Variable number of parameters for a function?

Is it possible with blitz 3d to have a variable number of parameters for my function. I thought that I saw somewhere some instructions for it, but I can't find it now.

Yes, you can make a parameter optional by specifying a default value for it.

Eg: Function MyFunction(a,b=5)

Kind of.

Basically, in your function definition, you can give some variable default parameters, like this:

Function PrintLines(Message$, howmany% = 1)
...

Notice the " = 1" assignment in the function definition. This means that if you call the function without specifying a second parameter, it will use the value 1 as the second parameter. If you do specify it, it will be whatever you sent. Here's a working code example:

PrintLines("Hello")
PrintLines("Echo", 5)

Function PrintLines(Message$, howmany% = 1)
	For i% = 1 To Abs(howmany)
		Print Message
	Next
End Function

So, as you can see, it's kind of a "variable" number of parameters, though it's not truly, since all parameters are specified one way or another, just not necessarily by you.

Note that if you have a function with default parameters, every parameter after the first default parameter must also have a default parameter. That is to say, this will not work:

Function PrintLines(Message$="", howmany%) ; <--- WON'T WORK
...

Dig it?

I was thinking more along the lines of:

Function LoadSomeBitmaps(a, ...)

where ... is any number of bitmaps. Not so much making a parameter optional, but making it possible to have an unlimited number.

No, I don't think that's possible.

Yeah, you can do it in other languages, but not Blitz. Of course there are all kinds of ways to pass in a variable amount of items into a function, they just can't be separate parameters. You could, say, put them into an array, and just keep loading bitmaps until the array value is 0 or something. But that might be just as hard as what you're probably doing now (calling the function multiple times, probably).

Thanks folks. Guess I'll find another solution.

well no you can't do it that way, but you could do:

type bitmaplist
field a.bitmap
end type

type bitmap
field bitmapfile$
end type

dim bitmaplist(1)
b (0).bitmaplist=new bitmaplist

b (0)\ a = new bitmap
b (0)\a\bitmapfile$="World"
b (0)\ a = new bitmap
b (0)\a\bitmapfile$="grass"

Loadbitmaps b

Function Loadbitmaps(b.bitmaplist)
For each b(0)\a\ bitmap
filex=b(0)\a\bitmapfile$
file=b(0)\a\bitmapfile$+".dat"
filex=Loadimage(file)
next
end function

note- not sure if i got everythign right here, but i don't have time to test it but it should work, just figure out how to run types within types, and you can use 1 identifier. I dimmed the array with the (0) just in case, but its not neccesary. Good luck, maybe someone knows how to do this better then i do.

thats prolly the best bet. but if you want to do something super dynamic, like using variants, you could always use a string or an array, and parse/use each array item

function DOWORK(myarray [])
where each item in myarray is a value of a different type

to add a twist you could make the first item in the array how the function should handle it


function dowork(myarray[])
select myarray(1)
case "DELETE PLAYER"
delete myarray(2)
case "loadplayer"
playertype = new playertype
playertype\name = myarray(2)
playertype\height = myarray(3)
playertype\weight = myarray(4)

end function