%skillAffectAdd()

    Applies the affect described by @skill to the given @target. The @skill
    may either be the name of the skill ("detect invisible") or it may be the
    ID of the skill. The @location describes what type of stat the affect
    modifies. The following locations are recognized:

        abilities           hurtStealth             savePrayer
        ac                  immune                  saveRod
        age                 intelligence            saveSpell
        charisma            level                   sex
        class               mana                    skill
        constitution        manaRegen               spell
        damage              manaUpkeep              strength
        damroll             material                striking
        dexterity           moves                   susceptable
        eatSpell            movesRegen              thac0
        experience          movesUpkeep             thaco
        gold                pairedWeapon            timer
        height              rent                    visible
        hitroll             resistant               weaponSpell
        hits                saveAll                 weight
        hitsRegen           saveBreath              wisdom
        hitsUpkeep          saveParalyze
        hurtArcana          savePetrify             NONE

    The @modifier denotes the amount by which to modify the given location.
    For instance the @location might be set to strength and the @modifier set
    to 2 which would increase the target's strength by 2 points for the given
    @duration. The @duration parameter should be set to the number of in game
    hours (ticks) that the affect should last. The final, optional parameter,
    @flags can be set to the name of a boolean affect, or alternatively to an
    array whose values are names of boolean affects. The following boolean
    affect names are recognized:

        anti magic              feeble mind         mana shield
        bash                    feign death         move impaired
        blindness               fiery vortex        poison
        charm                   fists of fury       protection from evil
        chill touch             fly                 regenerate
        curse                   follow              sanctuary
        deadly poison           glamorie            sense life
        death's door            half hp regen       shide
        detect evil             half mana regen     shocking grasp
        detect invisibility     half move regen     sickness
        detect magic            hide                silence
        dominated               infravision         sleep
        double hp regen         insanity            snare
        double mana regen       invisibility        sneak
        double move regen       invulnerability     water breath
        fear                    lich touch          water walk

    Sometimes you will only want to have a boolean affect like "fly" or
    "infravision". In these case you can set the @location value to NONE, and
    the modifier to 0. Note that this function only applies affects defined by
    the traditional internal affect system.

    Example 1:
    --------------------------------------------------------------------------

    //
    // Affect the @target with "bless" spell which provides +1 to hitroll
    // and enables them to "detect evil" for 6 hours (ticks).
    //

    %skillAffectAdd( @target, bless, hitroll, 1, 6, "detect evil" )


    Example 2:
    --------------------------------------------------------------------------

    //
    // Affect the @target with "bless" spell which provides ability to "sense
    // life", "detect evil", "detect magic", "detect invisibility", and
    // "infravision" for 10 hours (ticks).
    //

    @bits->1 = "sense life"
    @bits->2 = "detect evil"
    @bits->3 = "detect invisibility"
    @bits->4 = "detect magic"
    @bits->5 = "infravision"

    %skillAffectAdd( @target, "bless", NONE, 0, 10, @bits )