Douglas Philips wrote:
What would be the proper way to propose that:
( exp1 , ... , expk ) (tuple, k>=2)
[ exp1 , ... , expk ] (list, k>=1)
be amended to:
( exp1 , ... , expk [ , ] ) (tuple, k>=2)
[ exp1 , ... , expk [ , ] ] (list, k>=1)
I think a problem with the above proposal is that by allowing an optional
trailing comma the compiler can no longer detect as an error the case where
the programmer has simply just forgotten to fill in the last element of the
tuple/list. The existing syntax forces the user to do some extra work
fiddling about with commas but the reward is that the compiler can verify
that you haven't forgotten the last argument.
About a year ago I proposed (on the cafe) a syntax sugar to avoid commas in
tuples and lists which made use of the layout rule something like:
let a = #[ -- introduces new layout block
first
second
third
let b = #(
one
two
As an aside it would also be nice to be able to use layout for function
arguments as in:
do
a <- foo
#bracket_
enter
exit
action
the general idea being that '#' immediately followed by an identifier (which
may be qualified) or the symbol '(' or '[' would start a layout block. ('#'
of course would no longer be able to be used in symbolic identifiers)
Brian.
--
http://www.metamilk.com
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