1 //: Distinguish between labels marking the start of a function, and labels
2 //: inside functions.
3 //:
4 //:   Labels within functions start with a '$', and are only permitted in
5 //:   'jump' instructions.
6 //:
7 //:   Labels marking the start of functions lack the '$' sigil, and are only
8 //:   permitted in 'call' instructions.
9