>Using Lisp to read and write a configuration file means you don't need to worry about lexing and parsing either.

That was the point I was trying to make, apparently unsuccessfully.

>If you don't use Lisp, or if you don't use S-expressions, you will need to lex and parse the configuration file just to read it, compiler or no compiler.

Any time you build a lexer and a parser, you are building a compiler (I'm using a broader meaning of compiler - not necessarily one that outputs bytecode). There are many XML-to-HTML compilers, for example.

Lisp macros compile DSL's to Lisp. That's why a Lisp programmer rarely needs to think about lexing and parsing. It is automatic and implied if you address the problem in the right way. It's also why the concepts of data and programs are necessarily conflated in Lisp.