Am 5/9/2011 6:40, schrieb Junio C Hamano:
> Johannes Sixt <j.sixt@xxxxxxxxxxxxx> writes:
>
>> - The behavior of quoting at the right of :- when the ${...:-...} exansion
>> appears in double-quotes was debated recently at length at the Austin
>> group (which revises the POSIX standard). You better move the expansions
>> to assignments of temporary variables,...
>
> What alternative semantics do Austin folks have in mind, by the way? Just
> declare this undefined?
Most of the debate centered around how to quote a closing brace: the
problem is that usually the backslash within double-quotes is only special
when followed by $, `, or \, therefore, it should not be possible to quote
a closing brace using \}. It turned out that different shells handled this
particular case differently. IIRC, there were also discrepancies whether
whitespace generated on the RHS of :- (or other operators) was retained or
discarded. The conclusion for us as application developers is not to
depend on too many subtle details in such a variable expansions because
the specification is too vague, shells implement it differently, and some
even get it outright wrong (as the case discovered by Kascper).
> - printf "fatal: Path '$2$3' $4, but not ${5:-'$3'}.\n" >expected &&
> - printf "Did you mean '$1:$2$3'${2:+ aka '$1:./$3'}?\n" >>expected &&
> + sq="'"
This cuts the && chain.
> + cat >expected <<-EOF &&
> + fatal: Path '$2$3' $4, but not ${5:-$sq$3$sq}.
> + Did you mean '$1:$2$3'${2:+ aka $sq$1:./$3$sq}?
> + EOF
Looks good otherwise; I tested this with various shells, and there were no
surprises.
-- Hannes
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