Re: [Rd] model.matrix.default chokes on backquote (PR#7202)

From: Peter Dalgaard <p.dalgaard_at_biostat.ku.dk>
Date: Mon 30 Aug 2004 - 16:34:35 EST

"Gabor Grothendieck" <ggrothendieck@myway.com> writes:

> > y ~ `offset(foo)` + offset(foo)
> >
> > I.e. perhaps the real issue is that names(data) gets generated without
> > backquotes.
> >
> > Anyways, this is a real can of worms and I'm not sure we're not too
> > close to 2.0.0 to start tampering with it...
>
> How about a partial fix that does not address pathological
> cases where the variable names themselves have embedded
> backquotes but does address the common cases such as:
>
> y <- ts(1:10); x1 <- y^2; x2 <- y^4
> lm(`lag(y)` ~ ., cbind(lag(y), x1, diff(x2)) )
>
> without having to resort to:
>
> lm(lag.y ~ ., cbind(lag.y = lag(y), x1, diff(x2)) )

Hmmm... Point taken, but I'm not happy about the fact that the internals seem unable to discern `lag(y)` (the name) and lag(y) (the call). One might consider "backtickifying" the names of the data matrix instead:

> bq <- function(x)sapply(x,

          function(nm)deparse(as.name(nm),backtick=TRUE))
> bq(c("a","a(b)"))

       a     a(b)
     "a" "`a(b)`"


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907

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