Bash completion: compgen a wordlist as if they were paths - Only suggest up until next slash

Question 1

I've solved this.

The trick was to use compopt -o filename and then slice off the portion of the path being completed that is a sub-directory of the directory being completed.

Here's the code

# Do completion from a passed list of paths
#
# Accepts 2 arguments
# 1. The list of paths to complete from
# 2. The current word being completed
__dots_path_comp()
{
    # This forces readline to only display the last item separated by a slash
    compopt -o filenames

    local IFS=$'\n'
    local k="${#COMPREPLY[@]}"

    for path in $(compgen -W "$1" -- $2)
    do
        local trailing_trim

        # Determine what to trim from the end
        trailing_trim="${path#${2%/*}/}/"
        trailing_trim="${trailing_trim#*/}"
        trailing_trim="${trailing_trim%/}"

        # Don't add a space if there is more to complete
        [[ "$trailing_trim" != "" ]] && compopt -o nospace

        # Remove the slash if mark-directories is off
        if ! _rl_enabled mark-directories
        then
            # If The current typed path doesnt have a slash in it yet check if
            # it is the full first portion of a path and ignore everything after
            # if it is. We don't have to do this once the typed path has a slash
            # in it as the logic above will pick up on it
            [[ "$2" != */* && "$path" == ${2}/* ]] && path="$2/$trailing_trim"    

            trailing_trim="/$trailing_trim"
        fi

        COMPREPLY[k++]="${path%%${trailing_trim}}"
    done
}

Question 2

A dirty hack would be to replace your $(dots files) with

$(dots files | sed 's,/.*/,,' | uniq)

so that the full thing would read as

COMPREPLY=( $(compgen -W "$(dots files | sed 's,/.*/,,' | uniq)" -- "$cur") )

Now I personally don't like this approach very much. Instead, could you modify your script to accept, e.g., a basedirs statement that will output just what's needed?

Besides, you should be aware that the completion will not work as expected if there are spaces or other funny symbols in the names.

Question 3

I think you can get what you need with complete's -F argument. From the docs:

Any function specified with -F is invoked first. The function may use any of the shell facilities, including the compgen and compopt builtins described below (see Programmable Completion Builtins), to generate the matches. It must put the possible completions in the COMPREPLY array variable.

So, something like this to set it up:

complete -F _dots_complete dots

Then your function:

function _dots_complete {
    # your filtering logic to calculate the results array
    COMPREPLY=( "${results[@]}" )
}

In your function $1 is position of current word, $2 .. $n are the words themselves.