[Rd] makepredictcall

Therneau, Terry M., Ph.D. therne@u @end|ng |rom m@yo@edu
Sat Aug 13 13:20:28 CEST 2022

I'm trying to better understand makepredictcall.  The method for ns() starts with the 
following very cryptic comment and line of code:
     ## check must work correctly when call is a symbol, both for quote(ns) and quote(t1):
     if(as.character(call)[1L] == "ns" || (is.call(call) && identical(eval(call[[1L]]), 
ns))) {

The phrase "t1" appears no where else in the src/library/splines/R, and there is nothing 
relevant in stats/R either  (t1 gets used as a temp variable in 2 subfunctions).
So, what is the purpose of this line of code?

I can see that if a user typed   zed <- ns, then used 'zed' in their call, that the right 
hand clause would then be true but not the left; but why worry about that case?

Terry T.

  PS (The help file isn't very helpful for creating such a method BTW.  It tells why you 
should make one, and what happens if you get it right, but nothing on how.)

Terry M Therneau, PhD
Department of Quantitative Health Sciences
Mayo Clinic
therneau using mayo.edu

"TERR-ree THUR-noh"

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