[BMAX] - Generics, Function References, Boxing, Type Extension

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Pixel_Outlaw	Created : 18 June 2025 Edited : 18 June 2025 [BMAX] - Generics, Function References, Boxing, Type Extension
You will need BlitzMax NG for this. This shows how to extend a Type in Blitzmax and add additional interfaces using function references. I would have papered over the superclass' methods but BlitzMax wasn't having the method signature change... It also shows off how to use class generics. Finally, I turn what would be 2 for loops into a single chained command using the new more functional interfaces. I've been sick and tired trying to hunt down some of these features on the missing documentation so I've done so here in 1 example. SuperStrict Rem This is a little demo of 1. Extending Types 2. Using Templated Types 3. Boxing and unboxing data 4. Calling functions as parameters End Rem ' This is a Box, it can containe ~ a n y t h i n g ~ ' it is Generic (the <T> stuff) Type Box<T> Field value:T Method New(o:T) value = o End Method End Type ' This is an extension of TObjectList ' It provides some nice boxing interfaces with 'RB' prefix ' This is NOT a FULL extension. ' for THIS demo only Type RBList<T> Extends TObjectList Method RBaddLast(o:T) addLast(New Box<T>(o)) End Method Method RBFirst:T() ' we provide an unboxing First() Return Box<T>(Super.first()).value End Method Method RBGetLast:T() ' We provide an unboxing GetLast() Return Box<T>(Super.last()).value End Method Method RBValueAtIndex:T(index:Int) ' We provide an unboxing ValueAtIndex() Return Box<T>(Super.ValueAtIndex(index)).value End Method Method RBMap:RBList<T>(func:T(n:T)) ' takes a function that takes a T and returns a T ' applies to all elements updating them ' it returns itself to optionally chain For Local b:Box<T> = EachIn Self b.value = func(b.value) Next Return Self End Method Method RBDoAll:RBList<T>(func(n:T)) ' takes a parameter that eats a T ' calls it over the collection ' does not mutate elements ' it returns itself to optionally chain For Local b:Box<t> = EachIn Self func(b.value) Next Return Self End Method End Type ' Finally a collection that takes and returns ANYTHING (this was obnoxious for numbers prior) Local myList:RBList<Double> = New RBList<Double> ' Load the RBList with 10 doubles (even this could be abstracted) For Local n:Double = 0 To 9 myList.RBAddLast(n) Next ' Some fun functions to do stuff Function excitedPrint(n:Double) Print "Oh wow! Got: " + n End Function Function dbl:Double(n:Double) Return n * n End Function ' Now, in 1 line we double the entire list and print it ... ' This works because we can keep chaining ' We have killed TWO for loops here by calling functions as parameters myList.RBMap(dbl).RBDoAll(excitedPrint) ' Now let us try with common strings to show it works with objects too ' Since we have string functions built in, no accessory functions needed Local otherList:RBList<String> = New RBList<String> For Local i:String = EachIn [" foo", "bar ", " baz ", " qux ", "quux"] otherList.RBAddLast(i) Next ' Trim then Uppercase all strings in the collection then print em! ' This is to prove a technique so not the most efficent route otherlist.RBMap(Trim).RBMap(Upper).RBDoAll(Print) --v

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[BMAX] - Generics, Function References, Boxing, Type Extension

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