TITLE(call @@ Function Calls)
USAGE(
call(name, DOTS)
BLANK
is.call(expr)
as.call(expr)
)
ALIAS(call)
ALIAS(is.call)
ALIAS(as.call)
VALUE(
An unevaluated function call, that is, an unevaluated expression
which consists of the named function applied to the given arguments
(LANG(name) must be a quoted string which gives
the name of a function to be called).
PARA
LANG(is.call) is used to determine whether LANG(expr) is a call.
We don't differentiate between expressions and function calls.
So LANG(is.call) is the same as LANG(is.expression).
PARA
It is not possible to coerce objects to mode call
(objects either are calls or they are not calls).
LANG(as.call) returns its argument if it is a call and
otherwise terminated with an error message.
)
SEEALSO(
LANG(LINK(expression)), LANG(LINK(function)).
)
EXAMPLES(
is.call(call) #-> FALSE: Functions are NOT calls
BLANK
# set up a function call to round with argument 10.5
cl <- call("round",10.5)
cl
# such a call can also be evaluated.
eval(cl)# [1] 10
)
