This helpful feature analyses your text in the visible scope and suggests to complete a word with a keyword, class name, method or variable. So doing, the prototype is highlighted in the source code.

To expand a string at caret to an existing word
  1. Type the initial string.
  2. Do one of the following:
    • On the main menu, choose Code | Completion | Cyclic Expand Word.
    • Press ⌥/ or ⌥/⌥/ or ⌥/⌃. or ⌃.⌥ Slash, ⌥/ or ⌥/⌥ Slash, ⌥/ or ⌥/.
    The editor shows the first suggested value.
  3. Press ⏎ or ⏎⏎ or ⏎⏎ or ⏎Enter, ⏎ or ⏎Enter, ^ M, ⏎, ⌃M, ⏎ or ⌃M to accept the suggested word, or continue pressing ⌥/ or ⌥/⌥/ or ⌥/⌃. or ⌃.⌥ Slash, ⌥/ or ⌥/⌥ Slash, ⌥/ or ⌥/ until the desired word is found.

Example:

expandWord2.png

expandWord1.png