On 09/14/2018 08:33 PM, Jeremie Juste wrote:
Hello,
I'm wondering it is possible and if yes would it be desirable to modify
the return value of functions during evaluation.
I supposed this would be very useful during debugging
myfun <- function(x) {res <- x+3 ; browser() ; res}
let say I run the following function myfun(3) and drop in the browser. I then
happened to notice that I should
multiply <x> by 3 instead of adding. I was thinking to do return(x*3)
but the return value is still 6.
myfun(3)
Called from: myfun(3)
Browse[1]>
debug at #1: res
Browse[2]> return(3*3)
[1] 6
Don't use return(). Change the value of "res" and then "continue".
Browse[1]> res <- x*3
Browse[1]> c
You will get the value 9 returned by "myfun(3)". (God how I hate this
stupid egocentric sounding "mythis" and "mythat" syntax that Micro$oft
has inflicted upon the world. But never mind.)
I am however very sure that your proposed approach is Not A Good Idea.
If you want an interactive structure for your function, make it
interactive. In a well thought out and well organised manner.
cheers,
Rolf Turner
--
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276
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