autocomplete.d

   1 /* Invisible Vector Library
   2  * coded by Ketmar // Invisible Vector <ketmar@ketmar.no-ip.org>
   3  * Understanding is not required. Only obedience.
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, version 3 of the License ONLY.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 module iv.autocomplete is aliced;
  18
  19 import iv.alice;
  20
  21
  22 /**
  23  * Build list of suitable autocompletions.
  24  *
  25  * Params:
  26  *  cmd = user-given command prefix
  27  *  cmdlist = list of all available commands
  28  *
  29  * Returns:
  30  *  null = no matches (empty array)
  31  *  array with one item: exactly one match
  32  *  array with more that one item = [0] is max prefix, then list of autocompletes
  33  *
  34  * Throws:
  35  *  Out of memory exception
  36  */
  37 string[] autocomplete (string cmd, string[] cmdlist...) @trusted nothrow {
  38   if (cmdlist.length == 0) return [cmd];
  39   string found; // autoinit
  40   usize foundlen, pfxcount; // autoinit
  41   // ÐÅÒ×ÙÊ ÐÒÏÈÏÄ: ÓÞÉÔÁÅÍ ÐÒÅÆÉËÓÙ, ÚÁÐÏÍÉÎÁÅÍ ËÏÍÁÎÄÕ Ó ÓÁÍÙÍ ÄÌÉÎÎÙÍ ÐÒÅÆÉËÓÏÍ
  42   foreach (immutable s; cmdlist) {
  43     if (cmd.length <= s.length) {
  44       usize pos = cmd.length;
  45       foreach (immutable idx; 0..cmd.length) if (cmd[idx] != s[idx]) { pos = idx; break; }
  46       if (pos == cmd.length) {
  47         if (s.length > found.length) found = s;
  48         ++pfxcount;
  49       }
  50     }
  51   }
  52   if (pfxcount == 0) return null; // ÎÅ ÎÁÛÌÉ ×ÏÏÂÝÅ ÎÉÈÅÒÁ, ×ÁÌÉÍ ÏÔÓÀÄÁ, ÐÁÃÁÎÙ!
  53   if (pfxcount == 1) return [found]; // ÅÓÔØ ÔÏÌØËÏ ÏÄÉÎ, ÕÎÏÓÉÔÅ
  54   // ÎÁÛÌÉ ÄÏÈÅÒÁ, ÜÔÏ ÐÒÉÓËÏÒÂÎÏ
  55   // ÉÝÅÍ ÓÁÍÙÊ ÄÌÉÎÎÙÊ ÐÒÅÆÉËÓ ÉÚ ×ÏÚÍÏÖÎÙÈ, ÚÁÏÄÎÏ ÓÏÂÉÒÁÅÍ ×Ó£, ÞÔÏ ÍÏÖÎÏ
  56   string[] res = new string[pfxcount+1]; // ÓÀÄÁ ÓÌÏÖÉÍ ×Ó£ ÐÏÄÈÏÄÑÝÅÅ; ÍÙ ÔÏÞÎÏ ÚÎÁÅÍ, ÓËÏÌØËÏ ÉÈ ÂÕÄÅÔ
  57   usize respos = 1; // res[0] -- ÓÁÍÙÊ ÄÌÉÎÎÙÊ ÐÒÅÆÉËÓ, ÎÁÞÎ£Í Ó [1]
  58   usize slen = cmd.length; // ÔÏÞÎÏ ÎÅ ÂÏÌØÛÅ found.length
  59   foreach (immutable s; cmdlist) {
  60     if (s.length >= slen) {
  61       usize pos = slen;
  62       foreach (immutable idx; 0..slen) if (found[idx] != s[idx]) { pos = idx; break; }
  63       if (pos == slen) {
  64         // ÎÁÛÅ, ÚÁÐÏÍÉÎÁÅÍ É ÐÒÁ×ÉÍ ÐÒÅÆÉËÓ
  65         res[respos++] = s;
  66         // ÏÂÒÅÚÁÅÍ ÐÏ ÍÉÎÉÍÕÍÕ, ÎÏ ÎÅ ÍÅÎØÛÅ, ÞÅÍ ÎÁÄÏ
  67         for (; pos < found.length && pos < s.length; ++pos) if (found[pos] != s[pos]) break;
  68         if (pos < found.length) {
  69           found = found[0..pos];
  70           if (slen > pos) slen = pos;
  71         }
  72       }
  73     }
  74   }
  75   // ÐÅÒ×ÙÍ ÜÌÅÍÅÎÔÏÍ ×ÓÔÁ×ÉÍ ÍÁËÓÉÍÁÌØÎÙÊ ÐÒÅÆÉËÓ
  76   res[0] = found;
  77   // ×Ó£
  78   return res;
  79 }
  80
  81
  82 unittest {
  83   import std.stdio;
  84   {
  85     static immutable string[3] clist0 = ["aaz", "aabed", "aand"];
  86     //writeln("--------");
  87     assert(autocomplete("", clist0) == ["aa", "aaz", "aabed", "aand"]);
  88     assert(autocomplete("a", clist0) == ["aa", "aaz", "aabed", "aand"]);
  89     assert(autocomplete("aa", clist0) == ["aa", "aaz", "aabed", "aand"]);
  90     assert(autocomplete("aab", clist0) == ["aabed"]);
  91   }
  92   {
  93     static immutable string[3] clist1 = ["az", "abed", "and"];
  94     //writeln("--------");
  95     assert(autocomplete("", clist1) == ["a", "az", "abed", "and"]);
  96     assert(autocomplete("a", clist1) == ["a", "az", "abed", "and"]);
  97     assert(autocomplete("aa", clist1) == []);
  98     assert(autocomplete("aab", clist1) == []);
  99   }
 100 }