Fractional/negative fixity?
Claus Reinke
claus.reinke at talk21.com
Tue Nov 7 21:09:59 EST 2006
by all means, lets have warm fuzzy precedence declarations
infix(nearly right) (exp (2*i*pi) + 1) :-)
infix(mostly left) (((\x->cos x + i*(sin x)) (2*pi)) + 1) (-:
who says that all the fun has to start in the type system?-)
we would probably need to refer to hyperreals, in order to
introduce infinitesimal differences between real precedence levels?
oh, and let us not forget the early Basic's contribution to language
design: renum (who could ever to without it!-)
ah well, to justify the use of bandwith (and because you should
never let your design decisions be influenced by someone making
fun of any of the suggestions):
- absolute numbers for operator precedence are a hack that
reminds me strongly of my Basic times: I used steps of 100
starting with 1000 for line numbers, I used renum to make
space for additions or to clean up (was that refactoring?-),
but I was still happy to leave all that nonsense behind!
- googling for "operator precedence relative" suggests that some
parser generators already use something other that absolute
preferences
- prolog has more precedence levels, as well as simple declarations
for pre- and postfix operators (fx, xf)
sorry, I just couldn't resist any more;-)
claus
--
unsagePerformIO:
some things are just not wise to do
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