Re: [lennart.borgman.073@student.lu.se: compilation-previous-error fails if first error is at start of buffer]

["Jan Djärv" <jan.h.d@swipnet.se>]

Lennart Borgman (gmail) skrev:
> Nick Roberts wrote:
>>  > > If the compilation buffer begins with error lines right at the top:
>>  > >  > > c:/EmacsW32/etc/EmacsW32Util.html:7:5: Warning: <link> 
>> inserting "type"  > > attribute
>>  > > c:/EmacsW32/etc/EmacsW32Util.html:12:19: Warning: <table> lacks 
>>  > > "summary" attribute
>>  > > c:/EmacsW32/etc/EmacsW32Util.html:29:5: Warning: <table> lacks 
>> "summary"  > > attribute
>>  > >  > > then if point is on second line compilation-previous-error 
>> fails.
>>  > >  >  > What is the error message?
>>
>> Warnings and errors are equivalent in the compilation buffer.  I don't 
>> see how
>> Lennart gets error lines right at the top as I always get the 
>> following four
>> lines:
>>
>>     -*- mode: compilation; default-directory: "~/" -*-
>>     Compilation started at Mon Jan  8 21:22:48
>>
>>     `command used for my compilation'
> 
> 
> The output is from a library not included in Emacs (actually a version 
> of tidy.el). The output does not have the lines above at the beginning. 
> It would be rather inconvenient if it had, but maybe those line still 
> should be there for some reason?
> 

Yes there is a reason.  Compilation mode uses previous-single-property-change 
to scan backwards to find the correct position to go to.  But if a line begins 
at buffer start, there is no property change and 
previous-single-property-change return nil.

I think you should modify your library to add an empty line at the top, or 
maybe some informative text.

	Jan D.