Would it be possible to determine the CSV delimiter based on the first line of the file?

I have a usecase where I store floats using a comma , as a decimal separator, which conflicts with the syntax highlighter.

Eg. the file

foo;bar;baz
1,2;1,7;2,7
1,5;8,5;-5,5

Renders as follows

As the header only contains one of the four accepted delimiters ;, would it not be safe to assume that any other character is not the delimiter?