Is there a document that describes these? I've seen them mentioned before as one of the superpowers of Sam, but I've never seen a clear explanation of them for someone who isn't already a Sam user. I have no real intention of ever using or trying Sam as my daily text editor for a handful of reasons, but I am interested in new paradigms and tools for working with code.
I am not really an expert but my understanding is that they are called that because you can use them to define the structure of a match. in most regular expression engines the structure is defined as a line of text or the whole document and the expression only matches the contents. This is why they do so well with multi line records you just need to define a structure expression that matches your, well.. structure.
I never did learn sam all that well, I mainly used it as a non interactive sed replacement. however I just learned that apparently the vis project uses structural expressions. I might try it. Mainly because at least then my fingers sort of know what to do.
