Give feedback just before timed levitation runs out

[aNetHack.git] / src / pager.c

/* NetHack 3.6  pager.c $NHDT-Date: 1471112245 2016/08/13 18:17:25 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.112 $ */
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
/* NetHack may be freely redistributed.  See license for details. */

/* This file contains the command routines dowhatis() and dohelp() and */
/* a few other help related facilities */

#include "hack.h"
#include "dlb.h"

STATIC_DCL boolean FDECL(is_swallow_sym, (int));
STATIC_DCL int FDECL(append_str, (char *, const char *));
STATIC_DCL void FDECL(look_at_object, (char *, int, int, int));
STATIC_DCL void FDECL(look_at_monster, (char *, char *,
                                        struct monst *, int, int));
STATIC_DCL struct permonst *FDECL(lookat, (int, int, char *, char *));
STATIC_DCL void FDECL(checkfile, (char *, struct permonst *,
                                  BOOLEAN_P, BOOLEAN_P));
STATIC_DCL void FDECL(look_all, (BOOLEAN_P,BOOLEAN_P));
STATIC_DCL void NDECL(whatdoes_help);
STATIC_DCL void NDECL(docontact);
STATIC_DCL void NDECL(dispfile_help);
STATIC_DCL void NDECL(dispfile_shelp);
STATIC_DCL void NDECL(dispfile_optionfile);
STATIC_DCL void NDECL(dispfile_license);
STATIC_DCL void NDECL(dispfile_debughelp);
STATIC_DCL void NDECL(hmenu_doextversion);
STATIC_DCL void NDECL(hmenu_dohistory);
STATIC_DCL void NDECL(hmenu_dowhatis);
STATIC_DCL void NDECL(hmenu_dowhatdoes);
STATIC_DCL void NDECL(hmenu_doextlist);
#ifdef PORT_HELP
extern void NDECL(port_help);
#endif

/* Returns "true" for characters that could represent a monster's stomach. */
STATIC_OVL boolean
is_swallow_sym(c)
int c;
{
    int i;

    for (i = S_sw_tl; i <= S_sw_br; i++)
        if ((int) showsyms[i] == c)
            return TRUE;
    return FALSE;
}

/*
 * Append new_str to the end of buf if new_str doesn't already exist as
 * a substring of buf.  Return 1 if the string was appended, 0 otherwise.
 * It is expected that buf is of size BUFSZ.
 */
STATIC_OVL int
append_str(buf, new_str)
char *buf;
const char *new_str;
{
    int space_left; /* space remaining in buf */

    if (strstri(buf, new_str))
        return 0;

    space_left = BUFSZ - strlen(buf) - 1;
    if (space_left < 1)
        return 0;
    (void) strncat(buf, " or ", space_left);
    (void) strncat(buf, new_str, space_left - 4);
    return 1;
}

/* shared by monster probing (via query_objlist!) as well as lookat() */
char *
self_lookat(outbuf)
char *outbuf;
{
    char race[QBUFSZ];

    /* include race with role unless polymorphed */
    race[0] = '\0';
    if (!Upolyd)
        Sprintf(race, "%s ", urace.adj);
    Sprintf(outbuf, "%s%s%s called %s",
            /* being blinded may hide invisibility from self */
            (Invis && (senseself() || !Blind)) ? "invisible " : "", race,
            mons[u.umonnum].mname, plname);
    if (u.usteed)
        Sprintf(eos(outbuf), ", mounted on %s", y_monnam(u.usteed));
    if (u.uundetected || (Upolyd && youmonst.m_ap_type))
        mhidden_description(&youmonst, FALSE, eos(outbuf));
    return outbuf;
}

/* describe a hidden monster; used for look_at during extended monster
   detection and for probing; also when looking at self */
void
mhidden_description(mon, altmon, outbuf)
struct monst *mon;
boolean altmon; /* for probing: if mimicking a monster, say so */
char *outbuf;
{
    struct obj *otmp;
    boolean fakeobj, isyou = (mon == &youmonst);
    int x = isyou ? u.ux : mon->mx, y = isyou ? u.uy : mon->my,
        glyph = (level.flags.hero_memory && !isyou) ? levl[x][y].glyph
                                                    : glyph_at(x, y);

    *outbuf = '\0';
    if (mon->m_ap_type == M_AP_FURNITURE
        || mon->m_ap_type == M_AP_OBJECT) {
        Strcpy(outbuf, ", mimicking ");
        if (mon->m_ap_type == M_AP_FURNITURE) {
            Strcat(outbuf, an(defsyms[mon->mappearance].explanation));
        } else if (mon->m_ap_type == M_AP_OBJECT
                   /* remembered glyph, not glyph_at() which is 'mon' */
                   && glyph_is_object(glyph)) {
        objfrommap:
            otmp = (struct obj *) 0;
            fakeobj = object_from_map(glyph, x, y, &otmp);
            Strcat(outbuf, (otmp && otmp->otyp != STRANGE_OBJECT)
                              ? ansimpleoname(otmp)
                              : an(obj_descr[STRANGE_OBJECT].oc_name));
            if (fakeobj)
                dealloc_obj(otmp);
        } else {
            Strcat(outbuf, something);
        }
    } else if (mon->m_ap_type == M_AP_MONSTER) {
        if (altmon)
            Sprintf(outbuf, ", masquerading as %s",
                    an(mons[mon->mappearance].mname));
    } else if (isyou ? u.uundetected : mon->mundetected) {
        Strcpy(outbuf, ", hiding");
        if (hides_under(mon->data)) {
            Strcat(outbuf, " under ");
            /* remembered glyph, not glyph_at() which is 'mon' */
            if (glyph_is_object(glyph))
                goto objfrommap;
            Strcat(outbuf, something);
        } else if (is_hider(mon->data)) {
            Sprintf(eos(outbuf), " on the %s",
                    (is_flyer(mon->data) || mon->data->mlet == S_PIERCER)
                       ? "ceiling"
                       : surface(x, y)); /* trapper */
        } else {
            if (mon->data->mlet == S_EEL && is_pool(x, y))
                Strcat(outbuf, " in murky water");
        }
    }
}

/* extracted from lookat(); also used by namefloorobj() */
boolean
object_from_map(glyph, x, y, obj_p)
int glyph, x, y;
struct obj **obj_p;
{
    boolean fakeobj = FALSE;
    struct monst *mtmp;
    struct obj *otmp;
    int glyphotyp = glyph_to_obj(glyph);

    *obj_p = (struct obj *) 0;
    /* TODO: check inside containers in case glyph came from detection */
    if ((otmp = sobj_at(glyphotyp, x, y)) == 0)
        for (otmp = level.buriedobjlist; otmp; otmp = otmp->nobj)
            if (otmp->ox == x && otmp->oy == y && otmp->otyp == glyphotyp)
                break;

    /* there might be a mimic here posing as an object */
    mtmp = m_at(x, y);
    if (mtmp && is_obj_mappear(mtmp, (unsigned) glyphotyp))
        otmp = 0;
    else
        mtmp = 0;

    if (!otmp || otmp->otyp != glyphotyp) {
        /* this used to exclude STRANGE_OBJECT; now caller deals with it */
        otmp = mksobj(glyphotyp, FALSE, FALSE);
        if (!otmp)
            return FALSE;
        fakeobj = TRUE;
        if (otmp->oclass == COIN_CLASS)
            otmp->quan = 2L; /* to force pluralization */
        else if (otmp->otyp == SLIME_MOLD)
            otmp->spe = context.current_fruit; /* give it a type */
        if (mtmp && has_mcorpsenm(mtmp)) /* mimic as corpse/statue */
            otmp->corpsenm = MCORPSENM(mtmp);
    }
    /* if located at adjacent spot, mark it as having been seen up close
       (corpse type will be known even if dknown is 0, so we don't need a
       touch check for cockatrice corpse--we're looking without touching) */
    if (otmp && distu(x, y) <= 2 && !Blind && !Hallucination
        /* redundant: we only look for an object which matches current
           glyph among floor and buried objects; when !Blind, any buried
           object's glyph will have been replaced by whatever is present
           on the surface as soon as we moved next to its spot */
        && otmp->where == OBJ_FLOOR /* not buried */
        /* terrain mode views what's already known, doesn't learn new stuff */
        && !iflags.terrainmode) /* so don't set dknown when in terrain mode */
        otmp->dknown = 1; /* if a pile, clearly see the top item only */

    *obj_p = otmp;
    return fakeobj; /* when True, caller needs to dealloc *obj_p */
}

STATIC_OVL void
look_at_object(buf, x, y, glyph)
char *buf; /* output buffer */
int x, y, glyph;
{
    struct obj *otmp = 0;
    boolean fakeobj = object_from_map(glyph, x, y, &otmp);

    if (otmp) {
        Strcpy(buf, (otmp->otyp != STRANGE_OBJECT)
                     ? distant_name(otmp, doname_vague_quan)
                     : obj_descr[STRANGE_OBJECT].oc_name);
        if (fakeobj)
            dealloc_obj(otmp), otmp = 0;
    } else
        Strcpy(buf, something); /* sanity precaution */

    if (otmp && otmp->where == OBJ_BURIED)
        Strcat(buf, " (buried)");
    else if (levl[x][y].typ == STONE || levl[x][y].typ == SCORR)
        Strcat(buf, " embedded in stone");
    else if (IS_WALL(levl[x][y].typ) || levl[x][y].typ == SDOOR)
        Strcat(buf, " embedded in a wall");
    else if (closed_door(x, y))
        Strcat(buf, " embedded in a door");
    else if (is_pool(x, y))
        Strcat(buf, " in water");
    else if (is_lava(x, y))
        Strcat(buf, " in molten lava"); /* [can this ever happen?] */
    return;
}

STATIC_OVL void
look_at_monster(buf, monbuf, mtmp, x, y)
char *buf, *monbuf; /* buf: output, monbuf: optional output */
struct monst *mtmp;
int x, y;
{
    char *name, monnambuf[BUFSZ];
    boolean accurate = !Hallucination;

    name = (mtmp->data == &mons[PM_COYOTE] && accurate)
              ? coyotename(mtmp, monnambuf)
              : distant_monnam(mtmp, ARTICLE_NONE, monnambuf);
    Sprintf(buf, "%s%s%s",
            (mtmp->mx != x || mtmp->my != y)
                ? ((mtmp->isshk && accurate) ? "tail of " : "tail of a ")
                : "",
            (mtmp->mtame && accurate)
                ? "tame "
                : (mtmp->mpeaceful && accurate)
                    ? "peaceful "
                    : "",
            name);
    if (u.ustuck == mtmp) {
        if (u.uswallow || iflags.save_uswallow) /* monster detection */
            Strcat(buf, is_animal(mtmp->data)
                          ? ", swallowing you" : ", engulfing you");
        else
            Strcat(buf, (Upolyd && sticks(youmonst.data))
                          ? ", being held" : ", holding you");
    }
    if (mtmp->mleashed)
        Strcat(buf, ", leashed to you");

    if (mtmp->mtrapped && cansee(mtmp->mx, mtmp->my)) {
        struct trap *t = t_at(mtmp->mx, mtmp->my);
        int tt = t ? t->ttyp : NO_TRAP;

        /* newsym lets you know of the trap, so mention it here */
        if (tt == BEAR_TRAP || tt == PIT || tt == SPIKED_PIT || tt == WEB)
            Sprintf(eos(buf), ", trapped in %s",
                    an(defsyms[trap_to_defsym(tt)].explanation));
    }

    /* we know the hero sees a monster at this location, but if it's shown
       due to persistant monster detection he might remember something else */
    if (mtmp->mundetected || mtmp->m_ap_type)
        mhidden_description(mtmp, FALSE, eos(buf));

    if (monbuf) {
        unsigned how_seen = howmonseen(mtmp);

        monbuf[0] = '\0';
        if (how_seen != 0 && how_seen != MONSEEN_NORMAL) {
            if (how_seen & MONSEEN_NORMAL) {
                Strcat(monbuf, "normal vision");
                how_seen &= ~MONSEEN_NORMAL;
                /* how_seen can't be 0 yet... */
                if (how_seen)
                    Strcat(monbuf, ", ");
            }
            if (how_seen & MONSEEN_SEEINVIS) {
                Strcat(monbuf, "see invisible");
                how_seen &= ~MONSEEN_SEEINVIS;
                if (how_seen)
                    Strcat(monbuf, ", ");
            }
            if (how_seen & MONSEEN_INFRAVIS) {
                Strcat(monbuf, "infravision");
                how_seen &= ~MONSEEN_INFRAVIS;
                if (how_seen)
                    Strcat(monbuf, ", ");
            }
            if (how_seen & MONSEEN_TELEPAT) {
                Strcat(monbuf, "telepathy");
                how_seen &= ~MONSEEN_TELEPAT;
                if (how_seen)
                    Strcat(monbuf, ", ");
            }
            if (how_seen & MONSEEN_XRAYVIS) {
                /* Eyes of the Overworld */
                Strcat(monbuf, "astral vision");
                how_seen &= ~MONSEEN_XRAYVIS;
                if (how_seen)
                    Strcat(monbuf, ", ");
            }
            if (how_seen & MONSEEN_DETECT) {
                Strcat(monbuf, "monster detection");
                how_seen &= ~MONSEEN_DETECT;
                if (how_seen)
                    Strcat(monbuf, ", ");
            }
            if (how_seen & MONSEEN_WARNMON) {
                if (Hallucination)
                    Strcat(monbuf, "paranoid delusion");
                else
                    Sprintf(eos(monbuf), "warned of %s",
                            makeplural(mtmp->data->mname));
                how_seen &= ~MONSEEN_WARNMON;
                if (how_seen)
                    Strcat(monbuf, ", ");
            }
            /* should have used up all the how_seen bits by now */
            if (how_seen) {
                impossible("lookat: unknown method of seeing monster");
                Sprintf(eos(monbuf), "(%u)", how_seen);
            }
        } /* seen by something other than normal vision */
    } /* monbuf is non-null */
}

/*
 * Return the name of the glyph found at (x,y).
 * If not hallucinating and the glyph is a monster, also monster data.
 */
STATIC_OVL struct permonst *
lookat(x, y, buf, monbuf)
int x, y;
char *buf, *monbuf;
{
    struct monst *mtmp = (struct monst *) 0;
    struct permonst *pm = (struct permonst *) 0;
    int glyph;

    buf[0] = monbuf[0] = '\0';
    glyph = glyph_at(x, y);
    if (u.ux == x && u.uy == y && canspotself()
        && !(iflags.save_uswallow && glyph == mon_to_glyph(u.ustuck))
        && (!iflags.terrainmode || (iflags.terrainmode & TER_MON) != 0)) {
        /* fill in buf[] */
        (void) self_lookat(buf);

        /* file lookup can't distinguish between "gnomish wizard" monster
           and correspondingly named player character, always picking the
           former; force it to find the general "wizard" entry instead */
        if (Role_if(PM_WIZARD) && Race_if(PM_GNOME) && !Upolyd)
            pm = &mons[PM_WIZARD];

        /* When you see yourself normally, no explanation is appended
           (even if you could also see yourself via other means).
           Sensing self while blind or swallowed is treated as if it
           were by normal vision (cf canseeself()). */
        if ((Invisible || u.uundetected) && !Blind
            && !(u.uswallow || iflags.save_uswallow)) {
            unsigned how = 0;

            if (Infravision)
                how |= 1;
            if (Unblind_telepat)
                how |= 2;
            if (Detect_monsters)
                how |= 4;

            if (how)
                Sprintf(eos(buf), " [seen: %s%s%s%s%s]",
                        (how & 1) ? "infravision" : "",
                        /* add comma if telep and infrav */
                        ((how & 3) > 2) ? ", " : "",
                        (how & 2) ? "telepathy" : "",
                        /* add comma if detect and (infrav or telep or both) */
                        ((how & 7) > 4) ? ", " : "",
                        (how & 4) ? "monster detection" : "");
        }
    } else if (u.uswallow) {
        /* when swallowed, we're only called for spots adjacent to hero,
           and blindness doesn't prevent hero from feeling what holds him */
        Sprintf(buf, "interior of %s", a_monnam(u.ustuck));
        pm = u.ustuck->data;
    } else if (glyph_is_monster(glyph)) {
        bhitpos.x = x;
        bhitpos.y = y;
        if ((mtmp = m_at(x, y)) != 0) {
            look_at_monster(buf, monbuf, mtmp, x, y);
            pm = mtmp->data;
        }
    } else if (glyph_is_object(glyph)) {
        look_at_object(buf, x, y, glyph); /* fill in buf[] */
    } else if (glyph_is_trap(glyph)) {
        int tnum = what_trap(glyph_to_trap(glyph));

        /* Trap detection displays a bear trap at locations having
         * a trapped door or trapped container or both.
         * TODO: we should create actual trap types for doors and
         * chests so that they can have their own glyphs and tiles.
         */
        if (trapped_chest_at(tnum, x, y))
            Strcpy(buf, "trapped chest"); /* might actually be a large box */
        else if (trapped_door_at(tnum, x, y))
            Strcpy(buf, "trapped door"); /* not "trap door"... */
        else
            Strcpy(buf, defsyms[trap_to_defsym(tnum)].explanation);
    } else if (glyph_is_warning(glyph)) {
        int warnindx = glyph_to_warning(glyph);

        Strcpy(buf, def_warnsyms[warnindx].explanation);
    } else if (!glyph_is_cmap(glyph)) {
        Strcpy(buf, "unexplored area");
    } else
        switch (glyph_to_cmap(glyph)) {
        case S_altar:
            Sprintf(buf, "%s %saltar",
                    /* like endgame high priests, endgame high altars
                       are only recognizable when immediately adjacent */
                    (Is_astralevel(&u.uz) && distu(x, y) > 2)
                        ? "aligned"
                        : align_str(
                              Amask2align(levl[x][y].altarmask & ~AM_SHRINE)),
                    ((levl[x][y].altarmask & AM_SHRINE)
                     && (Is_astralevel(&u.uz) || Is_sanctum(&u.uz)))
                        ? "high "
                        : "");
            break;
        case S_ndoor:
            if (is_drawbridge_wall(x, y) >= 0)
                Strcpy(buf, "open drawbridge portcullis");
            else if ((levl[x][y].doormask & ~D_TRAPPED) == D_BROKEN)
                Strcpy(buf, "broken door");
            else
                Strcpy(buf, "doorway");
            break;
        case S_cloud:
            Strcpy(buf,
                   Is_airlevel(&u.uz) ? "cloudy area" : "fog/vapor cloud");
            break;
        case S_stone:
            if (!levl[x][y].seenv) {
                Strcpy(buf, "unexplored");
                break;
            } else if (Underwater && !Is_waterlevel(&u.uz)) {
                /* "unknown" == previously mapped but not visible when
                   submerged; better terminology appreciated... */
                Strcpy(buf, (distu(x, y) <= 2) ? "land" : "unknown");
                break;
            } else if (levl[x][y].typ == STONE || levl[x][y].typ == SCORR) {
                Strcpy(buf, "stone");
                break;
            }
            /*else FALLTHRU*/
        default:
            Strcpy(buf, defsyms[glyph_to_cmap(glyph)].explanation);
            break;
        }

    return (pm && !Hallucination) ? pm : (struct permonst *) 0;
}

/*
 * Look in the "data" file for more info.  Called if the user typed in the
 * whole name (user_typed_name == TRUE), or we've found a possible match
 * with a character/glyph and flags.help is TRUE.
 *
 * NOTE: when (user_typed_name == FALSE), inp is considered read-only and
 *       must not be changed directly, e.g. via lcase(). We want to force
 *       lcase() for data.base lookup so that we can have a clean key.
 *       Therefore, we create a copy of inp _just_ for data.base lookup.
 */
STATIC_OVL void
checkfile(inp, pm, user_typed_name, without_asking)
char *inp;
struct permonst *pm;
boolean user_typed_name, without_asking;
{
    dlb *fp;
    char buf[BUFSZ], newstr[BUFSZ], givenname[BUFSZ];
    char *ep, *dbase_str;
    unsigned long txt_offset = 0L;
    int chk_skip, pass = 1;
    boolean found_in_file = FALSE, skipping_entry = FALSE, yes_to_moreinfo;
    winid datawin = WIN_ERR;

    fp = dlb_fopen(DATAFILE, "r");
    if (!fp) {
        pline("Cannot open data file!");
        return;
    }

    /*
     * If someone passed us garbage, prevent fault.
     */
    if (!inp || (inp && strlen(inp) > (BUFSZ - 1))) {
        pline("bad do_look buffer passed!");
        return;
    }

    /* To prevent the need for entries in data.base like *ngel to account
     * for Angel and angel, make the lookup string the same for both
     * user_typed_name and picked name.
     */
    if (pm != (struct permonst *) 0 && !user_typed_name)
        dbase_str = strcpy(newstr, pm->mname);
    else
        dbase_str = strcpy(newstr, inp);
    (void) lcase(dbase_str);

    if (!strncmp(dbase_str, "interior of ", 12))
        dbase_str += 12;
    if (!strncmp(dbase_str, "a ", 2))
        dbase_str += 2;
    else if (!strncmp(dbase_str, "an ", 3))
        dbase_str += 3;
    else if (!strncmp(dbase_str, "the ", 4))
        dbase_str += 4;
    if (!strncmp(dbase_str, "tame ", 5))
        dbase_str += 5;
    else if (!strncmp(dbase_str, "peaceful ", 9))
        dbase_str += 9;
    if (!strncmp(dbase_str, "invisible ", 10))
        dbase_str += 10;
    if (!strncmp(dbase_str, "saddled ", 8))
        dbase_str += 8;
    if (!strncmp(dbase_str, "statue of ", 10))
        dbase_str[6] = '\0';
    else if (!strncmp(dbase_str, "figurine of ", 12))
        dbase_str[8] = '\0';

    /* Make sure the name is non-empty. */
    if (*dbase_str) {
        /* adjust the input to remove "named " and convert to lower case */
        char *alt = 0; /* alternate description */

        if ((ep = strstri(dbase_str, " named ")) != 0)
            alt = ep + 7;
        else if ((ep = strstri(dbase_str, " called ")) != 0) {
            if (strlen(ep + 8) < BUFSZ - 1) {
                Strcpy(givenname, ep + 8);
                givenname[BUFSZ-1] = '\0';
                alt = &givenname[0];
            }
        }
        if (!ep)
            ep = strstri(dbase_str, ", ");
        if (ep && ep > dbase_str)
            *ep = '\0';

        /*
         * If the object is named, then the name is the alternate description;
         * otherwise, the result of makesingular() applied to the name is.
         * This isn't strictly optimal, but named objects of interest to the
         * user will usually be found under their name, rather than under
         * their object type, so looking for a singular form is pointless.
         */
        if (!alt)
            alt = makesingular(dbase_str);

        if (!strcmp(alt, dbase_str))
            pass = 0;

        for (; pass >= 0; pass--) {
            txt_offset = 0L;
            if (dlb_fseek(fp, txt_offset, SEEK_SET) < 0 ) {
                impossible("can't get to start of 'data' file");
                dlb_fclose(fp);
                return;
            }
            /* skip first record; read second */
            if (!dlb_fgets(buf, BUFSZ, fp) || !dlb_fgets(buf, BUFSZ, fp)) {
                impossible("can't read 'data' file");
                (void) dlb_fclose(fp);
                return;
            } else if (sscanf(buf, "%8lx\n", &txt_offset) < 1
                       || txt_offset == 0L)
                goto bad_data_file;

            /* look for the appropriate entry */
            while (dlb_fgets(buf, BUFSZ, fp)) {
                if (*buf == '.')
                    break; /* we passed last entry without success */

                if (digit(*buf)) {
                    /* a number indicates the end of current entry */
                    skipping_entry = FALSE;
                } else if (!skipping_entry) {
                    if (!(ep = index(buf, '\n')))
                        goto bad_data_file;
                    (void) strip_newline((ep > buf) ? ep - 1 : ep);
                    /* if we match a key that begins with "~", skip
                       this entry */
                    chk_skip = (*buf == '~') ? 1 : 0;
                    if ((pass == 0 && pmatch(&buf[chk_skip], dbase_str))
                        || (pass == 1 && alt && pmatch(&buf[chk_skip], alt))) {
                        if (chk_skip) {
                            skipping_entry = TRUE;
                            continue;
                        } else {
                            found_in_file = TRUE;
                            break;
                        }
                    }
                }
            }
            if (found_in_file) {
                long entry_offset;
                int entry_count;
                int i;

                /* skip over other possible matches for the info */
                do {
                    if (!dlb_fgets(buf, BUFSZ, fp))
                        goto bad_data_file;
                } while (!digit(*buf));
                if (sscanf(buf, "%ld,%d\n", &entry_offset, &entry_count) < 2) {
                bad_data_file:
                    impossible("'data' file in wrong format or corrupted");
                    /* window will exist if came here from below via 'goto' */
                    if (datawin != WIN_ERR)
                        destroy_nhwindow(datawin);
                    (void) dlb_fclose(fp);
                    return;
                }

                yes_to_moreinfo = FALSE;
                if (!user_typed_name && !without_asking) {
                    unsigned maxt = strlen("More info about \"\"?");
                    char *entrytext = pass ? alt : dbase_str;
                    char question[BUFSZ];

                    if (strlen(entrytext) < BUFSZ - maxt) {
                        Strcpy(question, "More info about \"");
                        Strcat(question, entrytext);
                        Strcat(question, "\"?");
                    }
                    if (yn(question) == 'y')
                        yes_to_moreinfo = TRUE;
                }

                if (user_typed_name || without_asking || yes_to_moreinfo) {
                    if (dlb_fseek(fp, (long) txt_offset + entry_offset,
                                  SEEK_SET) < 0) {
                        pline("? Seek error on 'data' file!");
                        (void) dlb_fclose(fp);
                        return;
                    }
                    datawin = create_nhwindow(NHW_MENU);
                    for (i = 0; i < entry_count; i++) {
                        if (!dlb_fgets(buf, BUFSZ, fp))
                            goto bad_data_file;
                        (void) strip_newline(buf);
                        if (index(buf + 1, '\t') != 0)
                            (void) tabexpand(buf + 1);
                        putstr(datawin, 0, buf + 1);
                    }
                    display_nhwindow(datawin, FALSE);
                    destroy_nhwindow(datawin);
                }
            } else if (user_typed_name && pass == 0)
                pline("I don't have any information on those things.");
        }
    }
    (void) dlb_fclose(fp);
}

int
do_screen_description(cc, looked, sym, out_str, firstmatch)
coord cc;
boolean looked;
int sym;
char *out_str;
const char **firstmatch;
{
    static const char mon_interior[] = "the interior of a monster",
                      unreconnoitered[] = "unreconnoitered";
    static char look_buf[BUFSZ];
    char prefix[BUFSZ];
    int i, alt_i, glyph = NO_GLYPH,
        skipped_venom = 0, found = 0; /* count of matching syms found */
    boolean hit_trap, need_to_look = FALSE,
            submerged = (Underwater && !Is_waterlevel(&u.uz));
    const char *x_str;

    if (looked) {
        int oc;
        unsigned os;

        glyph = glyph_at(cc.x, cc.y);
        /* Convert glyph at selected position to a symbol for use below. */
        (void) mapglyph(glyph, &sym, &oc, &os, cc.x, cc.y);

        Sprintf(prefix, "%s        ", encglyph(glyph));
    } else
        Sprintf(prefix, "%c        ", sym);

    /*
     * Check all the possibilities, saving all explanations in a buffer.
     * When all have been checked then the string is printed.
     */

    /*
     * Handle restricted vision range (limited to adjacent spots when
     * swallowed or underwater) cases first.
     *
     * 3.6.0 listed anywhere on map, other than self, as "interior
     * of a monster" when swallowed, and non-adjacent water or
     * non-water anywhere as "dark part of a room" when underwater.
     * "unreconnoitered" is an attempt to convey "even if you knew
     * what was there earlier, you don't know what is there in the
     * current circumstance".
     *
     * (Note: 'self' will always be visible when swallowed so we don't
     * need special swallow handling for <ux,uy>.
     * Another note: for '#terrain' without monsters, u.uswallow and
     * submerged will always both be False and skip this code.)
     */
    x_str = 0;
    if (!looked) {
        ; /* skip special handling */
    } else if (((u.uswallow || submerged) && distu(cc.x, cc.y) > 2)
               /* detection showing some category, so mostly background */
               || ((iflags.terrainmode & (TER_DETECT | TER_MAP)) == TER_DETECT
                   && glyph == cmap_to_glyph(S_stone))) {
        x_str = unreconnoitered;
        need_to_look = FALSE;
    } else if (is_swallow_sym(sym)) {
        x_str = mon_interior;
        need_to_look = TRUE; /* for specific monster type */
    }
    if (x_str) {
        /* we know 'found' is zero here, but guard against some other
           special case being inserted ahead of us someday */
        if (!found) {
            Sprintf(out_str, "%s%s", prefix, x_str);
            *firstmatch = x_str;
            found++;
        } else {
            found += append_str(out_str, x_str); /* not 'an(x_str)' */
        }
        /* for is_swallow_sym(), we want to list the current symbol's
           other possibilities (wand for '/', throne for '\\', &c) so
           don't jump to the end for the x_str==mon_interior case */
        if (x_str == unreconnoitered)
            goto didlook;
    }

    /* Check for monsters */
    if (!iflags.terrainmode || (iflags.terrainmode & TER_MON) != 0) {
        for (i = 0; i < MAXMCLASSES; i++) {
            if (sym == (looked ? showsyms[i + SYM_OFF_M] : def_monsyms[i].sym)
                && def_monsyms[i].explain) {
                need_to_look = TRUE;
                if (!found) {
                    Sprintf(out_str, "%s%s",
                            prefix, an(def_monsyms[i].explain));
                    *firstmatch = def_monsyms[i].explain;
                    found++;
                } else {
                    found += append_str(out_str, an(def_monsyms[i].explain));
                }
            }
        }
        /* handle '@' as a special case if it refers to you and you're
           playing a character which isn't normally displayed by that
           symbol; firstmatch is assumed to already be set for '@' */
        if ((looked ? (sym == showsyms[S_HUMAN + SYM_OFF_M]
                       && cc.x == u.ux && cc.y == u.uy)
                    : (sym == def_monsyms[S_HUMAN].sym && !flags.showrace))
            && !(Race_if(PM_HUMAN) || Race_if(PM_ELF)) && !Upolyd)
            found += append_str(out_str, "you"); /* tack on "or you" */
    }

    /* Now check for objects */
    if (!iflags.terrainmode || (iflags.terrainmode & TER_OBJ) != 0) {
        for (i = 1; i < MAXOCLASSES; i++) {
            if (sym == (looked ? showsyms[i + SYM_OFF_O]
                               : def_oc_syms[i].sym)
                || (looked && i == ROCK_CLASS && glyph_is_statue(glyph))) {
                need_to_look = TRUE;
                if (looked && i == VENOM_CLASS) {
                    skipped_venom++;
                    continue;
                }
                if (!found) {
                    Sprintf(out_str, "%s%s",
                            prefix, an(def_oc_syms[i].explain));
                    *firstmatch = def_oc_syms[i].explain;
                    found++;
                } else {
                    found += append_str(out_str, an(def_oc_syms[i].explain));
                }
            }
        }
    }

    if (sym == DEF_INVISIBLE) {
        if (!found) {
            Sprintf(out_str, "%s%s", prefix, an(invisexplain));
            *firstmatch = invisexplain;
            found++;
        } else {
            found += append_str(out_str, an(invisexplain));
        }
    }

    /* Now check for graphics symbols */
    alt_i = (sym == (looked ? showsyms[0] : defsyms[0].sym)) ? 0 : (2 + 1);
    for (hit_trap = FALSE, i = 0; i < MAXPCHARS; i++) {
        /* when sym is the default background character, we process
           i == 0 three times: unexplored, stone, dark part of a room */
        if (alt_i < 2) {
            x_str = !alt_i++ ? "unexplored" : submerged ? "unknown" : "stone";
            i = 0; /* for second iteration, undo loop increment */
            /* alt_i is now 1 or 2 */
        } else {
            if (alt_i++ == 2)
                i = 0; /* undo loop increment */
            x_str = defsyms[i].explanation;
            if (submerged && !strcmp(x_str, defsyms[0].explanation))
                x_str = "land"; /* replace "dark part of a room" */
            /* alt_i is now 3 or more and no longer of interest */
        }
        if (sym == (looked ? showsyms[i] : defsyms[i].sym) && *x_str) {
            /* avoid "an unexplored", "an stone", "an air", "a water",
               "a floor of a room", "a dark part of a room";
               article==2 => "the", 1 => "an", 0 => (none) */
            int article = strstri(x_str, " of a room") ? 2
                          : !(alt_i <= 2
                              || strcmp(x_str, "air") == 0
                              || strcmp(x_str, "land") == 0
                              || strcmp(x_str, "water") == 0);

            if (!found) {
                if (is_cmap_trap(i)) {
                    Sprintf(out_str, "%sa trap", prefix);
                    hit_trap = TRUE;
                } else {
                    Sprintf(out_str, "%s%s", prefix,
                            article == 2 ? the(x_str)
                            : article == 1 ? an(x_str) : x_str);
                }
                *firstmatch = x_str;
                found++;
            } else if (!(hit_trap && is_cmap_trap(i))
                       && !(found >= 3 && is_cmap_drawbridge(i))
                       /* don't mention vibrating square outside of Gehennom
                          unless this happens to be one (hallucination?) */
                       && (i != S_vibrating_square || Inhell
                           || (looked && glyph_is_trap(glyph)
                               && glyph_to_trap(glyph) == VIBRATING_SQUARE))) {
                found += append_str(out_str, (article == 2) ? the(x_str)
                                             : (article == 1) ? an(x_str)
                                               : x_str);
                if (is_cmap_trap(i))
                    hit_trap = TRUE;
            }

            if (i == S_altar || is_cmap_trap(i))
                need_to_look = TRUE;
        }
    }

    /* Now check for warning symbols */
    for (i = 1; i < WARNCOUNT; i++) {
        x_str = def_warnsyms[i].explanation;
        if (sym == (looked ? warnsyms[i] : def_warnsyms[i].sym)) {
            if (!found) {
                Sprintf(out_str, "%s%s", prefix, def_warnsyms[i].explanation);
                *firstmatch = def_warnsyms[i].explanation;
                found++;
            } else {
                found += append_str(out_str, def_warnsyms[i].explanation);
            }
            /* Kludge: warning trumps boulders on the display.
               Reveal the boulder too or player can get confused */
            if (looked && sobj_at(BOULDER, cc.x, cc.y))
                Strcat(out_str, " co-located with a boulder");
            break; /* out of for loop*/
        }
    }

    /* if we ignored venom and list turned out to be short, put it back */
    if (skipped_venom && found < 2) {
        x_str = def_oc_syms[VENOM_CLASS].explain;
        if (!found) {
            Sprintf(out_str, "%s%s", prefix, an(x_str));
            *firstmatch = x_str;
            found++;
        } else {
            found += append_str(out_str, an(x_str));
        }
    }

    /* handle optional boulder symbol as a special case */
    if (iflags.bouldersym && sym == iflags.bouldersym) {
        if (!found) {
            *firstmatch = "boulder";
            Sprintf(out_str, "%s%s", prefix, an(*firstmatch));
            found++;
        } else {
            found += append_str(out_str, "boulder");
        }
    }

    /*
     * If we are looking at the screen, follow multiple possibilities or
     * an ambiguous explanation by something more detailed.
     */

    if (found > 4)
        Sprintf(out_str, "%s", "That can be many things");

 didlook:
    if (looked) {
        if (found > 1 || need_to_look) {
            char monbuf[BUFSZ];
            char temp_buf[BUFSZ];

            (void) lookat(cc.x, cc.y, look_buf, monbuf);
            *firstmatch = look_buf;
            if (*(*firstmatch)) {
                Sprintf(temp_buf, " (%s)", *firstmatch);
                (void) strncat(out_str, temp_buf,
                               BUFSZ - strlen(out_str) - 1);
                found = 1; /* we have something to look up */
            }
            if (monbuf[0]) {
                Sprintf(temp_buf, " [seen: %s]", monbuf);
                (void) strncat(out_str, temp_buf,
                               BUFSZ - strlen(out_str) - 1);
            }
        }
    }

    return found;
}

/* also used by getpos hack in do_name.c */
const char what_is_an_unknown_object[] = "an unknown object";

int
do_look(mode, click_cc)
int mode;
coord *click_cc;
{
    boolean quick = (mode == 1); /* use cursor; don't search for "more info" */
    boolean clicklook = (mode == 2); /* right mouse-click method */
    char out_str[BUFSZ];
    const char *firstmatch = 0;
    struct permonst *pm = 0;
    int i = '\0', ans = 0;
    int sym;              /* typed symbol or converted glyph */
    int found;            /* count of matching syms found */
    coord cc;             /* screen pos of unknown glyph */
    boolean save_verbose; /* saved value of flags.verbose */
    boolean from_screen;  /* question from the screen */

    if (!clicklook) {
        if (quick) {
            from_screen = TRUE; /* yes, we want to use the cursor */
            i = 'y';
        } else {
            menu_item *pick_list = (menu_item *) 0;
            winid win;
            anything any;

            any = zeroany;
            win = create_nhwindow(NHW_MENU);
            start_menu(win);
            any.a_char = '/';
            /* 'y' and 'n' to keep backwards compatibility with previous
               versions: "Specify unknown object by cursor?" */
            add_menu(win, NO_GLYPH, &any,
                     flags.lootabc ? 0 : any.a_char, 'y', ATR_NONE,
                     "something on the map", MENU_UNSELECTED);
            any.a_char = 'i';
            add_menu(win, NO_GLYPH, &any,
                     flags.lootabc ? 0 : any.a_char, 0, ATR_NONE,
                     "something you're carrying", MENU_UNSELECTED);
            any.a_char = '?';
            add_menu(win, NO_GLYPH, &any,
                     flags.lootabc ? 0 : any.a_char, 'n', ATR_NONE,
                     "something else (by symbol or name)", MENU_UNSELECTED);
            if (!u.uswallow && !Hallucination) {
                any = zeroany;
                add_menu(win, NO_GLYPH, &any, 0, 0, ATR_NONE,
                         "", MENU_UNSELECTED);
                /* these options work sensibly for the swallowed case,
                   but there's no reason for the player to use them then;
                   objects work fine when hallucinating, but screen
                   symbol/monster class letter doesn't match up with
                   bogus monster type, so suppress when hallucinating */
                any.a_char = 'm';
                add_menu(win, NO_GLYPH, &any,
                         flags.lootabc ? 0 : any.a_char, 0, ATR_NONE,
                         "nearby monsters", MENU_UNSELECTED);
                any.a_char = 'M';
                add_menu(win, NO_GLYPH, &any,
                         flags.lootabc ? 0 : any.a_char, 0, ATR_NONE,
                         "all monsters shown on map", MENU_UNSELECTED);
                any.a_char = 'o';
                add_menu(win, NO_GLYPH, &any,
                         flags.lootabc ? 0 : any.a_char, 0, ATR_NONE,
                         "nearby objects", MENU_UNSELECTED);
                any.a_char = 'O';
                add_menu(win, NO_GLYPH, &any,
                         flags.lootabc ? 0 : any.a_char, 0, ATR_NONE,
                         "all objects shown on map", MENU_UNSELECTED);
            }
            end_menu(win, "What do you want to look at:");
            if (select_menu(win, PICK_ONE, &pick_list) > 0) {
                i = pick_list->item.a_char;
                free((genericptr_t) pick_list);
            }
            destroy_nhwindow(win);
        }

        switch (i) {
        default:
        case 'q':
            return 0;
        case 'y':
        case '/':
            from_screen = TRUE;
            sym = 0;
            cc.x = u.ux;
            cc.y = u.uy;
            break;
        case 'i':
          {
            char invlet;
            struct obj *invobj;

            invlet = display_inventory((const char *) 0, TRUE);
            if (!invlet || invlet == '\033')
                return 0;
            *out_str = '\0';
            for (invobj = invent; invobj; invobj = invobj->nobj)
                if (invobj->invlet == invlet) {
                    strcpy(out_str, singular(invobj, xname));
                    break;
                }
            if (*out_str)
                checkfile(out_str, pm, TRUE, TRUE);
            return 0;
          }
        case '?':
            from_screen = FALSE;
            getlin("Specify what? (type the word)", out_str);
            if (strcmp(out_str, " ")) /* keep single space as-is */
                /* remove leading and trailing whitespace and
                   condense consecutive internal whitespace */
                mungspaces(out_str);
            if (out_str[0] == '\0' || out_str[0] == '\033')
                return 0;

            if (out_str[1]) { /* user typed in a complete string */
                checkfile(out_str, pm, TRUE, TRUE);
                return 0;
            }
            sym = out_str[0];
            break;
        case 'm':
            look_all(TRUE, TRUE); /* list nearby monsters */
            return 0;
        case 'M':
            look_all(FALSE, TRUE); /* list all monsters */
            return 0;
        case 'o':
            look_all(TRUE, FALSE); /* list nearby objects */
            return 0;
        case 'O':
            look_all(FALSE, FALSE); /* list all objects */
            return 0;
        }
    } else { /* clicklook */
        cc.x = click_cc->x;
        cc.y = click_cc->y;
        sym = 0;
        from_screen = FALSE;
    }

    /* Save the verbose flag, we change it later. */
    save_verbose = flags.verbose;
    flags.verbose = flags.verbose && !quick;
    /*
     * The user typed one letter, or we're identifying from the screen.
     */
    do {
        /* Reset some variables. */
        pm = (struct permonst *) 0;
        found = 0;
        out_str[0] = '\0';

        if (from_screen || clicklook) {
            if (from_screen) {
                if (flags.verbose)
                    pline("Please move the cursor to %s.",
                          what_is_an_unknown_object);
                else
                    pline("Pick an object.");

                ans = getpos(&cc, quick, what_is_an_unknown_object);
                if (ans < 0 || cc.x < 0) {
                    flags.verbose = save_verbose;
                    return 0; /* done */
                }
                flags.verbose = FALSE; /* only print long question once */
            }
        }

        found = do_screen_description(cc, (from_screen || clicklook), sym,
                                      out_str, &firstmatch);

        /* Finally, print out our explanation. */
        if (found) {
            /* Used putmixed() because there may be an encoded glyph present
             */
            putmixed(WIN_MESSAGE, 0, out_str);

            /* check the data file for information about this thing */
            if (found == 1 && ans != LOOK_QUICK && ans != LOOK_ONCE
                && (ans == LOOK_VERBOSE || (flags.help && !quick))
                && !clicklook) {
                char temp_buf[BUFSZ];

                Strcpy(temp_buf, firstmatch);
                checkfile(temp_buf, pm, FALSE,
                          (boolean) (ans == LOOK_VERBOSE));
            }
        } else {
            pline("I've never heard of such things.");
        }

    } while (from_screen && !quick && ans != LOOK_ONCE && !clicklook);

    flags.verbose = save_verbose;
    return 0;
}

STATIC_OVL void
look_all(nearby, do_mons)
boolean nearby; /* True => within BOLTLIM, False => entire map */
boolean do_mons; /* True => monsters, False => objects */
{
    winid win;
    int x, y, lo_x, lo_y, hi_x, hi_y, glyph, count = 0;
    char lookbuf[BUFSZ], outbuf[BUFSZ];

    win = create_nhwindow(NHW_TEXT);
    lo_y = nearby ? max(u.uy - BOLT_LIM, 0) : 0;
    lo_x = nearby ? max(u.ux - BOLT_LIM, 1) : 1;
    hi_y = nearby ? min(u.uy + BOLT_LIM, ROWNO - 1) : ROWNO - 1;
    hi_x = nearby ? min(u.ux + BOLT_LIM, COLNO - 1) : COLNO - 1;
    for (y = lo_y; y <= hi_y; y++) {
        for (x = lo_x; x <= hi_x; x++) {
            lookbuf[0] = '\0';
            glyph = glyph_at(x, y);
            if (do_mons) {
                if (glyph_is_monster(glyph)) {
                    struct monst *mtmp;

                    bhitpos.x = x; /* [is this actually necessary?] */
                    bhitpos.y = y;
                    if (x == u.ux && y == u.uy && canspotself()) {
                        (void) self_lookat(lookbuf);
                        ++count;
                    } else if ((mtmp = m_at(x, y)) != 0) {
                        look_at_monster(lookbuf, (char *) 0, mtmp, x, y);
                        ++count;
                    }
                } else if (glyph_is_invisible(glyph)) {
                    /* remembered, unseen, creature */
                    Strcpy(lookbuf, invisexplain);
                    ++count;
                } else if (glyph_is_warning(glyph)) {
                    int warnindx = glyph_to_warning(glyph);

                    Strcpy(lookbuf, def_warnsyms[warnindx].explanation);
                    ++count;
                }
            } else { /* !do_mons */
                if (glyph_is_object(glyph)) {
                    look_at_object(lookbuf, x, y, glyph);
                    ++count;
                }
            }
            if (*lookbuf) {
                char coordbuf[20], which[12], cmode;

                cmode = (iflags.getpos_coords != GPCOORDS_NONE)
                           ? iflags.getpos_coords : GPCOORDS_MAP;
                if (count == 1) {
                    Strcpy(which, do_mons ? "monsters" : "objects");
                    if (nearby)
                        Sprintf(outbuf, "%s currently shown near %s:",
                                upstart(which),
                                (cmode != GPCOORDS_COMPASS)
                                  ? coord_desc(u.ux, u.uy, coordbuf, cmode)
                                  : !canspotself() ? "your position" : "you");
                    else
                        Sprintf(outbuf, "All %s currently shown on the map:",
                                which);
                    putstr(win, 0, outbuf);
                    putstr(win, 0, "");
                }
                /* prefix: "coords  C  " where 'C' is mon or obj symbol */
                Sprintf(outbuf, (cmode == GPCOORDS_SCREEN) ? "%s  "
                                  : (cmode == GPCOORDS_MAP) ? "%8s  "
                                      : "%12s  ",
                        coord_desc(x, y, coordbuf, cmode));
                Sprintf(eos(outbuf), "%s  ", encglyph(glyph));
                /* guard against potential overflow */
                lookbuf[sizeof lookbuf - 1 - strlen(outbuf)] = '\0';
                Strcat(outbuf, lookbuf);
                putmixed(win, 0, outbuf);
            }
        }
    }
    if (count)
        display_nhwindow(win, TRUE);
    else
        pline("No %s are currently shown %s.",
              do_mons ? "monsters" : "objects",
              nearby ? "nearby" : "on the map");
    destroy_nhwindow(win);
}

/* the '/' command */
int
dowhatis()
{
    return do_look(0, (coord *) 0);
}

/* the ';' command */
int
doquickwhatis()
{
    return do_look(1, (coord *) 0);
}

/* the '^' command */
int
doidtrap()
{
    register struct trap *trap;
    int x, y, tt, glyph;

    if (!getdir("^"))
        return 0;
    x = u.ux + u.dx;
    y = u.uy + u.dy;

    /* check fake bear trap from confused gold detection */
    glyph = glyph_at(x, y);
    if (glyph_is_trap(glyph) && (tt = glyph_to_trap(glyph)) == BEAR_TRAP) {
        boolean chesttrap = trapped_chest_at(tt, x, y);

        if (chesttrap || trapped_door_at(tt, x, y)) {
            pline("That is a trapped %s.", chesttrap ? "chest" : "door");
            return 0; /* trap ID'd, but no time elapses */
        }
    }

    for (trap = ftrap; trap; trap = trap->ntrap)
        if (trap->tx == x && trap->ty == y) {
            if (!trap->tseen)
                break;
            tt = trap->ttyp;
            if (u.dz) {
                if (u.dz < 0 ? (tt == TRAPDOOR || tt == HOLE)
                             : tt == ROCKTRAP)
                    break;
            }
            tt = what_trap(tt);
            pline("That is %s%s%s.",
                  an(defsyms[trap_to_defsym(tt)].explanation),
                  !trap->madeby_u
                     ? ""
                     : (tt == WEB)
                        ? " woven"
                        /* trap doors & spiked pits can't be made by
                           player, and should be considered at least
                           as much "set" as "dug" anyway */
                        : (tt == HOLE || tt == PIT)
                           ? " dug"
                           : " set",
                  !trap->madeby_u ? "" : " by you");
            return 0;
        }
    pline("I can't see a trap there.");
    return 0;
}

/*
    Implements a rudimentary if/elif/else/endif interpretor and use
    conditionals in dat/cmdhelp to describe what command each keystroke
    currently invokes, so that there isn't a lot of "(debug mode only)"
    and "(if number_pad is off)" cluttering the feedback that the user
    sees.  (The conditionals add quite a bit of clutter to the raw data
    but users don't see that.  number_pad produces a lot of conditional
    commands:  basic letters vs digits, 'g' vs 'G' for '5', phone
    keypad vs normal layout of digits, and QWERTZ keyboard swap between
    y/Y/^Y/M-y/M-Y/M-^Y and z/Z/^Z/M-z/M-Z/M-^Z.)
    
    The interpretor understands
     '&#' for comment,
     '&? option' for 'if' (also '&? !option'
                           or '&? option=value[,value2,...]'
                           or '&? !option=value[,value2,...]'),
     '&: option' for 'elif' (with argument variations same as 'if';
                             any number of instances for each 'if'),
     '&:' for 'else' (also '&: #comment';
                      0 or 1 instance for a given 'if'), and
     '&.' for 'endif' (also '&. #comment'; required for each 'if').
    
    The option handling is a bit of a mess, with no generality for
    which options to deal with and only a comma separated list of
    integer values for the '=value' part.  number_pad is the only
    supported option that has a value; the few others (wizard/debug,
    rest_on_space, #if SHELL, #if SUSPEND) are booleans.
*/

STATIC_DCL void
whatdoes_help()
{
    dlb *fp;
    char *p, buf[BUFSZ];
    winid tmpwin = create_nhwindow(NHW_TEXT);

    fp = dlb_fopen(KEYHELP, "r");
    if (!fp) {
        pline("Cannot open \"%s\" data file!", KEYHELP);
        display_nhwindow(WIN_MESSAGE, TRUE);
        return;
    }
    while (dlb_fgets(buf, (int) sizeof buf, fp)) {
        if (*buf == '#')
            continue;
        for (p = buf; *p; p++)
            if (*p != ' ' && *p != '\t')
                break;
        putstr(tmpwin, 0, p);
    }
    (void) dlb_fclose(fp);
    display_nhwindow(tmpwin, TRUE);
    destroy_nhwindow(tmpwin);
}

#define WD_STACKLIMIT 5
struct wd_stack_frame {
    Bitfield(active, 1);
    Bitfield(been_true, 1);
    Bitfield(else_seen, 1);
};

STATIC_DCL boolean FDECL(whatdoes_cond, (char *, struct wd_stack_frame *,
                                         int *, int));

STATIC_OVL boolean
whatdoes_cond(buf, stack, depth, lnum)
char *buf;
struct wd_stack_frame *stack;
int *depth, lnum;
{
    const char badstackfmt[] = "cmdhlp: too many &%c directives at line %d.";
    boolean newcond, neg, gotopt;
    char *p, *q, act = buf[1];
    int np = 0;

    newcond = (act == '?' || !stack[*depth].been_true);
    buf += 2;
    mungspaces(buf);
    if (act == '#' || *buf == '#' || !*buf || !newcond) {
        gotopt = (*buf && *buf != '#');
        *buf = '\0';
        neg = FALSE; /* lint suppression */
        p = q = (char *) 0;
    } else {
        gotopt = TRUE;
        if ((neg = (*buf == '!')) != 0)
            if (*++buf == ' ')
                ++buf;
        p = index(buf, '='), q = index(buf, ':');
        if (!p || (q && q < p))
            p = q;
        if (p) { /* we have a value specified */
            /* handle a space before or after (or both) '=' (or ':') */
            if (p > buf && p[-1] == ' ')
                p[-1] = '\0'; /* end of keyword in buf[] */
            *p++ = '\0'; /* terminate keyword, advance to start of value */
            if (*p == ' ')
                p++;
        }
    }
    if (*buf && (act == '?' || act == ':')) {
        if (!strcmpi(buf, "number_pad")) {
            if (!p) {
                newcond = iflags.num_pad;
            } else {
                /* convert internal encoding (separate yes/no and 0..3)
                   back to user-visible one (-1..4) */
                np = iflags.num_pad ? (1 + iflags.num_pad_mode) /* 1..4 */
                                    : (-1 * iflags.num_pad_mode); /* -1..0 */
                newcond = FALSE;
                for (; p; p = q) {
                    q = index(p, ',');
                    if (q)
                        *q++ = '\0';
                    if (atoi(p) == np) {
                        newcond = TRUE;
                        break;
                    }
                }
            }
        } else if (!strcmpi(buf, "rest_on_space")) {
            newcond = flags.rest_on_space;
        } else if (!strcmpi(buf, "debug") || !strcmpi(buf, "wizard")) {
            newcond = flags.debug; /* == wizard */
        } else if (!strcmpi(buf, "shell")) {
#ifdef SHELL
            /* should we also check sysopt.shellers? */
            newcond = TRUE;
#else
            newcond = FALSE;
#endif
        } else if (!strcmpi(buf, "suspend")) {
#ifdef SUSPEND
            /* sysopt.shellers is also used for dosuspend()... */
            newcond = TRUE;
#else
            newcond = FALSE;
#endif
        } else {
            impossible(
                "cmdhelp: unrecognized &%c conditional at line %d: \"%.20s\"",
                       act, lnum, buf);
            neg = FALSE;
        }
        /* this works for number_pad too: &? !number_pad:-1,0
           would be true for 1..4 after negation */
        if (neg)
            newcond = !newcond;
    }
    switch (act) {
    default:
    case '#': /* comment */
        break;
    case '.': /* endif */
        if (--*depth < 0) {
            impossible(badstackfmt, '.', lnum);
            *depth = 0;
        }
        break;
    case ':': /* else or elif */
        if (*depth == 0 || stack[*depth].else_seen) {
            impossible(badstackfmt, ':', lnum);
            *depth = 1; /* so that stack[*depth - 1] is a valid access */
        }
        if (stack[*depth].active || stack[*depth].been_true
            || !stack[*depth - 1].active)
            stack[*depth].active = 0;
        else if (newcond)
            stack[*depth].active = stack[*depth].been_true = 1;
        if (!gotopt)
            stack[*depth].else_seen = 1;
        break;
    case '?': /* if */
        if (++*depth >= WD_STACKLIMIT) {
            impossible(badstackfmt, '?', lnum);
            *depth = WD_STACKLIMIT - 1;
        }
        stack[*depth].active = (newcond && stack[*depth - 1].active) ? 1 : 0;
        stack[*depth].been_true = stack[*depth].active;
        stack[*depth].else_seen = 0;
        break;
    }
    return stack[*depth].active ? TRUE : FALSE;
}

char *
dowhatdoes_core(q, cbuf)
char q;
char *cbuf;
{
    dlb *fp;
    char buf[BUFSZ];
    struct wd_stack_frame stack[WD_STACKLIMIT];
    boolean cond;
    int ctrl, meta, depth = 0, lnum = 0;

    fp = dlb_fopen(CMDHELPFILE, "r");
    if (!fp) {
        pline("Cannot open \"%s\" data file!", CMDHELPFILE);
        return 0;
    }

    meta = (0x80 & (uchar) q) != 0;
    if (meta)
        q &= 0x7f;
    ctrl = (0x1f & (uchar) q) == (uchar) q;
    if (ctrl)
        q |= 0x40; /* NUL -> '@', ^A -> 'A', ... ^Z -> 'Z', ^[ -> '[', ... */
    else if (q == 0x7f)
        ctrl = 1, q = '?';

    (void) memset((genericptr_t) stack, 0, sizeof stack);
    cond = stack[0].active = 1;
    while (dlb_fgets(buf, sizeof buf, fp)) {
        ++lnum;
        if (buf[0] == '&' && buf[1] && index("?:.#", buf[1])) {
            cond = whatdoes_cond(buf, stack, &depth, lnum);
            continue;
        }
        if (!cond)
            continue;
        if (meta ? (buf[0] == 'M' && buf[1] == '-'
                    && (ctrl ? buf[2] == '^' && highc(buf[3]) == q
                             : buf[2] == q))
                 : (ctrl ? buf[0] == '^' && highc(buf[1]) == q
                         : buf[0] == q)) {
            (void) strip_newline(buf);
            if (index(buf, '\t'))
                (void) tabexpand(buf);
            if (meta && ctrl && buf[4] == ' ') {
                (void) strncpy(buf, "M-^?    ", 8);
                buf[3] = q;
            } else if (meta && buf[3] == ' ') {
                (void) strncpy(buf, "M-?     ", 8);
                buf[2] = q;
            } else if (ctrl && buf[2] == ' ') {
                (void) strncpy(buf, "^?      ", 8);
                buf[1] = q;
            } else if (buf[1] == ' ') {
                (void) strncpy(buf, "?       ", 8);
                buf[0] = q;
            }
            (void) dlb_fclose(fp);
            Strcpy(cbuf, buf);
            return cbuf;
        }
    }
    (void) dlb_fclose(fp);
    if (depth != 0)
        impossible("cmdhelp: mismatched &? &: &. conditionals.");
    return (char *) 0;
}

int
dowhatdoes()
{
    static boolean once = FALSE;
    char bufr[BUFSZ];
    char q, *reslt;

    if (!once) {
        pline("Ask about '&' or '?' to get more info.%s",
#ifdef ALTMETA
              iflags.altmeta ? "  (For ESC, type it twice.)" :
#endif
              "");
        once = TRUE;
    }
#if defined(UNIX) || defined(VMS)
    introff(); /* disables ^C but not ^\ */
#endif
    q = yn_function("What command?", (char *) 0, '\0');
#ifdef ALTMETA
    if (q == '\033' && iflags.altmeta) {
        /* in an ideal world, we would know whether another keystroke
           was already pending, but this is not an ideal world...
           if user typed ESC, we'll essentially hang until another
           character is typed */
        q = yn_function("]", (char *) 0, '\0');
        if (q != '\033')
            q = (char) ((uchar) q | 0200);
    }
#endif /*ALTMETA*/
#if defined(UNIX) || defined(VMS)
    intron(); /* reenables ^C */
#endif
    reslt = dowhatdoes_core(q, bufr);
    if (reslt) {
        if (q == '&' || q == '?')
            whatdoes_help();
        pline("%s", reslt);
    } else {
        pline("No such command '%s', char code %d (0%03o or 0x%02x).",
              visctrl(q), (uchar) q, (uchar) q, (uchar) q);
    }
    return 0;
}

STATIC_OVL void
docontact()
{
    winid cwin = create_nhwindow(NHW_TEXT);
    char buf[BUFSZ];

    if (sysopt.support) {
        /*XXX overflow possibilities*/
        Sprintf(buf, "To contact local support, %s", sysopt.support);
        putstr(cwin, 0, buf);
        putstr(cwin, 0, "");
    } else if (sysopt.fmtd_wizard_list) { /* formatted SYSCF WIZARDS */
        Sprintf(buf, "To contact local support, contact %s.",
                sysopt.fmtd_wizard_list);
        putstr(cwin, 0, buf);
        putstr(cwin, 0, "");
    }
    putstr(cwin, 0, "To contact the NetHack development team directly,");
    /*XXX overflow possibilities*/
    Sprintf(buf, "see the 'Contact' form on our website or email <%s>.",
            DEVTEAM_EMAIL);
    putstr(cwin, 0, buf);
    putstr(cwin, 0, "");
    putstr(cwin, 0, "For more information on NetHack, or to report a bug,");
    Sprintf(buf, "visit our website \"%s\".", DEVTEAM_URL);
    putstr(cwin, 0, buf);
    display_nhwindow(cwin, FALSE);
    destroy_nhwindow(cwin);
}

void
dispfile_help()
{
    display_file(HELP, TRUE);
}

void
dispfile_shelp()
{
    display_file(SHELP, TRUE);
}

void
dispfile_optionfile()
{
    display_file(OPTIONFILE, TRUE);
}

void
dispfile_license()
{
    display_file(LICENSE, TRUE);
}

void
dispfile_debughelp()
{
    display_file(DEBUGHELP, TRUE);
}

void
hmenu_doextversion()
{
    (void) doextversion();
}

void
hmenu_dohistory()
{
    (void) dohistory();
}

void
hmenu_dowhatis()
{
    (void) dowhatis();
}

void
hmenu_dowhatdoes()
{
    (void) dowhatdoes();
}

void
hmenu_doextlist()
{
    (void) doextlist();
}

/* data for dohelp() */
static struct {
    void (*f)();
    const char *text;
} help_menu_items[] = {
    { hmenu_doextversion, "About NetHack (version information)." },
    { dispfile_help, "Long description of the game and commands." },
    { dispfile_shelp, "List of game commands." },
    { hmenu_dohistory, "Concise history of NetHack." },
    { hmenu_dowhatis, "Info on a character in the game display." },
    { hmenu_dowhatdoes, "Info on what a given key does." },
    { option_help, "List of game options." },
    { dispfile_optionfile, "Longer explanation of game options." },
    { hmenu_doextlist, "List of extended commands." },
    { dispfile_license, "The NetHack license." },
    { docontact, "Support information." },
#ifdef PORT_HELP
    { port_help, "%s-specific help and commands." },
#endif
    { dispfile_debughelp, "List of wizard-mode commands." },
    { NULL, (char *) 0 }
};

/* the '?' command */
int
dohelp()
{
    winid tmpwin = create_nhwindow(NHW_MENU);
    char helpbuf[QBUFSZ];
    int i, n;
    menu_item *selected;
    anything any;
    int sel;
    char *bufptr;

    any = zeroany; /* zero all bits */
    start_menu(tmpwin);

    for (i = 0; help_menu_items[i].text; i++) {
        if (!wizard && help_menu_items[i].f == dispfile_debughelp)
            continue;
        if (help_menu_items[i].text[0] == '%') {
            Sprintf(helpbuf, help_menu_items[i].text, PORT_ID);
            bufptr = helpbuf;
        } else {
            bufptr = (char *)help_menu_items[i].text;
        }
        any.a_int = i + 1;
        add_menu(tmpwin, NO_GLYPH, &any, 0, 0, ATR_NONE,
                 bufptr, MENU_UNSELECTED);
    }
    end_menu(tmpwin, "Select one item:");
    n = select_menu(tmpwin, PICK_ONE, &selected);
    destroy_nhwindow(tmpwin);
    if (n > 0) {
        sel = selected[0].item.a_int - 1;
        free((genericptr_t) selected);
        (void)(*help_menu_items[sel].f)();
    }
    return 0;
}

/* the 'V' command; also a choice for '?' */
int
dohistory()
{
    display_file(HISTORY, TRUE);
    return 0;
}

/*pager.c*/