foo <- function(arg_1, arg_2, ...) expression
> foo = function(data, data.frame, graph=TRUE, limit=20) {
...
+ }
> toto = foo(d,df,TRUE,20)
> toto = foo(d,df,graph=TRUE,limit=20)
> toto = foo(data=d,limit=20,graph=TRUE,data.frame=df)
> toto = foo(d,df)
> toto = foo(d,df,limit=10)