getStartMark should return a Mark instance

and getLine should return an int https://bitbucket.org/snakeyaml/snakeyaml/src/180363cfff5c9334bdd21b0d38145fa56ceed91c/src/main/java/org/yaml/snakeyaml/error/Mark.java#lines-121:123

I want the int line number

hmm https://stackoverflow.com/questions/60989912/dealing-with-java-optionalt-in-clojure

maybe this will help https://github.com/fr33m0nk/optional

I don't yet see where things are defined optional

an optional has the .orElse method to get the value out, or a default value if the optional doesn't have a value

the way to do this in clojure would probably be:

(some-> (.getStartMark event) (.orElse nil) (.getLine))

nice!