Showing available jam targets

[kaliber]

As I know there is no way to display available jam targets. It would be nice to have "help" target.

jam -q help

Available targets:
haiku-image
haiku-vmware-image
...

[mmu_man]

I use this as a completion function for jam, but it doesn't seem to pick all the possible targets (and it's slow):

_jam ()
{
    local cur prev jamfiles jf f jf2 ft iter targets;
    COMPREPLY=();
    cur=${COMP_WORDS[COMP_CWORD]};
    prev=${COMP_WORDS[COMP_CWORD-1]};
    if [ "$prev" = "-d" ]; then
        COMPREPLY=($( compgen -W 'a c d m x $(seq 0 9)' -- $cur ));
    else
        if [[ "$cur" == -* ]]; then
            COMPREPLY=($( compgen -W '-a \
                -da -dc -dd -dm -dx -d0 -d1 -d2 -d3 -d4 -d5 -d6 -d7 -d8 -d9 \
                -f -g -j -n -o -q -s -t -v' -- $cur ));
        else
            if [ -z "$_jam_targets_cache" ]; then
                echo -en " [building jam target cache...]\033[31D";
                _jam_targets_cache="$(jam -d 5a -n -q veryunlikelytargetonlyusedforbuildingtargetlist | grep '\(NotFile \|set targets  =\)' | sed 's/.*NotFile //;s/.*  = //;s/</\\</g;s/>/\\>/g;s/!/\\!/g')";
                echo -en "                               \033[31D";
                export _jam_targets_cache;
            fi;
            COMPREPLY=($( compgen -W "$_jam_targets_cache" -- $cur ));
        fi;
    fi;
    return 0
}

[emitrax]

How about a static list instead of generating it at runtime?