Hello,
Just wondering if there is a Auto Complete feature w/ a fixed vocabulary in Dopus? Just a thought I had while renaming
No... nothing that would actually help you while in rename mode as like it seems you're asking for.
The only area of Opus that I recall having any sort of auto-complete functionality is 'path' related items... like system path variables with % characters, and Opus folder aliases.
I think the "usual" sort of answer to giving you something that might help you achieve the "result" you might want - albeit in a different manner... would be to setup various rename presets with your "fixed vocabulary" oriented renames, and then use buttons, hotkeys, and maybe dlgchoose/dlgstring menus to select from.
That said, I VERY often find myself wanting more auto-complete features in Opus throughout different areas of the program... but oddly enough, have never translated that want into an ACTUAL feature request 
. Personally, I'd REALLY like it in the command editors for buttons, hotkeys, etc... where even though we have the command, argument, and modifiers "drop-down" selection menus, I usually know "sort of" what I'm trying to do and would rather the command editor window be able to give me auto-complete suggestions instead of having to go through the menus... Ditto for the same in the FAYT field for things 'other' than folder aliases...
What you're asking for seems like it might be of interest to others - not sure if I would use it personally though... I tend to make pretty good use of rename presets combined with or replaced by rename commands with dlgstring prompts pre-filled with 'common rename substrings' that I use alot... For instance, you can probably do alot of what it sounds like you might want to do by binding a hotkey that runs a rename command with a combination of dlgchoose (to select from common substrings you want to be part of your "fixed vocab") and dlgstring prompts (for free form strings).
The things I imagine most ppl would probably not like about this method would be that to "update" your fixed vocabulary, you would need to make changes to the dlgchoose arguments (beyond just adding strings to some list in prefs, or have complimented by some 'auto-favorites' type rename learning/history system), and the dialog would have "everything" displayed in one big drop-down as opposed to being more "contextually sensitive" to whatever part of a substring you might type first - like how most "auto-complete" features behave... Which means you might end up spending more clicks or brain-power scrolling through your list than a real a-c would allow for. Also, it wouldn't be "inline" like most a-c features behave either - it would be in the form of popup dialogs...
</random_thoughts>