[GRASS-dev] error reporting

[Michael Barton]

I redid this last night to follow this model. It's in the cvs now.

Michael


On 9/7/07 1:30 PM, "Glynn Clements" <glynn at gclements.plus.com> wrote:

> 
> Michael Barton wrote:
> 
>>> If it's done here, each arg should probably be translated
>>> individually; the caller can always join any arguments which should be
>>> translated as a whole. Even then, there's no option to have a portion
>>> which doesn't get translated.
>> 
>> Like this???
>> 
>> proc Gm::errmsg { error args } {
>>     # send error report and optional message (args) to tk_messageBox
>>     set message ""
>>     for arg in $args {
>> 
>>         if { $arg != "" } {
>>             append message "$arg "
>>         }
>>     }
>> 
>>     append message ": "
>> 
>>     tk_messageBox -type ok -icon error -title [G_msg "Error"] \
>>          -message "$message[G_msg $error]"
>>     uplevel 1 return
>>       
>> };
> 
> I meant to pass each individual arg to G_msg then join the result,
> i.e. replace:
> 
>     if { $args != ""} {
>         set message [G_msg [join $args]]
>         append message ": "
>      }
> 
> with:
> 
>     if { $args != ""} {
> set trans {}
> foreach msg $args {
>    lappend trans [G_msg $msg]
> }
>         set message [G_msg [join $trans]]
>         append message ": "
>      }
> 
> 
>> You are right. A downside of enforcing translation within the function,
>> rather than relying on it to be done in the original script, is that the
>> whole thing gets translated. I'm not sure if this is really a problem with
>> short, optional error messages in reality.
> 
> The problem occurs if the error message includes variable components,
> e.g. "unable to open $filename" or "error executing $prog".
> 
> Only the fixed portions should be translated (otherwise the message
> catalogue would need an entry for every possible string), then the
> variable portions should be inserted afterwards.
> 
> If the variable portions occur in the middle of the string, you would
> want something like:
> 
> set template [G_msg {unable to open $filename for reading}]
> set message [subst -nobackslashes -nocommands $template]
> 
> Actually, this could be done in the error handling procedure, using
> "uplevel" to allow "subst" to use variables from the caller.
> 
> Ultimately, I still think that it's better to have the caller perform
> the translation. In C code, the _() macro is always applied to the
> literal string; we don't make G_fatal_error() call _().
> 
> Apart from anything else, it makes it easier to identify strings which
> require translation ("grep G_msg").

__________________________________________
Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton