[R-pkg-devel] Trouble with greek letter in figure title in R-devel

[Ulrike Groemping]

Dear package developers,

I am struggling with an error on R devel (all flavors) that I cannot 
reproduce with a freshly installed R-devel on my machine: Function 
halfnormal in package DoE.base places the greek letter alpha in the 
title of a figure. I changed the code to using plotmath about a month 
ago (on CRAN request), and everything seemed fine then. Now, however, 
R-devel produces an error message 
(https://www.r-project.org/nosvn/R.check/r-devel-windows-x86_64/DoE.base-00check.html):

Error in title(...) :
   conversion failure on 'Plot for rnorm.12., method = Lenth, α = 0.05' 
in 'mbcsToSbcs': for α (U+03B1)
Calls: halfnormal ... <Anonymous> -> plot -> plot.default -> localTitle 
-> title
Execution halted

CRAN threaten to archive the package because of that error - so I would 
really appreciate help on finding out what I should do (apart from nasty 
things like writing alpha instead of using the greek letter).

The code in function halfnormal that creates the title in question looks 
as follows:

   ## added August 1 5 2014, modified Oct 17 2023
   if (is.null(titel)){
      titel <- as.expression(bquote("Plot for "*.(xnam)*", "*alpha == 
.(alpha)))
      dots$main <- titel
   }

The list dots is later used in "do.call(plotfun, dots)".

Any recommendations?

Thanks and regards,
Ulrike