7.2.1.1 FWEB macros with variable arguments

An important extension to the ANSI-C syntax is to allow macros with variable (optional) arguments. FWEB macros with a variable number of arguments are indicated by an ellipsis, as in

@m VAR(x,y,z,...) text

The tokens ‘#0’ (number of variable arguments), ‘#n’ (value of the nth optional argument), and ‘#.’ (comma-delimited list of the optional arguments) are useful in this context.