Parameters for subcommands do not have spaces

[mpldr]

Given the following grammar:

aerc [<OPTION>]...;
aerc [<OPTION>]... mbox:<PATH>;
aerc [<OPTION>]... mailto:<MAILTOLINK>;
aerc [<OPTION>]... :<COMMAND>;

# shortened for brevity

<COMMAND> ::= (help <topic> | man <topic>) "show help page inside aerc"
	# shortened for brevity
	| (quit <QUIT_ARGS> | exit <QUIT_ARGS> | q <QUIT_ARGS>) "exit aerc"
	| (redraw) "force a full redraw of the screen"
	;

<QUIT_ARGS> ::= ( -f) "force close aerc"
	;

The completion looks like this:

https://asciinema.org/a/YXLgujQoQ1MkMyiS2HT8fzNGK

My (uneducated) guess would be that spaces in ()-groups are trimmed, but not just at the start and end, but also in-between.

[adaszko]

Hi and thanks for reporting.

So the problem is aerc :quit<TAB> completes to aerc :quit-f whereas you expect it to complete to aerc :quit<SPACE>? Is that right?

If that's the case, the grammar can be further simplified to:

aerc :<COMMAND>;
<COMMAND> ::= quit -f;

What's happening here is the in first line (aerc :<COMMAND>), because there's no space between : and <COMMAND>, you're telling complgen that the entirety of :<COMMAND> is going to be just a single shell word (!) This is what's called subword mode and it propagates recursively downward to all <NONTERMINAL>s. That propagation includes ignoring the space in quit -f, which is actually expected behavior.

For :quit to be completed as an entire word, you need to lift it up in the grammar, e.g.:

aerc (:help <topic> | :man <topic>) "show help page inside aerc";
aerc (:quit <QUIT_ARGS> | :exit <QUIT_ARGS> | :q <QUIT_ARGS>) "exit aerc";
<QUIT_ARGS> ::= ( -f) "force close aerc";

What I can do to make it more obvious, is I can issue a warning/error whenever there's a suspicious space used in a subword mode.

[adaszko]

Or even more concisely:

aerc ((:help | :man) <topic>) "show help page inside aerc";
aerc ((:quit | :exit | :q) <QUIT_ARGS>) "exit aerc";
<QUIT_ARGS> ::= -f "force close aerc";

[mpldr]

Thanks, that makes sense… in this case I explicitly wanted to keep the : as its own completion as to not pollute the list too much. (essentially, everything starting with : is a command to be sent to the running instance. With there being 21 commands, this gets a bit overwhelming ._.

I assume right now that option is not a given?