[Haskell-beginners] [x] and (x:_) for lists -- did you ever think that odd?

AntC anthony_clayden at clear.net.nz
Tue May 22 02:36:47 CEST 2012


Brandon Allbery <allbery.b <at> gmail.com> writes:

> You missed experienced Lispers, who are likewise entirely comfortable with 
cons-like notation.

Good point Brandon, I should have asked what background and expectations 
people were coming from. From ALGOL, square brackets mean arrays, which are 
close-ish to lists(?)

(For Lispers: does it seem odd using colon? Does it seem odd that dot is 
function composition, not cons pairing?)

I was more getting at the oddness (or perhaps not) of having two different 
notations.

> 
> I would want to very carefully check the implications of your suggestion:

No, I wasn't anywhere near making a "suggestion" or "proposal". Just asking 
for people's impressions.

> it might not integrate well with the rest of pattern matching syntax, ...

FWIW, the double-dot notation is not currently valid in a pattern.

I wanted to show something with square brackets. And to my mind, the double-
dot could be taken as an unknown-length tail of the list, like an ellipsis. 
But others (it seems) think of it as enumFrom.

AntC





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