Menu selections are handled by the ACCEPT statement. Generally speaking, a menu selection acts much like a function key. Each menu item causes an ACCEPT statement to terminate, returning an exception value equal to the item's ID.
For example, suppose the menu has this definition:
menu main-menu
"&File", 0, submenu
"&New", 101
"&Open", 102
"&Save", 103
"Save &As...", 104
separator
"E&xit", 105
end-menu
"&Options", 0, submenu
"&Save Settings on Exit", 201, checked
"&Password Protect", 202, checked
"&Confirm Deletions", 203
end-menu
If the user selected the New menu item, any executing ACCEPT statement would terminate with an exception status of 101.