gtk:text-iter-toggles-tag (iter tag)

iter -- a gtk:text-iter instance
tag -- a gtk:text-tag object, or nil

The boolean whether tag is toggled on or off at the iterator.

Tells you whether a range with tag applied to it begins or ends at the iterator. This is equivalent to

(or (gtk:text-iter-starts-tag iter tag)
    (gtk:text-iter-ends-tag iter tag))