Nullable Int, Double, Float ?

[DiffrenzyKeymaster]

How do I do nullable types in MX2? Basically I’d like to have the equivalent of c#’s int?, float? etc.

Is there a way in MX2, without wrapping in a class, and ending up with a nullabletype.Value = xxx like syntax?

(I’m deserializing/serializing a generic type to xml, and need to only read/write values when they are present.)

PS: Speaking of nulls, I’d like to be able to do:

Monkey

If mystruct 'instead of If mystruct<>null

1 2	If mystruct 'instead of If mystruct<>null

like I can with types. Is that a builtin given for structs, or could it be added to MX2?

[Mark SiblyKeymaster]

There are no nullable types in mx2. There are variants though – see reflection in monkey2 language docs.

could it be added to MX2?

 

quite possibly – can you post an issue on github?

[DiffrenzyKeymaster]

Thanks Mark, I’ve put the Null issue on github (and also a request for the Elvis operator, which I really enjoy in C# )

Thanks for pointing me towards Variants. They a not a perfect for for my intended use, so I’ve ended up copying std.geom Vec2 and making a Vec1 struct, by removing the y vals and a few methods. If it’s not too weird, maybe MX2 could come with a Vec1 struct , to have a standard for float/int boxing ?

Monkey

Namespace difference.geom #rem monkeydoc Convenience type alias for Vec1\<Int\>. #end Alias Vec1i:Vec1<Int> #rem monkeydoc Convenience type alias for Vec1\<Float\>. #end Alias Vec1f:Vec1<Float> #rem monkeydoc The Vec1 type provides support for 2 component vectors. #end Struct Vec1<T> #rem monkeydoc Vector x coordinate. #end Field x:T #rem monkeydoc Creates a new vector. #end Method New() End Method New( t:T ) x=t End Method New( x:T,y:T ) Self.x=x End #rem monkeydoc Converts the vector to a vector of a different type. #end Operator To<C>:Vec1<C>() Return New Vec1<C>( x ) End #rem monkeydoc Converts the vector to a printable string. #end Operator To:String() Return "Vec1("+x+")" End #rem monkeydoc The X coordinate of the vector. #end Property X:T() Return x Setter( x:T ) Self.x=x End #rem monkeydoc Negates the vector components and returns the result. #end Operator-:Vec1() Return New Vec1( -x ) End #rem monkeydoc Multiplies the vector by another vector and returns the result. #end Operator*:Vec1( v:Vec1 ) Return New Vec1( x*v.x ) End #rem monkeydoc Divides the vector by another vector and returns the result. #end Operator/:Vec1( v:Vec1 ) Return New Vec1( x/v.x ) End #rem monkeydoc Adds another vector to the vector and returns the result. #end Operator+:Vec1( v:Vec1 ) Return New Vec1( x+v.x ) End #rem monkeydoc Subtracts another vector from the vector and returns the result. #end Operator-:Vec1( v:Vec1 ) Return New Vec1( x-v.x ) End #rem monkeydoc Scales the vector by a value and returns the result. #end Operator*:Vec1( s:Double ) Return New Vec1( x*s ) End #rem monkeydoc Inverse scales the vector by a value and returns the result. #end Operator/:Vec1( s:Double ) Return New Vec1( x/s ) End #rem monkeydoc Adds a value to the vector components and returns the result. #end Operator+:Vec1( s:T ) Return New Vec1( x+s ) End #rem monkeydoc Subtracts a value from the vector components and returns the result. #end Operator-:Vec1( s:T ) Return New Vec1( x-s ) End #rem monkeydoc The length of the vector. #end Property Length:Double() Return x End #rem monkeydoc The normal to the vector. #end ' #rem monkeydoc Computes the dot product of the vector with another vector. ' #end ' Method Dot:Double( v:Vec1 ) ' Return x*v.x+y*v.y ' End #rem monkeydoc Computes the distance from this vector to another. #end Method Distance:Double( v:Vec1 ) Return v.x - x End #rem monkeydoc Normalizes the vector and returns the result. #end Method Normalize:Vec1() Return Self/Length End #rem monkeydoc Blends the vector with another vector and returns the result. #end Method Blend:Vec1( v:Vec1,alpha:Double ) Return New Vec1( (v.x-x)*alpha+x ) End #rem monkeydoc Gets a string representation for the vector. #end Method ToString:String() Return Self End End '#rem monkeydoc Transforms a Vec1\<Int\> by an AffineMat3. '#end 'Function TransformVec1i<T>:Vec1i( vec:Vec1i,matrix:AffineMat3<T> ) ' ' Local tmp:=matrix * New Vec1<T>( rect.min.x ) ' ' Return New Vec1i( Round( tmp.x ),Round( tmp.y ) ) 'End

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Namespace difference.geom   #rem monkeydoc Convenience type alias for Vec1\<Int\>. #end Alias Vec1i:Vec1<Int>   #rem monkeydoc Convenience type alias for Vec1\<Float\>. #end Alias Vec1f:Vec1<Float>   #rem monkeydoc The Vec1 type provides support for 2 component vectors. #end Struct Vec1<T>   #rem monkeydoc Vector x coordinate. #end Field x:T #rem monkeydoc Creates a new vector. #end Method New() End Method New( t:T ) x=t End Method New( x:T,y:T ) Self.x=x End #rem monkeydoc Converts the vector to a vector of a different type. #end Operator To<C>:Vec1<C>() Return New Vec1<C>( x ) End   #rem monkeydoc Converts the vector to a printable string. #end Operator To:String() Return "Vec1("+x+")" End   #rem monkeydoc The X coordinate of the vector. #end Property X:T() Return x Setter( x:T ) Self.x=x End #rem monkeydoc Negates the vector components and returns the result. #end Operator-:Vec1() Return New Vec1( -x ) End #rem monkeydoc Multiplies the vector by another vector and returns the result. #end Operator*:Vec1( v:Vec1 ) Return New Vec1( x*v.x ) End   #rem monkeydoc Divides the vector by another vector and returns the result. #end Operator/:Vec1( v:Vec1 ) Return New Vec1( x/v.x ) End   #rem monkeydoc Adds another vector to the vector and returns the result. #end Operator+:Vec1( v:Vec1 ) Return New Vec1( x+v.x ) End #rem monkeydoc Subtracts another vector from the vector and returns the result. #end Operator-:Vec1( v:Vec1 ) Return New Vec1( x-v.x ) End #rem monkeydoc Scales the vector by a value and returns the result. #end Operator*:Vec1( s:Double ) Return New Vec1( x*s ) End #rem monkeydoc Inverse scales the vector by a value and returns the result. #end Operator/:Vec1( s:Double ) Return New Vec1( x/s ) End #rem monkeydoc Adds a value to the vector components and returns the result. #end Operator+:Vec1( s:T ) Return New Vec1( x+s ) End #rem monkeydoc Subtracts a value from the vector components and returns the result. #end Operator-:Vec1( s:T ) Return New Vec1( x-s ) End #rem monkeydoc The length of the vector. #end Property Length:Double() Return x End   #rem monkeydoc The normal to the vector. #end   ' #rem monkeydoc Computes the dot product of the vector with another vector. ' #end ' Method Dot:Double( v:Vec1 ) ' Return x*v.x+y*v.y ' End #rem monkeydoc Computes the distance from this vector to another. #end Method Distance:Double( v:Vec1 ) Return v.x - x End #rem monkeydoc Normalizes the vector and returns the result. #end Method Normalize:Vec1() Return Self/Length End #rem monkeydoc Blends the vector with another vector and returns the result. #end Method Blend:Vec1( v:Vec1,alpha:Double ) Return New Vec1( (v.x-x)*alpha+x ) End #rem monkeydoc Gets a string representation for the vector. #end Method ToString:String() Return Self End   End   '#rem monkeydoc Transforms a Vec1\<Int\> by an AffineMat3. '#end 'Function TransformVec1i<T>:Vec1i( vec:Vec1i,matrix:AffineMat3<T> ) ' ' Local tmp:=matrix * New Vec1<T>( rect.min.x ) ' ' Return New Vec1i( Round( tmp.x ),Round( tmp.y ) ) 'End

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