io_lib:format and ++

[Hal Snyder]

Kent Boortz <kent@REDACTED> writes:

> This is a feature. From the reference manual
> 
>   MODULE
>        io_lib - IO Library Functions
> 
>   DESCRIPTION
>        This module contains functions for converting  to  and  from
>        strings  (lists of characters). They are used for implement-
>        ing the functions in the io module. There  is  no  guarantee
>        that the character lists returned from some of the functions
>        are flat, they can be deep lists.  lists:flatten/1  is  used
>        for generating flat lists.

Aargh. Thank you for the quick reply.

I looked in the io_lib manual, really, but was skipping straight to
the section on format, not reading the DESCRIPTION at the top.