call                  package:base                  R Documentation

_F_u_n_c_t_i_o_n _C_a_l_l_s

_D_e_s_c_r_i_p_t_i_o_n:

     Create or test for objects of mode `"call"'.

_U_s_a_g_e:

     call(name, ...)
     is.call(x)
     as.call(x)

_A_r_g_u_m_e_n_t_s:

    name: a character string naming the function to be called.

       x: an arbitrary R object.

_V_a_l_u_e:

     `call' returns an unevaluated function call, that is, an
     unevaluated expression which consists of the named function
     applied to the given arguments (`name' must be a quoted string
     which gives the name of a function to be called).

     `is.call' is used to determine whether `x' is a call (i.e., of
     mode `"call"').

     It is not possible to coerce objects to mode call (objects either
     are calls or they are not calls).  `as.call' returns its argument
     if it is a call and otherwise terminates with an error message.

_S_e_e _A_l_s_o:

     `do.call' for calling a function by name and argument list;
     `Recall' for recursive calling of functions; further
     `is.language', `expression', `function'.

_E_x_a_m_p_l_e_s:

     is.call(call) #-> FALSE: Functions are NOT calls

     # set up a function call to round with argument 10.5
     cl <- call("round", 10.5)
     is.call(cl)# TRUE
     cl
     # such a call can also be evaluated.
     eval(cl)# [1] 10

