[Rd] surprising behavior of match.arg() (PR#872)
Peter Dalgaard BSA
p.dalgaard@biostat.ku.dk
08 Mar 2001 22:51:50 +0100
Peter Dalgaard BSA <p.dalgaard@biostat.ku.dk> writes:
> Setzer.Woodrow@epamail.epa.gov writes:
>
> > If a function needs to be passed as an argument to another function,
> > default arguments to the function being passed are lost. Consider this
> > example:
>
> Interesting...
>
> Apparently, sys.function() is still a promise after the function has
> been called (and the promise obviously forced).
> Minimal example of same effect:
>
> > f<-function()sys.function()
> > f()
> function()sys.function()
> > g<-delay(f)
> > g()
> <promise: 0x8b248b4>
> > g<-g
> > g()
> function()sys.function()
Fixed for 1.3.0.
(Not sure I'm happy with this yet. R_sysfunction works on the *call*
of the function, and if the head of the call is a LANGSXP - as in
h(x)(y) - it gets evaluated a second time, and I don't think that
is guaranteed to give the same function as the first time! We really
ought to keep a pointer to the function itself around too.)
-p
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._