Okay, I know about using the hyphen to connect certain words, but I'm not so aware of the one to connect thoughts. Here are two examples of what I'm talking about. This comes from the third book of the Iron Duid Chronicles so be aware of any minor spoilers;
That blow had clearly been intended to take my head off or punch a hole through my chest-or something equally fatal.
Sure, the beard was being controlled magically, but that magic was targeting the hair, not me, and apart from being completely gross, such hair could constrict my windpipe every bit as effectively as a length of rope-and there were twelve such lengths reaching for me now.
Is this the two seperate thoughts you speak of? If I had written this, I would have used commas, so would I have technicaly written it incorrectly? Or is writing that way a matter of personal taste?