Trouble accessing field within a type

Field _shapeSet:TShape[16]

Function _SetShape(ShapeToSet:TShape, ShapeString:String[])
Rem
Given four strings of length 4 characters each, where a . stands for an empty space and a * for a
bit, we can easily set a shape.
EndRem
Local stringIndex:Int, characterIndex:Int

For stringIndex = 0 To 3
For characterIndex = 0 To 3
If ShapeString[stringIndex][characterIndex] = "." Then
Else
End If
Next
Next
End Function

Function SetDefaultShapes()
Local ShapeString:String[3]
ShapeString[0] = "****"
ShapeString[1] = "...."
ShapeString[2] = "...."
ShapeString[3] = "...."
_shapeSet[0] = New TShape
_SetShape(_shapeSet[0], ShapeString)
End Function
I get an error: _shapeSet[0] = New TShape saying the identifier shapeSet cannot be found. Why can't I access a field of a type within a function? Is there any way I can tag a field as shared?

Because even though it is declared inside the type, SetDefaultShapes is just a regular function. _shapeSet is field, meaning it belongs to an object of type TShape (and is not just global variable).

In short, make it a method if you really want tro have one "_shapeSet" per object. If on the other hand you want one single global _shapeSet, then declare _shapeSet as global (replacing "field" by "global").

Thanks! It works, I think my confusion was more because TShapes (The type that contains the above code) HAS to be a single instance, ie a program with TSHapes can have only one TShape object.