Array declarations. When the var handler sees : [N] in the type position, allocate N x 8 bytes from the heap (starting at address 300000). The variable's value is the base address. Parse and accept = undefined (ignore it -- our heap is zeroed). Accept any type name after ] (not just i64 -- also usize, bool, etc., all treated as i64).

Track which variables are arrays with a parallel flag. Set during declaration, check during indexing.