Re: [Autogen-users] 'extract' Function Sets Output Files Writable - Feature, not Bug.

[Eric M. <mcd...@ph...>]

Thanks for the explanation, Bruce. What you say does make sense from the
perspective you were approaching it.

I guess I was approaching it from a slightly different angle (i.e.,
pulling in pieces of other files to create a generated, non-editable
"Frankenfile"). Maybe there is a better approach for what I am trying to
do. (There is no definitions file for the use case I have in mind - just
portions of a bunch of other generated files to merge with the
template.) However, it looks like --not-writable will do the trick. Thanks.

Regards,
  Eric

Bruce Korb wrote:
> On Sat, Oct 3, 2009 at 4:00 PM, Eric McDonald <mcd...@ph...> wrote:
>> Hi,
>>
>>  I've noticed that the output files from templates, which use the
>> 'extract' Autogen Scheme function, are set to writable. Looking at the
>> 'loadExtractData' function in agen5/expExtract.c, I can see that this
>> appears to be deliberate:
>>
>>      if (! HAVE_OPT( WRITABLE ))
>>        SET_OPT_WRITABLE;
>>
>> I am having trouble understanding why this is desirable. I read the
>> documentation for the 'extract' function, as well as the comments in its
>> implementation, and nothing really stands out as a reason. Even if the
>> output files are not going to be kept around long-term, as in the case
>> of the example code mentioned in the documentation, they should still be
>> able to get forcefully renamed or removed. Hence, it should be safe to
>> leave them read-only by default.
>>
>>  Any insights?
> 
> The theory behind it is that if you are extracting something from the previous
> incarnation of the same file, then your client wants to be able to edit the
> text that was extracted.  Witness the file agen5/cgi-fsm.c:
> 
>         case CGI_TR_NAME_EQUAL:
>             /* START == NAME_EQUAL == DO NOT CHANGE THIS COMMENT */
>             strcpy( pzOut, "='" );
>             outlen -= 2;
>             pzOut += 2;
>             /* END   == NAME_EQUAL == DO NOT CHANGE THIS COMMENT */
>             break;
> 
> The code between the "START" and "END" is hand crafted.
> The rest changes if my FSM state machine template changes.
> This is in line with what is done by GUI code generators, for example.
> If you use the option, ``--not-writable'', then loadExtractData will not
> force the output to be writable.  (You "have" the option and it was set
> to the disabled state.)
> 
> I will augment the doc for "extract".  Thanks!  Regards, Bruce