expressive C++17 in Julia

expressive.jl

(length(ARGS) < 4) && (println("error, insufficient arguments"); exit(1))

infile, column, replace, outfile = ARGS

function replace_column(idx)
  (idx == 0) && (println("column name doesn’t exist in the input file"); exit(1))
  mtx2 = copy(mtx)
  mtx2[2:end,idx] = collect(Iterators.repeated(replace,size(mtx,1) - 1))
  mtx2
end

try
  global mtx = readcsv(infile)
catch
  println("file missing")
  exit(1)
end

length(mtx) == 0 && (println("input file missing"); exit(1))
size(mtx, 1) == 1 && writecsv(outfile, mtx)

mtx[1,:]                    |> 
  a -> findfirst(a, column) |> 
  replace_column            |>
  m -> writecsv(outfile, m)