To implement implicit parenthesis is possible to add a parameter to macro definitions to tell the reader how many parameters the function takes, so that it can add an opening brace when it sees a macro name and it closes it after n arguments. I've done so in a toy lisp interpreter I'm writing, but after a while i removed that feature because i didn't like implicit parehthesis, when manipulating forms within macros you have to remember about implicit parenthesis and this makes macros less natural.
