FWIW, my first static blogging system (circa 2003) did almost exactly the same thing you are doing (except that I used `[]` for lists, not `{}`). IIRC, it was maybe 5-6 macros+functions (and some readtable magic) to turn every `[foo ...]` into `<foo> ... </foo>`, with support for attributes using `:name=value` syntax and a list of exceptions for non-closing tags such as `<br>`, etc.

I redid something like that recently, in C, and it turned out to be unreasonably larger to write than in Clisp.

TBH, these days it's better to simply stick to markdown, because the tooling is much better (previews as you type, tools to automatically generate the html, inline HTML for what markdown won't do, etc).