[S] On defining functions within functions: a function might be invisible to itself

[Jens Oehlschlaegel <oehl@Psyres-Stuttgart.DE>]

# look at a function which does some (here nonsense) recalling
test <- function(x=1){
        if (x==1) test(2)
        else "OldTest"
}

> test()
[1] "OldTest"
# looks like a function which works, as long as you not rename it


# now define such a function within another function
test2 <- function(){
        test <- function(x=1){
                if (x==1) test(2)
                else "NewTest"
        }
        test()
}

> test2()
[1] "OldTest"
# silently returns "OldTest" instead of "NewTest"


# a good reason to use Recall()
test2 <- function(){
        test <- function(x=1){
                if (x==1) Recall(2)
                else "NewTest"
        }
        test()
}

> test2()
[1] "NewTest"

# Hats off to the programmer !

Best regards


--
Jens Oehlschlaegel-Akiyoshi
Psychologist/Statistician

CURRENT ADDRESS (until 12/98) | PERMANENT VIRTUAL ADDRESS
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(general disclaimer)


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