question about compilation-error-regexp-alist

question about compilation-error-regexp-alist

[wuxch2000]

the compile.el's comment says

"Each elt has the form (REGEXP FILE [LINE COLUMN TYPE HYPERLINK
HIGHLIGHT...]).  If REGEXP matches, the FILE'th subexpression
gives the file name, and the LINE'th subexpression gives the line
number.  The COLUMN'th subexpression gives the column number on that
line."

it's easy to understand how compile.el know FILE and LINE content, but
how can compile.el know witch TYPE the message is?

Re: question about compilation-error-regexp-alist

[Kevin Rodgers]

wuxch2000@gmail.com wrote:
> the compile.el's comment says
> 
> "Each elt has the form (REGEXP FILE [LINE COLUMN TYPE HYPERLINK
> HIGHLIGHT...]).  If REGEXP matches, the FILE'th subexpression
> gives the file name, and the LINE'th subexpression gives the line
> number.  The COLUMN'th subexpression gives the column number on that
> line."
> 
> it's easy to understand how compile.el know FILE and LINE content, but
> how can compile.el know witch TYPE the message is?

The doc string also says:

"TYPE is 2 or nil for a real error or 1 for warning or 0 for info."

So if TYPE is omitted, it is nil, thus by default the message is an error.

-- 
Kevin Rodgers

Re: question about compilation-error-regexp-alist

[wuxch2000]

thanks for your reply.

But I still do not understand how compile.el get TYPE value automatic
from matched sentence.

For example, there's a compilation-error-regexp-alist

 (edg-1
     "^\\([^ \n]+\\)(\\([0-9]+\\)):
\\(?:error\\|warnin\\(g\\)\\|remar\\(k\\)\\)"
     1 2 nil (3 . 4))

what "\\(?:error\\|warnin\\(g\\)\\|remar\\(k\\)\\)" means? why add \\(
\\) to char 'g' and 'k'?