Null default float parameters?

Here is what I want:

vec3(1,2,3)

Creates a vector with:

x=1.0
y=2.0
z=3.0

vec3(4.0)

Creates a vector with:

x=4.0
y=4.0
z=4.0

Is there any way this can be done?:

Function Vec3:TVec3(x#=0.0,y#=Nan,z#=Nan)
Local t:TVec2=New TVec2
If IsNan(y) y=x
If IsNan(z) z=y
t.x=x
t.y=y
t.z=z
Return t
EndFunction

Function Vec3:TVec3(x#=0.0,y#=Null,z#=Null)
	Local t:TVec3=New TVec3
		If y = Null y=x
		If z = null z=y
		t.x=x
		t.y=y
		t.z=z
	Return t
EndFunction 

Local a:TVec3 = Vec3(4) 
Print a.x
Print a.y
Print a.z

Type TVec3
	Field X:Float
	Field Y:Float
	Field Z:Float
End Type

?

Perturbatio, Null is Just zero for ints/float ect.

AFAIK its not possible as things stand ATM, this is the best I can come up with to fake it....

SuperStrict 

Local Vec:TVec3 = TVec3.Create(4.0)
Print Vec.ToString()

Type TVec3

	Const Nill# = %01111111111111111111111111111111

	Field x:Float, y:Float, z:Float

	Function Create:TVec3(x#=0.0,y#=nill,z#=nill)
		Local t:TVec3=New TVec3
		t.x=x
		t.y=y
		t.z=z
		If y=nill
			t.y=x
			t.z=x
		EndIf
		Return t
	EndFunction

	Method ToString$()
		Return x+", "+y+", "+z
	EndMethod

EndType

It defines Nill as the largest possible float, which is far from ideal.

Is there some way that NaN can be brought in from C?

Weird, isNan() doesn't seem to work, but 'if x=Nan' works as expected. Just replace isNan() with a direct comparison.

actually would be better to define Nill as infinity...

	Const Nill# = 10^39

John, AFAIK Nan is also just zero

0.0/0.0 could be used.

Function Vec3:TVec3(x#=0.0,y#=0.0/0.0,z#=0.0/0.0)
	Local t:TVec2=New TVec2
	If IsNan(y) y=x
	If IsNan(z) z=y
	t.x=x
	t.y=y
	t.z=z
	Return t
EndFunction