Pablo Méndez Hernández said:
> Hi,
>
> On Wed, Dec 16, 2015 at 8:22 AM, Dmitrij D. Czarkoff <czark...@gmail.com>
> wrote:
>> Hi!
>>
>> I recently came across a shell script that uses idiom
>>
>> var1=var1
>> var2=var2
>> echo "${var1+($var2)}"
>>
>> ksh(1) doesn't like it:
>>
>> ksh: ${var1+($var2)}": bad substitution
>>
>> Meanwhile bash and dash just print:
>>
>> (var2)
>
> FWIW, both "regular" ksh and ksh93 in Solaris 11.2 behave the same way
> as bash and dash.
>
>> Apparently ksh tries to parse parenthesis within substituted word.
>> According to 2.2.3 Double-Quotes[1] of POSIX Shell Command Language,
>> parentheses should not be parsed within double quotes, although 2.6.2
>> Parameter Expansion[2] sets special rules for parameter substitution
>> within double quotes, and those don't mention whether substituted word
>> should be considered quoted or not.
>>
>> Patch below changes ksh's behavior to match that of bash and dash. I am
>> not decided on the matter.
>>
>> [1]
>> http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_02
>> [2]
>> http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_02
ping
>> Index: lex.c
>> ===================================================================
>> RCS file: /cvs/src/bin/ksh/lex.c,v
>> retrieving revision 1.64
>> diff -u -p -r1.64 lex.c
>> --- lex.c 18 Nov 2015 15:31:21 -0000 1.64
>> +++ lex.c 16 Dec 2015 07:05:42 -0000
>> @@ -579,6 +579,15 @@ yylex(int cf)
>> break;
>>
>> case SBRACEQ:
>> + /*{*/
>> + if (c == '}') {
>> + POP_STATE();
>> + *wp++ = CSUBST;
>> + *wp++ = /*{*/ '}';
>> + } else
>> + goto Subst;
>> + break;
>> +
>> case SBRACE:
>> /*{*/
>> if (c == '}') {
>>
--
Dmitrij D. Czarkoff
