# Hillel Wayne - Procedures and Macros :: Learn TLA+ (Highlights)  ## Highlights - Macros are the general catch-all code inliner. - they can’t have labels, multiple assignments, while loops, etc. - Macros must be defined after any `define` block and before any processes. - This cannot be \in, only = - The return just ends the procedure. - a procedure can have internal variables. Two, you can have labels in them. - you have to explicitly use `call Name(val1, ...);`, and the following line must be a label or a `return` - If you want to use procedures you *must* `EXTEND Sequences`. - Procedures must be defined after any macros and before any processes. - Macros are faster and less complicated. If you can use them, use them. Use procedures when you have multiple separate processes that can do the same actions. - The `define` block has to come before any macros, which has to come before any procedures, which has to come before any processes.