Commented by default

Dear All,

is it somehow possible (ie via macros) to have a line in a scheme source code file being a comment line by default and only when a certain symbol or group of symbols is starting a line it is an uncommented / evaluated line? Basically, the reverse of a normal source file where I need to introduce a comment line. I would imagine a header line setting up this "comment"-mode, and below this every line becomes a comment unless explicitly uncommented.

Thanks for your help and insights

Christian