`S7::method` does not accept an S3 generic while the doc suggest it should.

[lgautier]

In R, with S7 v0.2.0:

> isS3stdGeneric(print)
print 
 TRUE 
> S7::method(print)
Error: `generic` must be a <S7_generic>, not a <closure>

The doc says:

Usage:

     method(generic, class = NULL, object = NULL)
     
Arguments:

 generic: A generic function, i.e. an S7 generic, an external generic,
          an S3 generic, or an S4 generic.

[kevinushey]

+1. It's also awkward that one can define an S3 method in this way:

> s7mean <- S7::new_class("s7mean")
> S7::method(mean, s7mean) <- function(x, ...) {
+    print("This is my S7 method")
+ }

And yet you cannot retrieve it using the same syntax:

> S7::method(mean, s7mean)
  Error: `generic` must be a <S7_generic>, not a <closure>

[mmaechler]

method<- is defined in S7 and in some sense is a major "feature" of S7, using an S- and R- like syntax to change / create an extension / extra part of an object (like, e.g., names(obj) <- value).

I've edited my original comment now, which contained considerable nonsense, I'm sorry.

We do have method in S7 (and not in base, I was confusing it with methods()),
and indeed, @kevinushey 's example to support S7 methods for base / S3 generics does make a lot of sense, unless we'd want to forbid the creation of such methods.