# Invoke tab-completion script to be sourced with Bash shell.
# Known to work on Bash 3.x, untested on 4.x.

_complete_{binary}() {{
    local candidates

    # COMP_WORDS contains the entire command string up til now (including
    # program name).
    # We hand it to Invoke so it can figure out the current context: spit back
    # core options, task names, the current task's options, or some combo.
    candidates=`{binary} --complete -- ${{COMP_WORDS[*]}}`

    # `compgen -W` takes list of valid options & a partial word & spits back
    # possible matches. Necessary for any partial word completions (vs
    # completions performed when no partial words are present).
    #
    # $2 is the current word or token being tabbed on, either empty string or a
    # partial word, and thus wants to be compgen'd to arrive at some subset of
    # our candidate list which actually matches.
    #
    # COMPREPLY is the list of valid completions handed back to `complete`.
    COMPREPLY=( $(compgen -W "${{candidates}}" -- $2) )
}}


# Tell shell builtin to use the above for completing our invocations.
# * -F: use given function name to generate completions.
# * -o default: when function generates no results, use filenames.
# * positional args: program names to complete for.
complete -F _complete_{binary} -o default {spaced_names}

# vim: set ft=sh :