I don’t understand this page: https://orgmode.org/worg/dev/org-syntax.html#Emphasis_Markers

In particular, the BORDER BODY BORDER part.  Note that this is the CONTENT which is already between MARKERS.

What I *think* I want is the ability to effectively create what I’ll call “macros”.  I’d like to be able to separate out things like file paths, code samples (both in line and block), keywords, environment variables, code variables, etc.  So, as I write, I would do (as a total pretend example) [var]foo_dog[var] to denote foo_dog as a code variable.  I’m wondering if that isn’t what the “BORDER” character is.  From the way the section is written, I would assume the leading border character must be the same as the trailing border character so I could do ~vfoo_docv~  where the “v” would be the border character?

OR… perhaps what this is trying to tell me is the first character after the leading marker and the last character before the trailing marker must not be whitespace characters since that is how it appears from all of the examples.

My logic is if I take the time to separate out all of the elements as I write the document, then I can later decide to format, for example, code snippets the same as variables.  It would also help me to be more consistent while I write because I’m (currently) having to remember “Ok… how did I format variables?  Was that ‘code' or ‘italics'? … Hmm…”

If I’ve misunderstood this page, then perhaps to save a follow up email, can someone tell me if I can create “macros” within Org mode to do what I mentioned OR tell me that I really don’t want to go down that path for some reason.

Thank you for your help,
Perry