[Haskell-beginners] infix and bind pseudonym

[Magnus Therning]

On Wed, Mar 4, 2009 at 1:20 PM, Daniel Fischer <daniel.is.fischer at web.de> wrote:
> Am Mittwoch, 4. März 2009 13:59 schrieb Magnus Therning:
>> Yes, there are certain function names that allow infix usage without
>> the back-ticks, the name 'chain' doesn't.  What those function names
>> are?  Roughly you can say that functions that they are functions that
>> look like binary operations, like + - ++ >>> etc.  I'm not sure I read
>> the pangauage spec correctly, but it looks like operators are made up
>> of the following characters !@#$%^&*+-./\|<=>?~ (IIRC ':' has a
>> special meaning in that it's allowed in "constructors", cf 1:2:[]).
>
> ':' is the symbol-equivalent of an upper case letter, so it's special only if
> it's the first symbol of an operator name, then the operator is a
> constructor. It can appear in any place but the first in ordinary operators.
> For example:
>        (:) :: a -> [a] -> [a]  -- first symbol is ':' => constructor
>        (:+) :: (RealFloat a) => a -> a -> Complex a    -- constructor
>        (/:/) :: a -> b -> b    -- ':' not first symbol => ordinary operator

Yes, that's what I meant, but you put it more nicely :-)

Is : really allowed in the middle of an operator like that?  (I can't
find it at all in the description of var-symbol on the last page in
http://www.cs.uu.nl/wiki/pub/FP/CourseLiterature/haskellsyntax-main.pdf
, hence my question.)

/M

-- 
Magnus Therning                        (OpenPGP: 0xAB4DFBA4)
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