The code editor has basically 2 modes: Free-Form Mode and Structure Mode. Pressing the Esc key toggles between these 2 modes. Pressing the question mark (?) enters a 3rd mode: Code Menu Mode, in which a menu of available context-sensitive options is displayed. Selecting an option may bring up another, lower-level menu, which may lead to yet another lower-level menu, and so on.
Another feature of the code editor is the ability to toggle between infix and prefix modes (prefix is the default). With infix mode, binary operators come in-between their operands, while in prefix mode, all operators come before their operands. When infix mode is selected, Structure Mode is (possibly) unavailable.
Structure Mode Commands
A bottom-level token (e.g. a keyword, identifier, operator, or constant) or an entire list is often highlighted. Using the Shift key in conjunction with the Up/Down Arrow keys, it is possible to select more than one token/list at a time.
· Esc – toggle between Free Form and Structure Editor modes
· Up Arrow - go to previous list element
· Down Arrow - go to next list element
· Left Arrow - go to parent list
· Right Arrow - go to first child element (if none, display text cursor following current bottom-level token)
· Shift+Up/Down Arrow - select a range of tokens/lists
· Printable Char. - incrementally select valid matching menu item (if any)
· Backspace - undo insertion of previous printable char.
· Delete - delete current token/list
· Enter - display text cursor, insert space after cursor (or insert result of incremental menu selection)
· Space - display text cursor, insert space before cursor (or insert result of incremental menu selection)
· Ctrl+Enter – if at end of line, append blank line (otherwise break line into 2 lines)