In
https://ask.wireshark.org/question/5530/what-is-the-expected-valueformat-for-display-filter-in/
somebody asks why
tcp.stream in {1,8,12,18}
doesn't work.
The answer is "you have to separate them with spaces".
Is there some reason why they *must* be separated by spaces, rather than by allowing, for example, commas or semicolons?
One reason that comes to mind, for floating-point numbers, is that, if we use the locale's decimal separator in filter expressions, a comma might be the decimal separator, i.e.
float.field in {1 <one and a half> 2}
would be
float.field in {1 1.5 2}
in some locales but
float.field in {1 1,5 2}
so, while
float.field in {1,1.5,2}
would work in locales with . as a decimal separator,
float.field in {1,1,5,2}
wouldn't work in locales with , as a decimal separator.
Is that the reason?