Martin Maechler wrote:
> but notably not mainly by the above. I'd consider the backtick
> operator as -- very nice -- syntactic sugar for
> assign() and get().
>
> And, for "normal" identifiers,
>
> foo <- 1
> `foo` <- 1
> assign("foo", 1)
>
"foo" <- 1
# same effect as above
> and
> foo
> `foo`
> get("foo")
>
"foo"
# not 1?
(that is to say, i find this a tiny little bit incoherent, but perhaps
useful for assignments, as " is easier to get from my keyboard than `)
> are each three-fold equivalent. If a user does not *know* about
> keywords/reserved words, (s)he can get a bit confused by
> how e.g. break or `break` e.g. are handled:
> Recall that Joe Average User does not know about assign, get,
> `..` etc, but does know about ls() and typing an object name:
> If he does ls(), sees "break" (which stems from previous
> assign("break", 3) or `break` <- 3)
> and then types
> > break
> or
> > str(break)
>
btw. i find the following sequence of error messages a tiny little bit
confusing:
break(1)
# Error: no loop to break from, jumping to top level
"break" = function(arg) arg
break(1)
# Error in break : argument "arg" is missing, with no default
"break" = function(arg=1) arg
break(1)
# Error: attempt to apply non-function
"if" = function(arg) arg
if(1)
# keeps waiting for more input
if(1) 2
# Error in if (1) 2 : unused argument(s) (2)
vQ
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