[Haskell-beginners] Unicode Fanatic — How to use?

John M. Dlugosz ngnr63q02 at sneakemail.com
Thu Mar 27 20:51:22 UTC 2014

I love using non-ASCII characters!  Even my name, Długosz, needs Latin-2.  My wife's name, 
涛, doesn't even use Latin characters.  I've inserted thousands of em and en dashes in 
Wikipedia and can easily type at least three kinds of blank space.

When I was in a college class on programming theory, we studied Backus’s FP System and I 
corresponded with John Backus to ask a question the prof couldn't handle, and he sent me 
the TeX definitions he used, so my homework really did match the appearance of the 
textbook.  But that's another story.  I managed to get my name in the Unicode 3 hardcopy book.

So, I relish the ability to use proper math symbols in Haskell.

Here is an example of what I've tried:

	{-# LANGUAGE UnicodeSyntax #-}

	import Prelude.Unicode

	f x y = x∨y

	result = f ∘ id

	-- problem = ¬ True

Is the UnicodeSyntax pragma a different mechanism than the modules?  Do I need to state 
both, or do they clash, or work together, or what?

Do I need to list all the individual modules (up to 12 of them) as needed (see 
http://hackage.haskell.org/package/base-unicode-symbols) or can they be brought in as one 
easy chunk, as the package itself is one thing?

The compiler does not like the ¬ symbol, with or without the pragma.
clearly shows it (the first one!) and it appears in the module source so presumably it 
didn't choke there.  I recall seeing that it is one of the "problematic" symbols but GHC 
has some extensions.

OTOH, I read that λ can’t be made to work, which is sad.  Maybe ⅄ (which is a symbol) can 
be used instead?

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