On Wed, May 22, 2013 at 9:51 PM, Irek Szczesniak <[email protected]> wrote:
> On Wed, May 22, 2013 at 9:31 PM, Dan Douglas <[email protected]> wrote:
>> On Tue, May 21, 2013 at 3:51 AM, Roland Mainz <[email protected]> 
>> wrote:
>>> Hi!
>>>
>>> ----
>>>
>>> Attached (as "astksh20130503_typeset_copy_operator001.diff.txt") is a
>>> small patch which provides a type-independent copy-by-name operator.
>>
>> Why are typeset options required to move/copy objects?
>
> typeset -m destname=srcname # move/rename variable
> typeset -c destname=srcname # copy variable
>
>> Don't namerefs
>> on positional parameters create reference variables (`&arg'/`ref arg'
>> from C++/C#) that refer directly to an object right?
>
> I don't grok this. Can you give an example, please?
>
>> If not ksh should
>> really have an explicit dereference operator instead.
>
> ksh93 has a dereference operator: ${!varname} returns the name a
> nameref is referring to.
>
>> `typeset -c' conflicts with Bash's (undocumented) "capcase" feature.
>
> 1. Its undocumented in bash(1). It never was and AFAIK never will be
> because it was an experiment
> 2. I can't find any scripts which use this feature, and in the light
> of ksh93's typeset -M it is redundant
> 3. Its not working properly outside ASCII (you can verify that the
> generated multibyte characters are garbage through AST wc -X)
> 4. ksh93 is not bash
> 5. typeset -m and typeset -c is much more useful than another damn
> make characters uppercase feature which can be implemented much easier
> through typeset -M, disciplines or other means
>
>> Also ksh fails on most of your examples if wrapped in a namespace.
>
> Yes, I noticed a few bugs. But if you follow the
> [email protected] closely you'll see that Roland is
> reporting bugs as they are found and per Roland's feedback on my own
> bug reports David Korn is fixing them for the next ast-ksh alpha. So
> no worries :)

To clarify my point: I *like* the idea of having a generic
variable/array/type copying facility implemented using typeset -c. IMO
it is very very useful and simplifies *many* otherwise complex
programming tasks.

Irek
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