1: /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1984. */
   2: static char rcsid[] = "$Header: move.c,v 2.4 85/08/22 16:05:16 timo Exp $";
   3: 
   4: /*
   5:  * B editor -- Process arrow keys in four directions, plus TAB.
   6:  */
   7: 
   8: #include "b.h"
   9: #include "bobj.h"
  10: #include "node.h"
  11: #include "supr.h"
  12: #include "gram.h"
  13: 
  14: #define Left (-1)
  15: #define Rite 1
  16: 
  17: 
  18: /*
  19:  * Common code for PREVIOUS and NEXT commands.
  20:  */
  21: 
  22: Hidden bool
  23: prevnext(ep, direction)
  24:     environ *ep;
  25: {
  26:     node n;
  27:     node n1;
  28:     int nch;
  29:     int i;
  30:     int len;
  31:     int sym;
  32:     string *rp;
  33: 
  34:     higher(ep);
  35:     switch (ep->mode) {
  36:     case VHOLE:
  37:     case FHOLE:
  38:     case ATBEGIN:
  39:     case ATEND:
  40:         if (direction == Left)
  41:             leftvhole(ep);
  42:         else
  43:             ritevhole(ep);
  44:     }
  45: 
  46:     for (;;) {
  47:         n = tree(ep->focus);
  48:         nch = nchildren(n);
  49:         rp = noderepr(n);
  50: 
  51:         switch (ep->mode) {
  52: 
  53:         case ATBEGIN:
  54:         case ATEND:
  55:             ep->mode = WHOLE;
  56:             continue;
  57: 
  58:         case VHOLE:
  59:         case FHOLE:
  60:             if (direction == Rite) {
  61:                 if (ep->s1&1)
  62:                     len = Fwidth(rp[ep->s1/2]);
  63:                 else {
  64:                     n1 = child(n, ep->s1/2);
  65:                     len = width(n1);
  66:                 }
  67:             }
  68:             if (direction == Rite ? ep->s2 >= len : ep->s2 <= 0) {
  69:                 ep->mode = SUBSET;
  70:                 ep->s2 = ep->s1;
  71:                 return nextchar(ep, direction);
  72:             }
  73:             ep->s2 += direction;
  74:             return Yes;
  75: 
  76:         case SUBRANGE:
  77:             if (direction == Rite) {
  78:                 if (ep->s1&1)
  79:                     len = Fwidth(rp[ep->s1/2]);
  80:                 else {
  81:                     n1 = child(n, ep->s1/2);
  82:                     len = width(n1);
  83:                 }
  84:             }
  85:             if (direction == Left ? ep->s2 <= 0 : ep->s3 >= len-1) {
  86:                 ep->mode = SUBSET;
  87:                 ep->s2 = ep->s1;
  88:                 return nextchar(ep, direction);
  89:             }
  90:             if (direction == Rite)
  91:                 ep->s2 = ++ep->s3;
  92:             else
  93:                 ep->s3 = --ep->s2;
  94:             return Yes;
  95: 
  96:         case SUBSET:
  97:             if (direction == Rite ? ep->s2 > 2*nch : ep->s1 <= 1) {
  98:                 ep->mode = WHOLE;
  99:                 continue;
 100:             }
 101:             if (direction == Rite)
 102:                 ep->s1 = ++ep->s2;
 103:             else
 104:                 ep->s2 = --ep->s1;
 105:             if (ep->s1&1) {
 106:                 if (!Fw_positive(rp[ep->s1/2]) || allspaces(rp[ep->s1/2]))
 107:                     continue;
 108:             }
 109:             else {
 110:                 sym = symbol(n);
 111:                 if (downi(&ep->focus, ep->s1/2)) {
 112:                     n = tree(ep->focus);
 113:                     if (((value)n)->type == Tex)
 114:                         s_up(ep);
 115:                     else {
 116:                         if (ep->s1 == 2*nch && direction == Rite
 117:                             && issublist(sym) && samelevel(sym, symbol(n))) {
 118:                             ep->mode = SUBLIST;
 119:                             ep->s3 = 1;
 120:                             return Yes;
 121:                         }
 122:                         ep->mode = WHOLE;
 123:                         if (width(n) == 0)
 124:                             continue;
 125:                     }
 126:                 }
 127:             }
 128:             return Yes;
 129: 
 130:         case SUBLIST:
 131:             sym = symbol(n);
 132:             if (direction == Left) {
 133:                 i = ichild(ep->focus);
 134:                 if (!up(&ep->focus))
 135:                     return No;
 136:                 higher(ep);
 137:                 n = tree(ep->focus);
 138:                 if (i == nchildren(n) && samelevel(sym, symbol(n))) {
 139:                     ep->s3 = 1;
 140:                     return Yes;
 141:                 }
 142:                 ep->mode = SUBSET;
 143:                 ep->s1 = ep->s2 = 2*i;
 144:                 continue;
 145:             }
 146:             for (i = ep->s3; i > 0; --i)
 147:                 if (!downrite(&ep->focus))
 148:                     return No; /* Sorry... */
 149:             if (samelevel(sym, symbol(tree(ep->focus))))
 150:                 ep->s3 = 1;
 151:             else
 152:                 ep->mode = WHOLE;
 153:             return Yes;
 154: 
 155:         case WHOLE:
 156:             i = ichild(ep->focus);
 157:             if (!up(&ep->focus))
 158:                 return No;
 159:             higher(ep);
 160:             ep->mode = SUBSET;
 161:             ep->s1 = ep->s2 = 2*i;
 162:             continue;
 163: 
 164:         default:
 165:             Abort();
 166:         }
 167:     }
 168:     /* Not reached */
 169: }
 170: 
 171: Visible bool leftarrow(ep)
 172:     environ *ep;
 173: {
 174:     int w;
 175:     bool hole;
 176: 
 177:     if (narrow(ep)) {
 178:         while (narrow(ep))
 179:             ;
 180:         return Yes;
 181:     }
 182:     hole= ep->mode == WHOLE; /* Can't narrow and still WHOLE: */
 183:                  /* a real hole which needs some hacking. */
 184:     if (!previous(ep))
 185:         return No;
 186:     if (hole) {
 187:         for (;;) {
 188:             w= focwidth(ep);
 189:             if (w >= 0 && w <= 1)
 190:                 break;
 191:             if (!rnarrow(ep))
 192:                 return No;
 193:         }
 194:         narrow(ep);
 195:     }
 196:     else {
 197:         while (rnarrow(ep))
 198:             ;
 199:     }
 200:     return Yes;
 201: }
 202: 
 203: Visible bool ritearrow(ep)
 204:     environ *ep;
 205: {
 206:     while (narrow(ep))
 207:         ;
 208:     if (!next(ep))
 209:         return No;
 210:     while (narrow(ep))
 211:         ;
 212:     return Yes;
 213: }
 214: 
 215: 
 216: Visible bool
 217: previous(ep)
 218:     environ *ep;
 219: {
 220:     if (!prevnext(ep, Left))
 221:         return No;
 222:     return Yes;
 223: }
 224: 
 225: 
 226: Visible bool
 227: next(ep)
 228:     environ *ep;
 229: {
 230:     if (!prevnext(ep, Rite))
 231:         return No;
 232:     return Yes;
 233: }
 234: 
 235: 
 236: /*
 237:  * Position focus at next or previous char relative to current position.
 238:  * Assume current position given as SUBSET.
 239:  */
 240: 
 241: Hidden bool
 242: nextchar(ep, direction)
 243:     register environ *ep;
 244:     register int direction;
 245: {
 246:     register int ich;
 247:     register int nch;
 248:     register node n;
 249:     node n1;
 250:     register int len;
 251:     string *rp;
 252: 
 253:     Assert(ep->mode == SUBSET);
 254:     for (;;) {
 255:         n = tree(ep->focus);
 256:         rp = noderepr(n);
 257:         nch = nchildren(n);
 258:         if (direction == Left)
 259:             ep->s2 = --ep->s1;
 260:         else
 261:             ep->s1 = ++ep->s2;
 262:         if (direction == Left ? ep->s1 < 1 : ep->s2 > 2*nch+1) {
 263:             ich = ichild(ep->focus);
 264:             if (!up(&ep->focus))
 265:                 return No; /* *ep is garbage now! */
 266:             higher(ep);
 267:             ep->s1 = ep->s2 = 2*ich;
 268:             continue;
 269:         }
 270:         if (ep->s1&1) {
 271:             len = Fwidth(rp[ep->s1/2]);
 272:             if (len > 0) {
 273:                 ep->mode = SUBRANGE;
 274:                 ep->s2 = ep->s3 = direction == Left ? len-1 : 0;
 275:                 return Yes;
 276:             }
 277:             continue;
 278:         }
 279:         n1 = child(n, ep->s1/2);
 280:         len = width(n1);
 281:         if (len == 0)
 282:             continue;
 283:         if (!downi(&ep->focus, ep->s1/2))
 284:             return No; /* Sorry... */
 285:         n = tree(ep->focus);
 286:         if (((value)n)->type == Tex) {
 287:             s_up(ep);
 288:             ep->mode = SUBRANGE;
 289:             ep->s2 = ep->s3 = direction == Left ? len-1 : 0;
 290:             return Yes;
 291:         }
 292:         if (direction == Left) {
 293:             nch = nchildren(n);
 294:             ep->s1 = ep->s2 = 2*(nch+1);
 295:         }
 296:         else
 297:             ep->s1 = ep->s2 = 0;
 298:     }
 299:     /* Not reached */
 300: }
 301: 
 302: 
 303: /*
 304:  * Up and down arrows.
 305:  */
 306: 
 307: Hidden bool
 308: updownarrow(ep, yincr)
 309:     environ *ep;
 310:     int yincr;
 311: {
 312:     int y, x;
 313: 
 314:     while (narrow(ep))
 315:         ;
 316:     y= lineno(ep) + yincr;
 317:     x= colno(ep);
 318:     if (!gotoyx(ep, y, x))
 319:         return No;
 320:     gotofix(ep, y, x);
 321:     while (narrow(ep))
 322:         ;
 323:     return Yes;
 324: }
 325: 
 326: Visible bool
 327: uparrow(ep)
 328:     environ *ep;
 329: {
 330:     return updownarrow(ep, -1);
 331: }
 332: 
 333: Visible bool
 334: downarrow(ep)
 335:     environ *ep;
 336: {
 337:     return updownarrow(ep, 1);
 338: }
 339: 
 340: Visible bool
 341: upline(ep)
 342:     register environ *ep;
 343: {
 344:     register int y;
 345: 
 346:     y = lineno(ep);
 347:     if (y <= 0)
 348:         return No;
 349:     if (!gotoyx(ep, y-1, 0))
 350:         return No;
 351:     oneline(ep);
 352:     return Yes;
 353: }
 354: 
 355: Visible bool
 356: downline(ep)
 357:     register environ *ep;
 358: {
 359:     register int w;
 360: 
 361:     if (!parent(ep->focus) && ep->mode == ATEND)
 362:         return No; /* Superfluous? */
 363:     w = -focwidth(ep);
 364:     if (w <= 0)
 365:         w = 1;
 366:     if (!gotoyx(ep, lineno(ep) + w, 0))
 367:         return No;
 368:     oneline(ep);
 369:     return Yes;
 370: }
 371: 
 372: 
 373: /*
 374:  * ACCEPT command
 375:  * move to next Hole hole or to end of suggestion or to end of line.
 376:  */
 377: 
 378: 
 379: Visible bool
 380: accept(ep)
 381:     environ *ep;
 382: {
 383:     int i;
 384:     string repr;
 385: 
 386:     shrink(ep);
 387:     switch (ep->mode) {
 388:     case ATBEGIN:
 389:     case ATEND:
 390:     case FHOLE:
 391:     case VHOLE:
 392:         ritevhole(ep);
 393:     }
 394:     if (symbol(tree(ep->focus)) == Hole)
 395:         ep->mode = ATEND;
 396:     switch (ep->mode) {
 397:     case ATBEGIN:
 398:     case SUBLIST:
 399:     case WHOLE:
 400:         i = 1;
 401:         break;
 402:     case ATEND:
 403:         i = 2*nchildren(tree(ep->focus)) + 2;
 404:         break;
 405:     case SUBRANGE:
 406:     case VHOLE:
 407:     case FHOLE:
 408:         i = ep->s1;
 409:         if (ep->s2 > 0 && i > 2*nchildren(tree(ep->focus)))
 410:             ++i; /* Kludge so after E?LSE: the focus moves to ELSE: ? */
 411:         break;
 412:     case SUBSET:
 413:         i = ep->s1 - 1;
 414:         break;
 415:     default:
 416:         Abort();
 417:     }
 418:     ep->mode = WHOLE;
 419:     for (;;) {
 420:         if (i/2 == nchildren(tree(ep->focus))) {
 421:             repr = noderepr(tree(ep->focus))[i/2];
 422:             if (Fw_positive(repr))
 423:                 break;
 424:         }
 425:         if (tabstop(ep, i + 1))
 426:             return Yes;
 427:         i = 2*ichild(ep->focus) + 1;
 428:         if (!up(&ep->focus))
 429:             break;
 430:         higher(ep);
 431:     }
 432:     ep->mode = ATEND;
 433:     return Yes;
 434: }
 435: 
 436: 
 437: /*
 438:  * Find suitable tab stops for accept.
 439:  */
 440: 
 441: Hidden bool
 442: tabstop(ep, i)
 443:     environ *ep;
 444:     int i;
 445: {
 446:     node n = tree(ep->focus);
 447:     int nch;
 448:     string repr;
 449: 
 450:     if (Type(n) == Tex)
 451:         return No;
 452:     nch = nchildren(n);
 453:     if (i/2 > nch)
 454:         return No;
 455:     if (symbol(n) == Hole) {
 456:         ep->mode = WHOLE;
 457:         return Yes;
 458:     }
 459:     if (i < 2) {
 460:         i = 2;
 461:         if (width(n) < 0) {
 462:             repr = noderepr(n)[0];
 463:             if (Fw_negative(repr)) {
 464:                 ep->mode = ATBEGIN;
 465:                 leftvhole(ep);
 466:                 return Yes;
 467:             }
 468:         }
 469:     }
 470:     for (i /= 2; i <= nch; ++i) {
 471:         s_downi(ep, i);
 472:         if (tabstop(ep, 1))
 473:             return Yes;
 474:         s_up(ep);
 475:     }
 476:     return No;
 477: }

Defined functions

accept defined in line 379; used 1 times
downarrow defined in line 333; used 1 times
downline defined in line 355; used 1 times
leftarrow defined in line 171; used 1 times
next defined in line 226; used 2 times
nextchar defined in line 241; used 2 times
previous defined in line 216; used 2 times
prevnext defined in line 22; used 2 times
ritearrow defined in line 203; used 1 times
tabstop defined in line 441; used 2 times
uparrow defined in line 326; used 1 times
updownarrow defined in line 307; used 2 times
upline defined in line 340; used 1 times

Defined variables

rcsid defined in line 2; never used

Defined macros

Left defined in line 14; used 9 times
Rite defined in line 15; used 8 times
Last modified: 1985-08-27
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