4:16 PM, Tobias Knopp <tobias.kn...@googlemail.com>
wrote:
> please have a look at https://github.com/JuliaLang/julia/pull/6122 which
> looks like the way to go (once merged)
>
> Cheers
>
> Tobi
>
> Am Montag, 8. Dezember 2014 20:18:18 UTC+1 schrieb Josh Langsfeld:
>
>> On Monday, December 8, 2014 12:15:23 PM UTC-5, Utkarsh Upadhyay wrote:
>>>
>>> I have just tried playing with Julia and I find myself often copying
>>> `immutable` objects while changing just one field:
>>>
>>> function setX(pt::Point, x::Float64)
>>> # Only changing the `x` field
>>> return Point(x, pt.y, pt.z, pt.color, pt.collision, pt.foo, pt.bar);
>>> end
>>>
>>> Is there is any syntactical sugar to avoid having to write out all the
>>> other fields which are not changing (e.g. pt.y, pt.z, etc.) while creating
>>> a new object?
>>> Apart from making the function much easier to understand, this will also
>>> make it much less of a hassle to change fields on the type.
>>>
>>> Thanks.
>>>
>>
>> I played with it some more and this seems to work:
>>
>> defn = setdiff(names(Point), [:x])
>> @eval Point(x, $([:(pt.$n) for n in defn]...))
>>
>> Of course, this will only work for the x parameter which comes first in
>> the field list. I'm not sure how you might extend it to arguments in the
>> middle of the list, but maybe you can figure it out.
>>
>
