Is there a way to do negative lookahead in vim regex?

Question

In Vim, is there a way to search for lines that match say abc but do not also contain xyz later on the line? So the following lines would match:

The abc is the best The first three letters are abc 

and the following would not match:

The abc is the best but xyz is cheaper The first three letters are abc and the last are xyz 

I know about syntax like the following:

/abc\(xyz\)\@! 

but that only avoids matching abcxyz and not if there is anything in between, such as abc-xyz. Using

/abc.*\(xyz\)\@! 

also does not work because there are many positions later in the line where xyz is not matched.

(I should note that on the command line I would do something like grep abc <infile | grep -v xyz but I would like to do the above interactively in Vim.)

Answer 1

Your attempt was pretty close; you need to pull the .* that allows an arbitrary distance between the match and the asserted later non-match into the negative look-ahead:

/abc\(.*xyz\)\@! 

I guess this works because the non-match is attempted for all possible matches of .*, and only when all branches have been exhausted is the \@! declared as fulfilled.