opttbl.c

   1 /*
   2  * Copyright (C) 1984-2022  Mark Nudelman
   3  *
   4  * You may distribute under the terms of either the GNU General Public
   5  * License or the Less License, as specified in the README file.
   6  *
   7  * For more information, see the README file.
   8  */
   9
  10
  11 /*
  12  * The option table.
  13  */
  14
  15 #include "less.h"
  16 #include "option.h"
  17
  18 /*
  19  * Variables controlled by command line options.
  20  */
  21 public int quiet;               /* Should we suppress the audible bell? */
  22 public int how_search;          /* Where should forward searches start? */
  23 public int top_scroll;          /* Repaint screen from top?
  24                                    (alternative is scroll from bottom) */
  25 public int pr_type;             /* Type of prompt (short, medium, long) */
  26 public int bs_mode;             /* How to process backspaces */
  27 public int know_dumb;           /* Don't complain about dumb terminals */
  28 public int quit_at_eof;         /* Quit after hitting end of file twice */
  29 public int quit_if_one_screen;  /* Quit if EOF on first screen */
  30 public int squeeze;             /* Squeeze multiple blank lines into one */
  31 public int tabstop;             /* Tab settings */
  32 public int back_scroll;         /* Repaint screen on backwards movement */
  33 public int forw_scroll;         /* Repaint screen on forward movement */
  34 public int caseless;            /* Do "caseless" searches */
  35 public int linenums;            /* Use line numbers */
  36 public int autobuf;             /* Automatically allocate buffers as needed */
  37 public int bufspace;            /* Max buffer space per file (K) */
  38 public int ctldisp;             /* Send control chars to screen untranslated */
  39 public int force_open;          /* Open the file even if not regular file */
  40 public int swindow;             /* Size of scrolling window */
  41 public int jump_sline;          /* Screen line of "jump target" */
  42 public long jump_sline_fraction = -1;
  43 public long shift_count_fraction = -1;
  44 public int chopline;            /* Truncate displayed lines at screen width */
  45 public int no_init;             /* Disable sending ti/te termcap strings */
  46 public int no_keypad;           /* Disable sending ks/ke termcap strings */
  47 public int twiddle;             /* Show tildes after EOF */
  48 public int show_attn;           /* Hilite first unread line */
  49 public int shift_count;         /* Number of positions to shift horizontally */
  50 public int status_col;          /* Display a status column */
  51 public int use_lessopen;        /* Use the LESSOPEN filter */
  52 public int quit_on_intr;        /* Quit on interrupt */
  53 public int follow_mode;         /* F cmd Follows file desc or file name? */
  54 public int oldbot;              /* Old bottom of screen behavior {{REMOVE}} */
  55 public int opt_use_backslash;   /* Use backslash escaping in option parsing */
  56 public char rscroll_char;       /* Char which marks chopped lines with -S */
  57 public int rscroll_attr;        /* Attribute of rscroll_char */
  58 public int no_hist_dups;        /* Remove dups from history list */
  59 public int mousecap;            /* Allow mouse for scrolling */
  60 public int wheel_lines;         /* Number of lines to scroll on mouse wheel scroll */
  61 public int perma_marks;         /* Save marks in history file */
  62 public int linenum_width;       /* Width of line numbers */
  63 public int status_col_width;    /* Width of status column */
  64 public int incr_search;         /* Incremental search */
  65 public int use_color;           /* Use UI color */
  66 public int want_filesize;       /* Scan to EOF if necessary to get file size */
  67 public int status_line;         /* Highlight entire marked lines */
  68 public int header_lines;        /* Freeze header lines at top of screen */
  69 public int header_cols;         /* Freeze header columns at left of screen */
  70 public int nonum_headers;       /* Don't give headers line numbers */
  71 public int redraw_on_quit;      /* Redraw last screen after term deinit */
  72 public int def_search_type;     /* */
  73 public int exit_F_on_close;     /* Exit F command when input closes */
  74 #if HILITE_SEARCH
  75 public int hilite_search;       /* Highlight matched search patterns? */
  76 #endif
  77
  78 public int less_is_more = 0;    /* Make compatible with POSIX more */
  79
  80 /*
  81  * Long option names.
  82  */
  83 static struct optname a_optname      = { "search-skip-screen",   NULL };
  84 static struct optname b_optname      = { "buffers",              NULL };
  85 static struct optname B__optname     = { "auto-buffers",         NULL };
  86 static struct optname c_optname      = { "clear-screen",         NULL };
  87 static struct optname d_optname      = { "dumb",                 NULL };
  88 static struct optname D__optname     = { "color",                NULL };
  89 static struct optname e_optname      = { "quit-at-eof",          NULL };
  90 static struct optname f_optname      = { "force",                NULL };
  91 static struct optname F__optname     = { "quit-if-one-screen",   NULL };
  92 #if HILITE_SEARCH
  93 static struct optname g_optname      = { "hilite-search",        NULL };
  94 #endif
  95 static struct optname h_optname      = { "max-back-scroll",      NULL };
  96 static struct optname i_optname      = { "ignore-case",          NULL };
  97 static struct optname j_optname      = { "jump-target",          NULL };
  98 static struct optname J__optname     = { "status-column",        NULL };
  99 #if USERFILE
 100 static struct optname k_optname      = { "lesskey-file",         NULL };
 101 #if HAVE_LESSKEYSRC
 102 static struct optname ks_optname     = { "lesskey-src",          NULL };
 103 #endif /* HAVE_LESSKEYSRC */
 104 #endif
 105 static struct optname K__optname     = { "quit-on-intr",         NULL };
 106 static struct optname L__optname     = { "no-lessopen",          NULL };
 107 static struct optname m_optname      = { "long-prompt",          NULL };
 108 static struct optname n_optname      = { "line-numbers",         NULL };
 109 #if LOGFILE
 110 static struct optname o_optname      = { "log-file",             NULL };
 111 static struct optname O__optname     = { "LOG-FILE",             NULL };
 112 #endif
 113 static struct optname p_optname      = { "pattern",              NULL };
 114 static struct optname P__optname     = { "prompt",               NULL };
 115 static struct optname q2_optname     = { "silent",               NULL };
 116 static struct optname q_optname      = { "quiet",                &q2_optname };
 117 static struct optname r_optname      = { "raw-control-chars",    NULL };
 118 static struct optname s_optname      = { "squeeze-blank-lines",  NULL };
 119 static struct optname S__optname     = { "chop-long-lines",      NULL };
 120 #if TAGS
 121 static struct optname t_optname      = { "tag",                  NULL };
 122 static struct optname T__optname     = { "tag-file",             NULL };
 123 #endif
 124 static struct optname u_optname      = { "underline-special",    NULL };
 125 static struct optname V__optname     = { "version",              NULL };
 126 static struct optname w_optname      = { "hilite-unread",        NULL };
 127 static struct optname x_optname      = { "tabs",                 NULL };
 128 static struct optname X__optname     = { "no-init",              NULL };
 129 static struct optname y_optname      = { "max-forw-scroll",      NULL };
 130 static struct optname z_optname      = { "window",               NULL };
 131 static struct optname quote_optname  = { "quotes",               NULL };
 132 static struct optname tilde_optname  = { "tilde",                NULL };
 133 static struct optname query_optname  = { "help",                 NULL };
 134 static struct optname pound_optname  = { "shift",                NULL };
 135 static struct optname keypad_optname = { "no-keypad",            NULL };
 136 static struct optname oldbot_optname = { "old-bot",              NULL };
 137 static struct optname follow_optname = { "follow-name",          NULL };
 138 static struct optname use_backslash_optname = { "use-backslash", NULL };
 139 static struct optname rscroll_optname = { "rscroll", NULL };
 140 static struct optname nohistdups_optname = { "no-histdups",      NULL };
 141 static struct optname mousecap_optname = { "mouse",              NULL };
 142 static struct optname wheel_lines_optname = { "wheel-lines",     NULL };
 143 static struct optname perma_marks_optname = { "save-marks",      NULL };
 144 static struct optname linenum_width_optname = { "line-num-width", NULL };
 145 static struct optname status_col_width_optname = { "status-col-width", NULL };
 146 static struct optname incr_search_optname = { "incsearch",       NULL };
 147 static struct optname use_color_optname = { "use-color",         NULL };
 148 static struct optname want_filesize_optname = { "file-size",     NULL };
 149 static struct optname status_line_optname = { "status-line",     NULL };
 150 static struct optname header_optname = { "header",               NULL };
 151 static struct optname nonum_headers_optname = { "no-number-headers", NULL };
 152 static struct optname redraw_on_quit_optname = { "redraw-on-quit", NULL };
 153 static struct optname search_type_optname = { "search-options", NULL };
 154 static struct optname exit_F_on_close_optname = { "exit-follow-on-close", NULL };
 155 #if LESSTEST
 156 static struct optname ttyin_name_optname = { "tty",              NULL };
 157 static struct optname rstat_optname  = { "rstat",                NULL };
 158 #endif /*LESSTEST*/
 159
 160
 161 /*
 162  * Table of all options and their semantics.
 163  *
 164  * For BOOL and TRIPLE options, odesc[0], odesc[1], odesc[2] are
 165  * the description of the option when set to 0, 1 or 2, respectively.
 166  * For NUMBER options, odesc[0] is the prompt to use when entering
 167  * a new value, and odesc[1] is the description, which should contain
 168  * one %d which is replaced by the value of the number.
 169  * For STRING options, odesc[0] is the prompt to use when entering
 170  * a new value, and odesc[1], if not NULL, is the set of characters
 171  * that are valid in the string.
 172  */
 173 static struct loption option[] =
 174 {
 175         { 'a', &a_optname,
 176                 TRIPLE, OPT_ONPLUS, &how_search, NULL,
 177                 {
 178                         "Search includes displayed screen",
 179                         "Search skips displayed screen",
 180                         "Search includes all of displayed screen"
 181                 }
 182         },
 183
 184         { 'b', &b_optname,
 185                 NUMBER|INIT_HANDLER, 64, &bufspace, opt_b,
 186                 {
 187                         "Max buffer space per file (K): ",
 188                         "Max buffer space per file: %dK",
 189                         NULL
 190                 }
 191         },
 192         { 'B', &B__optname,
 193                 BOOL, OPT_ON, &autobuf, NULL,
 194                 {
 195                         "Don't automatically allocate buffers",
 196                         "Automatically allocate buffers when needed",
 197                         NULL
 198                 }
 199         },
 200         { 'c', &c_optname,
 201                 TRIPLE, OPT_OFF, &top_scroll, NULL,
 202                 {
 203                         "Repaint by scrolling from bottom of screen",
 204                         "Repaint by painting from top of screen",
 205                         "Repaint by painting from top of screen"
 206                 }
 207         },
 208         { 'd', &d_optname,
 209                 BOOL|NO_TOGGLE, OPT_OFF, &know_dumb, NULL,
 210                 {
 211                         "Assume intelligent terminal",
 212                         "Assume dumb terminal",
 213                         NULL
 214                 }
 215         },
 216         { 'D', &D__optname,
 217                 STRING|REPAINT|NO_QUERY, 0, NULL, opt_D,
 218                 {
 219                         "color desc: ",
 220                         NULL,
 221                         NULL
 222                 }
 223         },
 224         { 'e', &e_optname,
 225                 TRIPLE, OPT_OFF, &quit_at_eof, NULL,
 226                 {
 227                         "Don't quit at end-of-file",
 228                         "Quit at end-of-file",
 229                         "Quit immediately at end-of-file"
 230                 }
 231         },
 232         { 'f', &f_optname,
 233                 BOOL, OPT_OFF, &force_open, NULL,
 234                 {
 235                         "Open only regular files",
 236                         "Open even non-regular files",
 237                         NULL
 238                 }
 239         },
 240         { 'F', &F__optname,
 241                 BOOL, OPT_OFF, &quit_if_one_screen, NULL,
 242                 {
 243                         "Don't quit if end-of-file on first screen",
 244                         "Quit if end-of-file on first screen",
 245                         NULL
 246                 }
 247         },
 248 #if HILITE_SEARCH
 249         { 'g', &g_optname,
 250                 TRIPLE|HL_REPAINT, OPT_ONPLUS, &hilite_search, NULL,
 251                 {
 252                         "Don't highlight search matches",
 253                         "Highlight matches for previous search only",
 254                         "Highlight all matches for previous search pattern",
 255                 }
 256         },
 257 #endif
 258         { 'h', &h_optname,
 259                 NUMBER, -1, &back_scroll, NULL,
 260                 {
 261                         "Backwards scroll limit: ",
 262                         "Backwards scroll limit is %d lines",
 263                         NULL
 264                 }
 265         },
 266         { 'i', &i_optname,
 267                 TRIPLE|HL_REPAINT, OPT_OFF, &caseless, opt_i,
 268                 {
 269                         "Case is significant in searches",
 270                         "Ignore case in searches",
 271                         "Ignore case in searches and in patterns"
 272                 }
 273         },
 274         { 'j', &j_optname,
 275                 STRING, 0, NULL, opt_j,
 276                 {
 277                         "Target line: ",
 278                         "0123456789.-",
 279                         NULL
 280                 }
 281         },
 282         { 'J', &J__optname,
 283                 BOOL|REPAINT, OPT_OFF, &status_col, NULL,
 284                 {
 285                         "Don't display a status column",
 286                         "Display a status column",
 287                         NULL
 288                 }
 289         },
 290 #if USERFILE
 291         { 'k', &k_optname,
 292                 STRING|NO_TOGGLE|NO_QUERY, 0, NULL, opt_k,
 293                 { NULL, NULL, NULL }
 294         },
 295 #if HAVE_LESSKEYSRC
 296         { OLETTER_NONE, &ks_optname,
 297                 STRING|NO_TOGGLE|NO_QUERY, 0, NULL, opt_ks,
 298                 { NULL, NULL, NULL }
 299         },
 300 #endif /* HAVE_LESSKEYSRC */
 301 #endif
 302         { 'K', &K__optname,
 303                 BOOL, OPT_OFF, &quit_on_intr, NULL,
 304                 {
 305                         "Interrupt (ctrl-C) returns to prompt",
 306                         "Interrupt (ctrl-C) exits less",
 307                         NULL
 308                 }
 309         },
 310         { 'L', &L__optname,
 311                 BOOL, OPT_ON, &use_lessopen, NULL,
 312                 {
 313                         "Don't use the LESSOPEN filter",
 314                         "Use the LESSOPEN filter",
 315                         NULL
 316                 }
 317         },
 318         { 'm', &m_optname,
 319                 TRIPLE, OPT_OFF, &pr_type, NULL,
 320                 {
 321                         "Short prompt",
 322                         "Medium prompt",
 323                         "Long prompt"
 324                 }
 325         },
 326         { 'n', &n_optname,
 327                 TRIPLE|REPAINT, OPT_ON, &linenums, NULL,
 328                 {
 329                         "Don't use line numbers",
 330                         "Use line numbers",
 331                         "Constantly display line numbers"
 332                 }
 333         },
 334 #if LOGFILE
 335         { 'o', &o_optname,
 336                 STRING, 0, NULL, opt_o,
 337                 { "log file: ", NULL, NULL }
 338         },
 339         { 'O', &O__optname,
 340                 STRING, 0, NULL, opt__O,
 341                 { "Log file: ", NULL, NULL }
 342         },
 343 #endif
 344         { 'p', &p_optname,
 345                 STRING|NO_TOGGLE|NO_QUERY, 0, NULL, opt_p,
 346                 { NULL, NULL, NULL }
 347         },
 348         { 'P', &P__optname,
 349                 STRING, 0, NULL, opt__P,
 350                 { "prompt: ", NULL, NULL }
 351         },
 352         { 'q', &q_optname,
 353                 TRIPLE, OPT_OFF, &quiet, NULL,
 354                 {
 355                         "Ring the bell for errors AND at eof/bof",
 356                         "Ring the bell for errors but not at eof/bof",
 357                         "Never ring the bell"
 358                 }
 359         },
 360         { 'r', &r_optname,
 361                 TRIPLE|REPAINT, OPT_OFF, &ctldisp, NULL,
 362                 {
 363                         "Display control characters as ^X",
 364                         "Display control characters directly (not recommended)",
 365                         "Display ANSI sequences directly, other control characters as ^X"
 366                 }
 367         },
 368         { 's', &s_optname,
 369                 BOOL|REPAINT, OPT_OFF, &squeeze, NULL,
 370                 {
 371                         "Display all blank lines",
 372                         "Squeeze multiple blank lines",
 373                         NULL
 374                 }
 375         },
 376         { 'S', &S__optname,
 377                 BOOL|REPAINT, OPT_OFF, &chopline, NULL,
 378                 {
 379                         "Fold long lines",
 380                         "Chop long lines",
 381                         NULL
 382                 }
 383         },
 384 #if TAGS
 385         { 't', &t_optname,
 386                 STRING|NO_QUERY, 0, NULL, opt_t,
 387                 { "tag: ", NULL, NULL }
 388         },
 389         { 'T', &T__optname,
 390                 STRING, 0, NULL, opt__T,
 391                 { "tags file: ", NULL, NULL }
 392         },
 393 #endif
 394         { 'u', &u_optname,
 395                 TRIPLE|REPAINT, OPT_OFF, &bs_mode, NULL,
 396                 {
 397                         "Display underlined text in underline mode",
 398                         "Backspaces cause overstrike",
 399                         "Print backspace as ^H"
 400                 }
 401         },
 402         { 'V', &V__optname,
 403                 NOVAR, 0, NULL, opt__V,
 404                 { NULL, NULL, NULL }
 405         },
 406         { 'w', &w_optname,
 407                 TRIPLE|REPAINT, OPT_OFF, &show_attn, NULL,
 408                 {
 409                         "Don't highlight first unread line",
 410                         "Highlight first unread line after forward-screen",
 411                         "Highlight first unread line after any forward movement",
 412                 }
 413         },
 414         { 'x', &x_optname,
 415                 STRING|REPAINT, 0, NULL, opt_x,
 416                 {
 417                         "Tab stops: ",
 418                         "0123456789,",
 419                         NULL
 420                 }
 421         },
 422         { 'X', &X__optname,
 423                 BOOL|NO_TOGGLE, OPT_OFF, &no_init, NULL,
 424                 {
 425                         "Send init/deinit strings to terminal",
 426                         "Don't use init/deinit strings",
 427                         NULL
 428                 }
 429         },
 430         { 'y', &y_optname,
 431                 NUMBER, -1, &forw_scroll, NULL,
 432                 {
 433                         "Forward scroll limit: ",
 434                         "Forward scroll limit is %d lines",
 435                         NULL
 436                 }
 437         },
 438         { 'z', &z_optname,
 439                 NUMBER, -1, &swindow, NULL,
 440                 {
 441                         "Scroll window size: ",
 442                         "Scroll window size is %d lines",
 443                         NULL
 444                 }
 445         },
 446         { '"', &quote_optname,
 447                 STRING, 0, NULL, opt_quote,
 448                 { "quotes: ", NULL, NULL }
 449         },
 450         { '~', &tilde_optname,
 451                 BOOL|REPAINT, OPT_ON, &twiddle, NULL,
 452                 {
 453                         "Don't show tildes after end of file",
 454                         "Show tildes after end of file",
 455                         NULL
 456                 }
 457         },
 458         { '?', &query_optname,
 459                 NOVAR, 0, NULL, opt_query,
 460                 { NULL, NULL, NULL }
 461         },
 462         { '#', &pound_optname,
 463                 STRING, 0, NULL, opt_shift,
 464                 {
 465                         "Horizontal shift: ",
 466                         "0123456789.",
 467                         NULL
 468                 }
 469         },
 470         { OLETTER_NONE, &keypad_optname,
 471                 BOOL|NO_TOGGLE, OPT_OFF, &no_keypad, NULL,
 472                 {
 473                         "Use keypad mode",
 474                         "Don't use keypad mode",
 475                         NULL
 476                 }
 477         },
 478         { OLETTER_NONE, &oldbot_optname,
 479                 BOOL, OPT_OFF, &oldbot, NULL,
 480                 {
 481                         "Use new bottom of screen behavior",
 482                         "Use old bottom of screen behavior",
 483                         NULL
 484                 }
 485         },
 486         { OLETTER_NONE, &follow_optname,
 487                 BOOL, FOLLOW_DESC, &follow_mode, NULL,
 488                 {
 489                         "F command follows file descriptor",
 490                         "F command follows file name",
 491                         NULL
 492                 }
 493         },
 494         { OLETTER_NONE, &use_backslash_optname,
 495                 BOOL, OPT_OFF, &opt_use_backslash, NULL,
 496                 {
 497                         "Use backslash escaping in command line parameters",
 498                         "Don't use backslash escaping in command line parameters",
 499                         NULL
 500                 }
 501         },
 502         { OLETTER_NONE, &rscroll_optname,
 503                 STRING|REPAINT|INIT_HANDLER, 0, NULL, opt_rscroll,
 504                 { "right scroll character: ", NULL, NULL }
 505         },
 506         { OLETTER_NONE, &nohistdups_optname,
 507                 BOOL, OPT_OFF, &no_hist_dups, NULL,
 508                 {
 509                         "Allow duplicates in history list",
 510                         "Remove duplicates from history list",
 511                         NULL
 512                 }
 513         },
 514         { OLETTER_NONE, &mousecap_optname,
 515                 TRIPLE, OPT_OFF, &mousecap, opt_mousecap,
 516                 {
 517                         "Ignore mouse input",
 518                         "Use the mouse for scrolling",
 519                         "Use the mouse for scrolling (reverse)"
 520                 }
 521         },
 522         { OLETTER_NONE, &wheel_lines_optname,
 523                 NUMBER|INIT_HANDLER, 0, &wheel_lines, opt_wheel_lines,
 524                 {
 525                         "Lines to scroll on mouse wheel: ",
 526                         "Scroll %d line(s) on mouse wheel",
 527                         NULL
 528                 }
 529         },
 530         { OLETTER_NONE, &perma_marks_optname,
 531                 BOOL, OPT_OFF, &perma_marks, NULL,
 532                 {
 533                         "Don't save marks in history file",
 534                         "Save marks in history file",
 535                         NULL
 536                 }
 537         },
 538         { OLETTER_NONE, &linenum_width_optname,
 539                 NUMBER|REPAINT, MIN_LINENUM_WIDTH, &linenum_width, opt_linenum_width,
 540                 {
 541                         "Line number width: ",
 542                         "Line number width is %d chars",
 543                         NULL
 544                 }
 545         },
 546         { OLETTER_NONE, &status_col_width_optname,
 547                 NUMBER|REPAINT, 2, &status_col_width, opt_status_col_width,
 548                 {
 549                         "Status column width: ",
 550                         "Status column width is %d chars",
 551                         NULL
 552                 }
 553         },
 554         { OLETTER_NONE, &incr_search_optname,
 555                 BOOL, OPT_OFF, &incr_search, NULL,
 556                 {
 557                         "Incremental search is off",
 558                         "Incremental search is on",
 559                         NULL
 560                 }
 561         },
 562         { OLETTER_NONE, &use_color_optname,
 563                 BOOL|REPAINT, OPT_OFF, &use_color, NULL,
 564                 {
 565                         "Don't use color",
 566                         "Use color",
 567                         NULL
 568                 }
 569         },
 570         { OLETTER_NONE, &want_filesize_optname,
 571                 BOOL|REPAINT, OPT_OFF, &want_filesize, opt_filesize,
 572                 {
 573                         "Don't get size of each file",
 574                         "Get size of each file",
 575                         NULL
 576                 }
 577         },
 578         { OLETTER_NONE, &status_line_optname,
 579                 BOOL|REPAINT, OPT_OFF, &status_line, NULL,
 580                 {
 581                         "Don't color each line with its status column color",
 582                         "Color each line with its status column color",
 583                         NULL
 584                 }
 585         },
 586         { OLETTER_NONE, &header_optname,
 587                 STRING|REPAINT, 0, NULL, opt_header,
 588                 {
 589                         "Header lines: ",
 590                         NULL,
 591                         NULL
 592                 }
 593         },
 594         { OLETTER_NONE, &nonum_headers_optname,
 595                 BOOL|REPAINT, 0, &nonum_headers, NULL,
 596                 {
 597                         "Number header lines",
 598                         "Don't number header lines",
 599                         NULL
 600                 }
 601         },
 602         { OLETTER_NONE, &redraw_on_quit_optname,
 603                 BOOL, OPT_OFF, &redraw_on_quit, NULL,
 604                 {
 605                         "Don't redraw screen when quitting",
 606                         "Redraw last screen when quitting",
 607                         NULL
 608                 }
 609         },
 610         { OLETTER_NONE, &search_type_optname,
 611                 STRING, 0, NULL, opt_search_type,
 612                 {
 613                         "Search options: ",
 614                         NULL,
 615                         NULL
 616                 }
 617         },
 618         { OLETTER_NONE, &exit_F_on_close_optname,
 619                 BOOL, OPT_OFF, &exit_F_on_close, NULL,
 620                 {
 621                         "Don't exit F command when input closes",
 622                         "Exit F command when input closes",
 623                         NULL
 624                 }
 625         },
 626 #if LESSTEST
 627         { OLETTER_NONE, &ttyin_name_optname,
 628                 STRING|NO_TOGGLE, 0, NULL, opt_ttyin_name,
 629                 {
 630                         NULL,
 631                         NULL,
 632                         NULL
 633                 }
 634         },
 635         { OLETTER_NONE, &rstat_optname,
 636                 STRING|NO_TOGGLE, 0, NULL, opt_rstat,
 637                 {
 638                         NULL,
 639                         NULL,
 640                         NULL
 641                 }
 642         },
 643 #endif /*LESSTEST*/
 644         { '\0', NULL, NOVAR, 0, NULL, NULL, { NULL, NULL, NULL } }
 645 };
 646
 647
 648 /*
 649  * Initialize each option to its default value.
 650  */
 651         public void
 652 init_option(VOID_PARAM)
 653 {
 654         struct loption *o;
 655         char *p;
 656
 657         p = lgetenv("LESS_IS_MORE");
 658         if (!isnullenv(p))
 659                 less_is_more = 1;
 660
 661         for (o = option;  o->oletter != '\0';  o++)
 662         {
 663                 /*
 664                  * Set each variable to its default.
 665                  */
 666                 if (o->ovar != NULL)
 667                         *(o->ovar) = o->odefault;
 668                 if (o->otype & INIT_HANDLER)
 669                         (*(o->ofunc))(INIT, (char *) NULL);
 670         }
 671 }
 672
 673 /*
 674  * Find an option in the option table, given its option letter.
 675  */
 676         public struct loption *
 677 findopt(c)
 678         int c;
 679 {
 680         struct loption *o;
 681
 682         for (o = option;  o->oletter != '\0';  o++)
 683         {
 684                 if (o->oletter == c)
 685                         return (o);
 686                 if ((o->otype & TRIPLE) && ASCII_TO_UPPER(o->oletter) == c)
 687                         return (o);
 688         }
 689         return (NULL);
 690 }
 691
 692 /*
 693  *
 694  */
 695         static int
 696 is_optchar(c)
 697         char c;
 698 {
 699         if (ASCII_IS_UPPER(c))
 700                 return 1;
 701         if (ASCII_IS_LOWER(c))
 702                 return 1;
 703         if (c == '-')
 704                 return 1;
 705         return 0;
 706 }
 707
 708 /*
 709  * Find an option in the option table, given its option name.
 710  * p_optname is the (possibly partial) name to look for, and
 711  * is updated to point after the matched name.
 712  * p_oname if non-NULL is set to point to the full option name.
 713  */
 714         public struct loption *
 715 findopt_name(p_optname, p_oname, p_err)
 716         char **p_optname;
 717         char **p_oname;
 718         int *p_err;
 719 {
 720         char *optname = *p_optname;
 721         struct loption *o;
 722         struct optname *oname;
 723         int len;
 724         int uppercase;
 725         struct loption *maxo = NULL;
 726         struct optname *maxoname = NULL;
 727         int maxlen = 0;
 728         int ambig = 0;
 729         int exact = 0;
 730
 731         /*
 732          * Check all options.
 733          */
 734         for (o = option;  o->oletter != '\0';  o++)
 735         {
 736                 /*
 737                  * Check all names for this option.
 738                  */
 739                 for (oname = o->onames;  oname != NULL;  oname = oname->onext)
 740                 {
 741                         /*
 742                          * Try normal match first (uppercase == 0),
 743                          * then, then if it's a TRIPLE option,
 744                          * try uppercase match (uppercase == 1).
 745                          */
 746                         for (uppercase = 0;  uppercase <= 1;  uppercase++)
 747                         {
 748                                 len = sprefix(optname, oname->oname, uppercase);
 749                                 if (len <= 0 || is_optchar(optname[len]))
 750                                 {
 751                                         /*
 752                                          * We didn't use all of the option name.
 753                                          */
 754                                         continue;
 755                                 }
 756                                 if (!exact && len == maxlen)
 757                                         /*
 758                                          * Already had a partial match,
 759                                          * and now there's another one that
 760                                          * matches the same length.
 761                                          */
 762                                         ambig = 1;
 763                                 else if (len > maxlen)
 764                                 {
 765                                         /*
 766                                          * Found a better match than
 767                                          * the one we had.
 768                                          */
 769                                         maxo = o;
 770                                         maxoname = oname;
 771                                         maxlen = len;
 772                                         ambig = 0;
 773                                         exact = (len == (int)strlen(oname->oname));
 774                                 }
 775                                 if (!(o->otype & TRIPLE))
 776                                         break;
 777                         }
 778                 }
 779         }
 780         if (ambig)
 781         {
 782                 /*
 783                  * Name matched more than one option.
 784                  */
 785                 if (p_err != NULL)
 786                         *p_err = OPT_AMBIG;
 787                 return (NULL);
 788         }
 789         *p_optname = optname + maxlen;
 790         if (p_oname != NULL)
 791                 *p_oname = maxoname == NULL ? NULL : maxoname->oname;
 792         return (maxo);
 793 }