Representing missing ranges

[LiNk-NY]

Given a character vector, how do we represent missing ranges?
This is an ugly hack but it preserves the length of the original input.
But I would not expect to get much mileage out of it.

suppressPackageStartupMessages(library(GenomicRanges))
cranges <- c("chr1:29553-30267", "chr1:36080-36081", "chr1:65418-69055", 
    "chr1:120931-133723", NA)
cranges[is.na(cranges)] <- "NA_character_:0"
as(cranges, "GRanges")
#> GRanges object with 5 ranges and 0 metadata columns:
#>            seqnames        ranges strand
#>               <Rle>     <IRanges>  <Rle>
#>   [1]          chr1   29553-30267      *
#>   [2]          chr1   36080-36081      *
#>   [3]          chr1   65418-69055      *
#>   [4]          chr1 120931-133723      *
#>   [5] NA_character_             0      *
#>   -------
#>   seqinfo: 2 sequences from an unspecified genome; no seqlengths

^{Created on 2022-05-20 by the reprex package (v2.0.1)}