NB: one can put multiple statements into an `edit`. E.g. when editing a we can do:
which will set a to 5 and b to 10
If the value of an `edit` in the editor has a syntax error, the remaining statements are not evaluated and there is no error message given.
E.g. when editing a:
a will take on its new value while b would stick with its old value despite no error message.
E.g. reversing the order for the syntax error when editing a:
neither a nor b will take on new values, nor is there an error message.