Lines of code preceded by an identifying string or integer are said to be labeled. Statement labels are used to mark a line of code to identify it for use with statements such as GoTo or GoSub.

Labels may be valid identifier, such as those that identify programming elements. 
A label must appear at the beginning of a line of source code and must be followed by a colon, regardless of whether it is followed by a statement on the same line.
The compiler identifies labels by checking whether the beginning of the line matches any already-defined identifier. If it does not, the compiler assumes it is a label.
Labels have their own declaration space and do not interfere with other identifiers.


repeat: ' <- label
  Print “Hello World Forever”
  GoTo repeat