If you see a command text somewhere on the screen, you can activate it wherever you find it. Or you can enter the command text anywhere, in a the system frame for example, and then activate it wherever you have entered it For example, if you activate Desktops. Besides the proper command, Desktops. OpenDoc, the command Desktops. This additional information is a parameter for the command Desktops.
Some commands allow for a list of several parameters.
For commands using a list of variable length, Oberon needs a hint marking the end of this list. Commands can use the current selection as input area using only the selected section. Commands can also redirect the input to begin at the selection, starting there but continuing possibly beyond the selected range. There is no unified convention for this. To safeguard against unwanted risks, in particular for critical commands like file deletion, the end of the parameter list should always be marked as discussed above, in particular if redirection to current selections is used.