#### Which functions in R  are  .Primitive()  / which should be ?
#### ------------------------------------------------------------
#### M.Maechler, May, 1998.
####
#### ==> ../doc/manual/primitive-funs.tex
####     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

bpos <- match("package:base",search())
nn <- ls(pos=bpos)
length(nn) # 844  [R 0.62.0, March 25, 1998]

is.primitive <- function (obj) is.function(obj) && is.null(args(obj))

Primf <- nn[sapply(nn, function(N) is.primitive(get(N, pos=bpos)))]
length(Primf) ## 195  R 0.62.0, March 25, 1998
              ## 132  R 0.62.2+
Real.primitives <-
 list(
      specials = c("{", "(", "if", "for", "while", "repeat", "break", "next",
        "return", "function",
        "on.exit" ## on.exit(expression, add=F) has two arguments in S-plus !
        ),
      language = c( "$", "$<-", "<-", "<<-", "[", "[<-", "[[", "[[<-"),
      arith = c("%%", "%*%", "%/%","*", "+", "-", "/", "^"),
      logic = c("!",  "&", "&&",  "|", "||",
                "<", "<=", "==", ">", ">=", "!="),
      arithF =
      c("sign", "abs",
        "floor", "ceiling",
        "sqrt",
        "exp",  ## NOT: "log",
        "cos",    "sin",  "tan",
        "acos",  "asin", "atan", ## Not:  atan2
        "cosh",  "sinh", "tanh",
        "acosh","asinh","atanh",
        "cumsum","cumprod",
        "cummax", "cummin"
        ),
      arithC = c("Arg", "Conj", "Im", "Mod", "Re"),

      programming =
      c("nargs", "missing", # actually args(.) could be as formal(.)
        "interactive",
        ".Internal",
        ".C", ".Fortran", "symbol.C", "symbol.For",
        "globalenv", "pos.to.env", "unclass",

        ##maybe ? "gc", "gcinfo",
        ##
        "debug", "undebug", "trace", "untrace",
        "browser",  "proc.time", #"traceback",
        ),

      language2= c(":", "~", "c", "list", "unlist",
        ".Alias",
        "call", "as.call", "expression", "substitute",
        "UseMethod", ## ? really ?
        "invisible",
        ),

      language3=
      c("environment<-",
        "length",	"length<-",
        "class",  	"class<-",
        ## "attr", not anymore [Summer '98]
                  	"attr<-",
        "attributes", 	"attributes<-",
        "dim",    	"dim<-",
        "dimnames", 	"dimnames<-",
## MM:  "comment", "comment<-",
## New data.frame code
##         "levels", "levels<-",
##         "codes",  "codes<-",
##         "[.data.frame",  "[<-.data.frame",
##         "[[.data.frame", "[[<-.data.frame"
        ),
      )
real.primitives <- unlist(Real.primitives)
##names(real.primitives) <- rep("",length(real.primitives))

!any(duplicated(real.primitives)) # TRUE
all(real.primitives %in% Primf)   # TRUE

"%w/o%" <- function(a,b)  a[! a %in% b]  ## a without b

prim.f <- Primf %w/o% real.primitives
## see below: contains the is.xxxx(.) funtions
length(prim.f) == length(Primf) - length(real.primitives)# TRUE

ncpf <- nchar(prim.f)
table(ncpf)
prim.f[ncpf <= 6]#  only is.na, is.nan

( prim.isf <- prim.f[p.isis <- substr(prim.f,1,2) == "is"] )

length(prim.f2 <- prim.f[! p.isis]) # down to 87   [R 0.62.0, March 25, 1998]
                                        # 61  [March 27]
                                        # 43  [April 17];  38 [April 22]
##-> 0  [May 1, 1998]

prim.f2 # character(0) --- none left! --

for(n in prim.f2)
  cat(n," <- function(*) .Internal(",n,"(*))\n", sep="")