decode mutations from BTOP string in R (uses tidyverse)

btop.R

decode_btop <- function(btop)
{
	matches <- as.integer(str_extract_all(btop, "\\d+", simplify = T))
	matches <- if (str_starts(btop, "\\d", negate = T)) c(0, matches) else matches
	pos <- 0; n <- 0; m <- 0; muts <- list();
	for (ele in Filter(nchar, str_split(btop, "\\d+", simplify = T)))
	{
		pos <- pos + matches[n<-n+1]
		for (i in seq(1, nchar(ele), 2)) muts[[m<-m+1]] <- list(pos = pos<-pos+1, mut = substr(ele, i, i+1))
	}
	muts
}

not sure if it is possible to vectorize due to loop-dependency...