I am trying to write a major mode in which all instances of a node in another matched node. For this, recursion is needed, and for that it is necessary to store a match in a variable:

Say I want to highlight all instances of (x) that are inside y in the following parse tree, where bolded means I want to match:

(x) in (q (y (x) (l (x) (l (x) (p))) (x))

"(y) @test
        @test . (_) @font-lock-variable-name-face"

"(y) @test
        (@test . (_) @font-lock-variable-name-face)"

"(y) @test
        (test . (_) @font-lock-variable-name-face)"

All of the above fail, which leads me to think that @test stores the text instead of the tree. In this case, how would I recursively match all instances of