Re: for S'Image use Func??

["Randy Brukardt" <randy@rrsoftware.com>]

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"Yannick Duch�ne (Hibou57)" <yannick_duchene@yahoo.fr> wrote in message 
news:op.vccvt1ybxmjfy8@garhos...
Le Fri, 07 May 2010 23:27:55 +0200, Randy Brukardt <randy@rrsoftware.com>
a �crit:
...
>> It doesn't work very well, either, if you are outputting to a message box 
>> or
>> to a log manager: in both cases the entire message string has to be 
>> passed
>> at once. (That's the case in virtually all of my newer programs.) Not 
>> many
>> real programs do much output to Standard Output.
>
>There are alternatives, and here are two.
>
>The first one : the log manager could have an open/close logic to output a 
>log line.

That's what mine does, but its purpose is to serialize logging from all of 
the tasks in the system, all of which are doing their own thing without any 
special synchronization. If we tried to write parts of each message, we'd 
get a bunch of interspersed parts (or we'd have to have a very complex 
system of saving the parts inside the manager until the entire line is 
available). The other purpose is to make the logs available for inspection 
at any time (the programs in question are Windows services, so they run for 
months at a time); that's why they aren't just held open all the time.

...
> Another alternative I have used some months ago, was to use an abstraction 
> of what a text is : I was passing procedure writing text instead of 
> strings (to be exact, this was not access to procedures, this was tagged 
> types with a single method).

Interestingly, that's how the tasks find out which particular log they are 
supposed to be writing to: I pass an access-to-logging-routine.

It's also a way to do I/O from Pure/Preelaborated packages.

But you need two such routines if you plan to allow separating basic writing 
and ending of a line: New_Line is not a character, you know! (At least not 
if you are writing a portable Ada program, and want to work on many 
different targets.)

> I'm not to say this is an easy suitable for beginners (as we were also 
> talking about ease of access for beginners), I'm just exposing this as 
> example alternatives to the one-string-bulk way.

But none work very well, because you still have to identify the end of the 
line. Either you have to designate a magic character for that purpose, 
leaving Ada far behind (and also requiring scanning each string as well), or 
you need multiple routines (as Text_IO does). Whole line at a time is 
easiest, IMHO, and matches what you want to do enough of the time that there 
isn't much advantage to doing anything else. YMMV.

                   Randy.