read.FCS fails if transformation=custom keyword is present but flowCore_$PnRmax isn't present for all channels

[zbjornson]

flowCore/R/IO.R

Lines 1028 to 1031 in 4c4186d

	if( "transformation" %in% names(x) && x[["transformation"]] == "custom"){
	range_str <- sapply(seq_len(nrpar),function(k){
	x[[sprintf("flowCore_$P%sRmax", k)]]
	})

The above assumes that flowCore_$P%sRmax will be present for all parameters, but that's not necessarily the case. Many tools pass-through keywords from original FCS files while adding one or more new parameters. Could this be changed to fall back to $PnR?

[SamGG]

Hi Zach,
I dislike flowCore transformation being encoded/annotated in FCS files. This creates problem as you encounter. I have already raised the same/similar issue (Why the flowCore_$P parameters are written to disk instead of using the standard $PR? #201). Does setting tranformation=FALSE pose a problem to your code? I only rely on that.
Best.