On 03/12/2015 23:26, Harald van Dijk wrote:
> On 03/12/2015 22:17, Stephane Chazelas wrote:
>> 2015-12-03 22:02:14 +0100, Harald van Dijk:
>> [....]
>>>    $ for shell in bash mksh posh zsh; do printf %s: "$shell"; $shell
>>> -c 'IFS=,; echo a, | { read v; echo "<$v>"; }'; done
>>>    bash:<a>
>>>    mksh:<a>
>>>    posh:<a,>
>>>    zsh:<a,>
>>>
>>> As far as I can tell, the posh/zsh behaviour is the correct
>>> behaviour, but I'm not convinced yet my interpretation is correct.
>> [...]
>>
>> zsh and pdksh (and other descendants of the Forsyth shell) treat it as
>> separator (and are not compliant), mksh (derived from pdksh)
>> changed it recently. posh (also based on pdksh) still hasn't changed it.
>
> [...]
> I do see your point. Thanks for the clear example, I think I agree with
> you, the description of field splitting mentions that delimiters are
> used as terminators:
>
>    "The shell shall treat each character of the IFS as a delimiter and
> use the delimiters as field terminators to [...]"
>
> It should not be much of a problem to extend the patch I posted to cover
> the rules as you describe them, I will make an attempt at this later.

Here it is. Attached is an updated patch that ignores the complete 
terminator if only a single field remains, otherwise ignores only 
trailing IFS whitespace.

Cheers,
Harald van Dijk