[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Z] valid_type opcode van der Sanden, Hugo variables $ sigil % sigil 2nd @ sigil 2nd hypothetical Parrot interpreter and placeholder vector operators vers opcode void context |