It is currently unknown if this will produce a performance increase, but unless it has a significant performance penalty we are going to go forward with this change because it makes it more explicit which values need to be read deeply from other elements (therefore needing to be in the context) vs values that can be bound to the exit matcher since they are only used within the confines of the current element.
I suspect we will get a performance boost since it will be reducing the nodes that need to be walked in the context but maintaining bracket depth count over the entire document instead of only inside elements that need balanced brackets could cost us.
The documentation currently states that the body for these cannot span more than three lines but that is not the behavior I am seeing from emacs in practice. Waiting on a mailing list response to tell me if this is a documentation error or a parser error.
