GedcomxDate to edtf converter.
Install a rust compiler (with rustup):
curl https://sh.rustup.rs -sSf | sh
And build
cargo build --release
require './gedcomx2edtf'
puts Gedcomx2edtf.convert("+1988-03-29T03:19Z") # 1988-03-29T03:19-00:00
puts Gedcomx2edtf.convert("A+2003/+2003-05") # 2003~/2003-05~
puts Gedcomx2edtf.convert("/+1789") # [..,1789]
puts Gedcomx2edtf.convert("-0001") # -2