$ perl -MCSV -e'dcsv (in => [["a","b","c"],[1,"=2+3",4],[6,"",7,"=8+9"]], quote_empty => 1)'
a,b,c
1,=2+3,4
6,"",7,=8+9
1

$ perl -MCSV -e'dcsv (in => [["a","b","c"],[1,"=2+3",4],[6,"",7,"=8+9"]], quote_empty => 1, formula => "none")'
a,b,c
1,=2+3,4
6,"",7,=8+9
1

$ perl -MCSV -e'dcsv (in => [["a","b","c"],[1,"=2+3",4],[6,"",7,"=8+9"]], quote_empty => 1, formula => "die")'
a,b,c
Formulas are forbidden
Exit 255

$ perl -MCSV -e'dcsv (in => [["a","b","c"],[1,"=2+3",4],[6,"",7,"=8+9"]], quote_empty => 1, formula => "croak")'
a,b,c
Formulas are forbidden
Exit 255

$ perl -MCSV -e'dcsv (in => [["a","b","c"],[1,"=2+3",4],[6,"",7,"=8+9"]], quote_empty => 1, formula => "diag")'
a,b,c
Field 1 contains formula '=2+3'
1,=2+3,4
Field 3 contains formula '=8+9'
6,"",7,=8+9
1

$ perl -MCSV -e'dcsv (in => [["a","b","c"],[1,"=2+3",4],[6,"",7,"=8+9"]], quote_empty => 1, formula => "empty")'
a,b,c
1,"",4
6,"",7,""
1

$ perl -MCSV -e'dcsv (in => [["a","b","c"],[1,"=2+3",4],[6,"",7,"=8+9"]], quote_empty => 1, formula => "undef")'
a,b,c
1,,4
6,"",7,
1