Re: "header", "layout" and "paper" blocks as variables...

[Mats Bengtsson]

Valentin Villenave wrote:
> 2008/5/26 Mats Bengtsson <address@hidden>:
>
>   
> > Isn't the primary bug that you do get a PDF output file even though you have
> > an error in the
> > input file?
> >     
>
> Well, I won't complain about getting a PDF :-)
>   
You should, at least if you are on a Windows or Mac system where you 
process the file by
just double-clicking on the file and don't notice that LilyPond has 
discovered a serious problem,
unless you happen to look in the .log file.
In the source code, I found the following lines:
void
Input::error (string s) const
{
 message (_f ("error: %s", s));
 // UGH, fix naming or usage
 // exit (1);
}
which show that this use or mis-use of "Error: " is a known problem.
In most programs, an Error: message will also abort the program with a
non-zero exit code to show the user directly that there was a serious 
problem.

On the other hand, if you are on Windows or Mac and keep working on a 
file, you may not
notice that LilyPond exited without producing a new PDF file, since the 
previous copy of the
output still remains. The GUI mode should preferably pop up an alert 
window on the screen
in case of serious errors, to make sure that they don't pass unnoticed. 
The problem in all
implementations is to decide if an error is serious enough to deserve 
such an alert. Clearly,
all the more or less harmless "Programming error" messages you can get 
in LilyPond don't
qualify.

   /Mats