dlmread cannot read what dlmwrite wrote

[antoine-levitt]

On nightly,

using DelimitedFiles

a = [[(1,2),(3,4)]]
writedlm("test.txt",a)
readdlm("test.txt")

returns

1×4 Array{Any,2}:
 "(1,"  "2)"  "(3,"  "4)"

Maybe writedlm should refuse to write objects it cannot read back in a sensible way (ideally, readdlm(writedlm()) should be a no-op, but that might be too restrictive).