[tarantool-patches] Re: [PATCH v2 5/5] lua: introduce utf8 built-in globaly visible module

[Alexander Turenko <alexander.turenko@tarantool.org>]

On Sat, May 05, 2018 at 03:24:41AM +0300, Vladislav Shpilevoy wrote:
> 
> 
> > 
> > > > > +
> > > > > +/**
> > > > > + * Calculate length of a UTF8 string. Length here is symbol count.
> > > > > + * Works like utf8.len in Lua 5.3.
> > > > > + * @param String to get length.
> > > > > + * @param Start byte offset. Must point to the start of symbol. On
> > > > > + *        invalid symbol an error is returned. Can be negative.
> > > > 
> > > > Can be 1 <= |start| <= #str + 1, right? Is it worth to document? Such
> > > > offset equilibristics is not very intuitive (at least for me).
> > > 
> > > No, start can be any, as well as end.
> 
> diff --git a/src/lua/utf8.c b/src/lua/utf8.c
> index c31171b2c..c84e6ff72 100644
> --- a/src/lua/utf8.c
> +++ b/src/lua/utf8.c
> @@ -144,6 +144,7 @@ utf8_convert_offset(int offset, size_t len)
>   * Calculate length of a UTF8 string. Length here is symbol count.
>   * Works like utf8.len in Lua 5.3. Can take negative offsets. A
>   * negative offset is an offset from the end of string.
> + * Positive position must be inside [1, #str + 1].
>   * @param String to get length.
>   * @param Start byte offset. Must point to the start of symbol. On
>   *        invalid symbol an error is returned.
> v:tarantool v.shpilevoy$ git diff
> diff --git a/src/lua/utf8.c b/src/lua/utf8.c
> index c31171b2c..8f0ca65e5 100644
> --- a/src/lua/utf8.c
> +++ b/src/lua/utf8.c
> @@ -144,14 +144,17 @@ utf8_convert_offset(int offset, size_t len)
>   * Calculate length of a UTF8 string. Length here is symbol count.
>   * Works like utf8.len in Lua 5.3. Can take negative offsets. A
>   * negative offset is an offset from the end of string.
> + * Positive position must be inside [1, #str + 1].
>   * @param String to get length.
>   * @param Start byte offset. Must point to the start of symbol. On
>   *        invalid symbol an error is returned.
>   * @param End byte offset. Can point to the middle of symbol.
>   *        Partial symbol is counted too.
>   * @retval not nil Symbol count.
> - * @retval nil, error Error. Byte position of the error is
> + * @retval nil, number Error. Byte position of the error is
>   *         returned in the second value.
> + * @retval nil, string Error. Reason is returned in the second
> + *         value.
>   */
>  static int
>  utf8_len(struct lua_State *L)
> 
> 

[0, #str] for the end position.

Excuse me for nitpicking.

WBR, Alexander Turenko.