[R] A question about using delayedAssign

[William Dunlap]

Change
   delayedAssign("x", msg)
to
   delayedAssign("x", { cat("Assigning 'msg' to 'x' now\n") ; msg })
and you will see the message when the delayed assignment is triggered.
You could add print(sys.calls()) to that to see the call stack if it isn't
obvious.

> msg <- "old"
> delayedAssign("x", { cat("Assigning 'msg' to 'x' now\n") ; print(sys.calls()) ; msg })
> f <- function(p) paste(x, p)
> f("qwerty")
Assigning 'msg' to 'x' now
[[1]]
f("qwerty")

[[2]]
paste(x, p)

[[3]]
print(sys.calls())

[1] "old qwerty"
> x
[1] "old"


Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> Of Gang Peng
> Sent: Wednesday, August 14, 2013 6:12 PM
> To: r-help at r-project.org
> Subject: [R] A question about using delayedAssign
> 
> I run the examples in delayedAssign:
> 
> msg <- "old"
> delayedAssign("x", msg)
> msg <- "new!"
> x
> 
> If I run these four commands together, x is "new". If I run the first two
> commands first and then run the last two commands, x is "old".
> 
> I just cannot figure out why.
> 
> Thanks.
> Gang
> 
> 	[[alternative HTML version deleted]]
> 
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