Re: table.concat and metamethods

[Dirk Laurie <dirk.laurie@...>]

I append a patch that makes table.concat respect the __concat
metamethod.  It corrects a bug in the version posted on 2012/6/27
and also behaves like Lua always has, rather than how it said in the
manual it does.  The difference is significant when a table contains only
one item and that item is not a string, as described below.

2012/6/28 Dirk Laurie <dirk.laurie@gmail.com>:
>
> BTW the manual is not quite correct — that expression reduces to
> table[1] when #table==1, which may be a number, whereas
> table.concat always returns a string. The official Lua source code
> actually evaluates the equivalent of
>
>          ""..table[i]..sep..table[i+1] ··· sep..table[j]
>
> by a method applicable only to table entries for which lua_isstring is
> true.

For the combination of this feature with a particular definition of __concat
for strings, see the earlier posts in the thread.

For the license-conscious: this is public-domain code.

Dirk

Attachment: tconcat.patch
Description: Binary data