Function pushcapture

other_src/lua/src/lpeg.cpp:2165–2229

static int pushcapture (CapState *cs) {
  luaL_checkstack(cs->L, 4, "too many captures");
  switch (captype(cs->cap)) {
    case Cposition: {
      lua_pushinteger(cs->L, cs->cap->s - cs->s + 1);
      cs->cap++;
      return 1;
    }
    case Cconst: {
      pushluaval(cs);
      cs->cap++;
      return 1;
    }
    case Carg: {
      int arg = (cs->cap++)->idx;
      if (arg + FIXEDARGS > cs->ptop)
        return luaL_error(cs->L, "reference to absent argument #%d", arg);
      lua_pushvalue(cs->L, arg + FIXEDARGS);
      return 1;
    }
    case Csimple: {
      int k = pushallvalues(cs, 1);
      if (k > 1)
        lua_insert(cs->L, -k);  /* whole match is first result */
      return k;
    }
    case Cruntime: {
      int n = 0;
      while (!isclosecap(cs->cap++)) {
        luaL_checkstack(cs->L, 4, "too many captures");
        lua_pushvalue(cs->L, (cs->cap - 1)->idx);
        n++;
      }
      return n;
    }
    case Cstring: {
      luaL_Buffer b;
      luaL_buffinit(cs->L, &b);
      stringcap(&b, cs);
      luaL_pushresult(&b);
      return 1;
    }
    case Csubst: {
      luaL_Buffer b;
      luaL_buffinit(cs->L, &b);
      substcap(&b, cs);
      luaL_pushresult(&b);
      return 1;
    }
    case Cgroup: {
      if (cs->cap->idx == 0)  /* anonymous group? */
        return pushallvalues(cs, 0);  /* add all nested values */
      else {  /* named group: add no values */
        cs->cap = nextcap(cs->cap);  /* skip capture */
        return 0;
      }
    }
    case Cbackref: return backrefcap(cs);