scheme parser = "read"

This is another article for my ongoing learnings with writing a scheme interpreter(hosted here). As I described in my previous post that I started with writing a formal EBNF grammar and a recursive descent parser for it.
When I came to implementing "read" function of scheme, then I realised that it essentially is the parser of scheme and list data structure is AST. Moreover when I write the formal grammar then the syntactical rules of the language are fixed at the time of parsing itself and its very difficult now to provide macros. Instead the parser or the "read" should just read *any* valid s-expression and "eval" only should derive any meaning from it.
So I've now changed my implementation and written a "read" that reads any valid s-expression and "eval" provides meaning to it.