$ cat formula.csv
a,b,c
1,=2+3,4
6,,7,=8+9,

##</code><code>##

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

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

$ perl -MCSV -e'dcsv (in => "formula.csv", formula => "die")'
Formulas are forbidden

$ perl -MCSV -e'dcsv (in => "formula.csv", formula => "croak")'
Formulas are forbidden

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

$ perl -MCSV -e'dcsv (in => "formula.csv", formula => "empty")'
[
    [   'a',
        'b',
        'c'
        ],
    [   '1',
        '',
        '4'
        ],
    [   '6',
        '',
        '7',
        '',
        ''
        ]
    ]

$ perl -MCSV -e'dcsv (in => "formula.csv", formula => "undef")'
[
    [   'a',
        'b',
        'c'
        ],
    [   '1',
        undef,
        '4'
        ],
    [   '6',
        '',
        '7',
        undef,
        ''
        ]
    ]

##</code><code>##

$ 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

##</code><code>##

$ cat formula.csv
a,b,c
1,=2+3,4
6,,7,=8+9,

$ perl -MCSV -e'$_ = dcsv (in => "formula.csv", bom => 1, formula => "diag")'
Field 2 (column: 'b') in record 1 contains formula '=2+3'
Field 4 in record 2 contains formula '=8+9'