Re: Substring expansion error when offset contains a colon

[Chet Ramey]

On 10/19/15 3:45 AM, grishalevit@gmail.com wrote:
> When using ${parameter:offset:length} expansion, the parser doesn't account 
> for all the ways that a colon can appear in "offset".
> 
> For example:
> 
> $ echo ${PARAM:${OFFSET:-0}}
> -bash: ${OFFSET: bad substitution
> 
> or:
> 
> # declare -A A=([a:b]=0)
> # echo ${PARAM:${A[a:b]}}
> -bash: ${A[a: bad substitution
> 
> It seems that the issue is in the use of skiparith in 
> verify_substring_values.  Switching to to skip_to_delim removes this issue.  
> The ${parameter/pattern/string} expansion uses skip_to_delim to search for 
> the second '/' so I suspect it's use is appropriate here as well.

It's not quite that simple.  The reason skiparith() is used is that
arithmetic expressions may contain a colon (test?exp1:exp2), so skiparith
skips over one colon for each `?'.  I will have to figure out a way to
continue to support this syntax for backwards compatibility and allow for
colons in other contexts.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/