On 12-01-07 2:44 PM, cbe...@tajo.ucsd.edu wrote:
Duncan Murdoch<murdoch.dun...@gmail.com> writes:
On 12-01-06 10:21 PM, Rolf Turner wrote:
On 07/01/12 15:51, R. Michael Weylandt<michael.weyla...@gmail.com> wrote:
I imagine the answer will involve lazy evaluation and require you use force()
but I'm not quite qualified to pronounce and not at a computer to test.
I think you've got it; I tried
junk<- vector("list",4)
for(i in 1:4) {
junk[[i]]<- eval(bquote(function(x){42 + .(force(i))*x}))
}
and got the result that I wanted. Still don't completely understand, but
it at least makes vague sense and makes me a bit more comfy.
I'm not so sure. The index in a for loop isn't supposed to be a
promise. To me, it looks like a bug, maybe in bquote()...
Duncan,
IIUC, the promise is created by bquote().
No, as Gabor said, there was no promise there. Luke Tierney tracked it
down to a bug, which is now fixed in R-patched and R-devel (as of
revision r58074).
Duncan Murdoch
Replacing
eval(e[[2L]], where)
by
{
e[[1L]]<- as.name("force")
eval(e)
eval(e[[2L]], where)
}
seems to handle this case without breaking example(bquote).
HTH,
Chuck
Duncan Murdoch
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