Re: Thoughts on getting correct line numbers in the byte compiler's warning messages

[Michael Heerdegen]

Alan Mackenzie <address@hidden> writes:

> Stefan's latest suggestion is to use the above approach just on symbol
> occurrences.  (Sorry!).  These are preserved through transformations
> much more than cons cells are.

BTW, just to be sure, you know about the already existing variable
`read-with-symbol-positions', right?  Only a detail for what you need to
do, though.

> If some code wants to get the starting position of a cons, the source
> code will surely be in a buffer somewhere.  As long as there is a symbol
> in the cons (i.e., we don't have ()), surely the cons position can be
> found from the contained symbol, together with backward-up-list in the
> source buffer.  Or something like that.

Sure.  The problem is how to find the right cons when several such
places exist.  Likewise for strings etc.

My requirement is quite similar to yours, btw.  Say, in a buffer at some
position there is a list (X1 X2 X3) and you want to match that with
(i.e. el-search for) pattern `(,P1 ,P2 ,P3) with certain PATTERNS Pi.
In an ideal world, when the Pi are (tried to be) matched against the Xi,
the Pi would know the buffer location of Xi, so that Pi could e.g. use a
`guard' checking the "current" value of point.

Since patterns can do destructuring like above, similar to your case I
would want the position info to somehow survive transformations (mostly
list accessing functions in my case).


Thanks,

Michael.