It turns out that there is at least a (partial) solution to my
quasiquote problem. Template Haskell's reify function can be used to
find an operator's fixity, although it seems not for all cases.
However, for the purposes of this discussion, suppose I can write a
function
userFixity :: String - Q
On Sun, Nov 23, 2008 at 8:23 AM, John A. De Goes [EMAIL PROTECTED] wrote:
Though many see it as losing information, I agree wholeheartedly with your
proposal to change the AST.
It's better to have an AST that conveys less information, but truthfully,
than to have an AST that purports to
On Mon, Nov 24, 2008 at 12:39 AM, Niklas Broberg
[EMAIL PROTECTED] wrote:
I want this information to be used somehow when creating the Template
Haskell AST, so that the operators used have the correct fixities. If
I use HSE for parsing Haskell expressions, then I want it to tell me
where it
No, I believe it wouldn't. The left-biased tree cannot distinguish
where parentheses have been used from where HSE inserted its own left
fixities. For instance, if we have the expressions
xs ++ ys ++ zs
(xs ++ ys) ++ zs
Then HSE will return something like (I'm using strings for the
Of course, this would require a change to Template Haskell, so a
second-best solution would be to forbid unparenthesised expressions in
my quasiquoter. Then, parsing can proceed correctly without knowing
the fixities. This would be easiest to do if haskell-src-exts changed
its AST in a
It seems to me that fixity information behaves more like semantics
than like syntax. For instance, fixities may be imported, and obey
namespacing rules. Knowing and correctly handling these rules seems
beyond the scope of a mere parser: I would hope that a single Haskell
file could be parsed
