[R-pkg-devel] [FORGED] obscure syntax error

[Rolf Turner]

On 22/03/19 11:18 PM, Jim Lemon wrote:

> Hi,
> I have been attempting to check a new version of the prettyR package,
> and have struck a difficult problem. The check fails at the
> installation, and when I track the error, it is "Unexpected end of
> input" in the xtab function. I have tried a number of things as I
> thought that it was a non-printing character (I have had that happen
> before). I can paste the entire function into an R session and there
> is no error. Has anyone struck an error like this before?
> 
> xtab<-function(formula,data,varnames=NULL,or=TRUE,chisq=FALSE,phi=FALSE,
>   html=FALSE,bgcol="lightgray") {
> 
>   if(missing(formula))
>    stop("Usage: xtab(formula,data,varnames=NULL,or=TRUE,chisq=FALSE,phi=FALSE\n")
>   ft<-as.character(attr(terms(formula),"variables")[-1])
>   nft<-length(ft)
>   if(nft>2) {
>    xt<-list()
>    by.factor<-as.factor(data[[ft[nft]]])
>    factor.levels<-levels(by.factor)
>    factor.labels<-attr(data[,ft[nft]],"value.labels")
>    if(!is.null(names(factor.labels))) factor.labels<-names(factor.levels)
>    if(is.null(factor.labels)) factor.labels<-factor.levels
>    nlevels<-length(factor.levels)
>    for(i in 1:nlevels) {
>     currentdata<-subset(data,by.factor==factor.levels[i])
>     for(j in 1:dim(currentdata)[2])
>      attr(currentdata[,j],"value.labels")<-attr(data[,j],"value.labels")
>     currentcount<-length(currentdata[[nft]])
>     totalcount<-length(data[[nft]])
>     cat("\nCount for",ft[nft],"=",factor.labels[i],"is",currentcount,
>      "(",round(100*currentcount/totalcount,1),"%)\n\n")
>     rightside<-ifelse(nft>3,paste(ft[2:(nft-1)],sep="",collapse="+"),ft[2])
>     next.formula<-as.formula(paste(ft[1],rightside,sep="-",collapse=""))
>     xt[[i]]<-xtab(next.formula,data=currentdata,varnames=varnames,chisq=chisq,
>      phi=phi,html=html,bgcol=bgcol)
>    }
>   }
>   else {
>    if(missing(data)) xt<-calculate.xtab(get(ft[1]),get(ft[2]),varnames=varnames)
>    else xt<-calculate.xtab(data[,ft[1]],data[,ft[2]],varnames=varnames)
>   }
>   attr(xt,"class")<-"xtab"
>   return(xt)
> }
>   Thanks for any pointers.

I believe I have encountered phenomena like this where the error was 
actually in the *"previous"* function in the sequence of package 
functions stored in the *.rdb or *.rdx files in the "R" directory of the 
package.

To track down where the error is actually occurring I cd to the R
directory of the *source* package, start R, and do something like:

phials <- list.files(pattern=".R$")
for(phial in phials) {
     cat(phial,"\n")
     source(phial)
}

That should allow you to spot the loony pretty quickly.

HTH

cheers,

Rolf

-- 
Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276