Function getpatt

other_src/lua/src/lpeg.cpp:1251–1312

static Instruction *getpatt (lua_State *L, int idx, int *size) {
  Instruction *p;
  switch (lua_type(L, idx)) {
    case LUA_TSTRING: {
      size_t i, len;
      const char *s = lua_tolstring(L, idx, &len);
      p = newpatt(L, len);
      for (i = 0; i < len; i++)
        setinstaux(p + i, IChar, 0, (byte)s[i]);
      lua_replace(L, idx);
      break;
    }
    case LUA_TNUMBER: {
      int n = lua_tointeger(L, idx);
      if (n == 0)  /* empty pattern? */
        p = newpatt(L, 0);
      else if (n > 0)
        p = any(L, n, 0, NULL);
      else if (-n <= UCHAR_MAX) {
        p = newpatt(L, 2);
        setinstaux(p, IAny, 2, -n);
        setinst(p + 1, IFail, 0);
      }
      else {
        int offset = 2;  /* space for ITestAny & IChoice */
        p = any(L, -n - UCHAR_MAX, 3, &offset);
        setinstaux(p, IAny, offset + 1, UCHAR_MAX);
        setinstaux(p + 1, IChoice, offset, UCHAR_MAX);
        setinst(p + offset, IFailTwice, 0);
      }
      lua_replace(L, idx);
      break;
    }
    case LUA_TBOOLEAN: {
      if (lua_toboolean(L, idx))  /* true? */
        p = newpatt(L, 0);  /* empty pattern (always succeeds) */
      else {
        p = newpatt(L, 1);
        setinst(p, IFail, 0);
      }
      lua_replace(L, idx);
      break;
    }
    case LUA_TTABLE: {
      p = fix_l(L, idx);
      break;
    }
    case LUA_TFUNCTION: {
      p = newpatt(L, 2);
      setinstcap(p, IOpenCapture, value2fenv(L, idx), Cruntime, 0);
      setinstcap(p + 1, ICloseRunTime, 0, Cclose, 0);
      lua_replace(L, idx);
      break;
    }
    default: {
      p = checkpattern(L, idx);
      break;
    }