Comments

In ASCEND syntax, comments can be written within the special delimiters (* and *).

Example:

(*
    This model is very useless, because it doesn't have
    any equations in it yet.
*)
MODEL mymodel;
    d IS_A distance; (* pipe diameter *)
    h IS_A distance; (* change in height *)
END mymodel;

Comments can be nested (note that in some text-editors, this can confuse the syntax highlighting, but it still works fine in ASCEND). This can be useful, in particular, for temporarily removing parts of the model, e.g. during testing/debugging.

MODEL mymodel;
    d IS_A distance; (* pipe diameter *)
    (* h IS_A distance; (* change in height *) --we don't need this any more *)
END mymodel;