Function pick_nasty

src/wizard.c:537–581

also used by newcham() */

/* also used by newcham() */
int
pick_nasty(
    int difcap) /* if non-zero, try to make difficulty be lower than this */
{
    int alt, res = ROLL_FROM(nasties);

    /* To do?  Possibly should filter for appropriate forms when
     * in the elemental planes or surrounded by water or lava.
     *
     * We want monsters represented by uppercase on rogue level,
     * but we don't try very hard.
     */
    if (Is_rogue_level(&u.uz)
        && !('A' <= monsym(&mons[res]) && monsym(&mons[res]) <= 'Z'))
        res = ROLL_FROM(nasties);

    /* if genocided or too difficult or out of place, try a substitute
       when a suitable one exists
           arch-lich -> master lich,
           master mind flayer -> mind flayer,
       but the substitutes are likely to be genocided too */
    alt = res;
    if ((svm.mvitals[res].mvflags & G_GENOD) != 0
        || (difcap > 0 && mons[res].difficulty >= difcap)
         /* note: nasty() -> makemon() ignores G_HELL|G_NOHELL;
            arch-lich and master lich are both flagged as hell-only;
            this filtering demotes arch-lich to master lich when
            outside of Gehennom (unless the latter has been genocided) */
        || (mons[res].geno & (Inhell ? G_NOHELL : G_HELL)) != 0)
        alt = big_to_little(res);
    if (alt != res && (svm.mvitals[alt].mvflags & G_GENOD) == 0) {
        const char *mnam = mons[alt].pmnames[NEUTRAL],
                   *lastspace = strrchr(mnam, ' ');

        /* only non-juveniles can become alternate choice */
        if (strncmp(mnam, "baby ", 5)
            && (!lastspace
                || (strcmp(lastspace, " hatchling")
                    && strcmp(lastspace, " pup")
                    && strcmp(lastspace, " cub"))))
            res = alt;
    }

    return res;
}

/* create some nasty monsters, aligned with the caster or neutral; chaotic
   and unaligned are treated as equivalent; if summoner is Null, this is