What characters are permitted for Haskell operators?
haskell, operators, syntax
Solution
What I was looking for was the complete list of characters. Based on the other answers, the full list is;
Unicode Punctuation:
- http://www.fileformat.info/info/unicode/category/Pc/list.htm
- http://www.fileformat.info/info/unicode/category/Pd/list.htm
- http://www.fileformat.info/info/unicode/category/Pe/list.htm
- http://www.fileformat.info/info/unicode/category/Pf/list.htm
- http://www.fileformat.info/info/unicode/category/Pi/list.htm
- http://www.fileformat.info/info/unicode/category/Po/list.htm
- http://www.fileformat.info/info/unicode/category/Ps/list.htm
Unicode Symbols:
- http://www.fileformat.info/info/unicode/category/Sc/list.htm
- http://www.fileformat.info/info/unicode/category/Sk/list.htm
- http://www.fileformat.info/info/unicode/category/Sm/list.htm
- http://www.fileformat.info/info/unicode/category/So/list.htm
But excluding the following characters with special meaning in Haskell:
(),;[]`{}_:"'
A `:` is only permitted as the first character of the operator, and denotes a constructor (see An operator symbol starting with a colon is a constructor).
Problem
Is there a complete list of allowed characters somewhere, or a rule that determines what can be used in an identifier vs an operator?