Hi, I’m modelling fractions with a view to looking at continued fractions and I have this recursive structure. type Numerator = Integer data Fraction = Numbr Integer | F Numerator Fraction in ghci I do λ-> :t F 1 (Numbr 2) F 1 (Numbr 2) :: Fraction which is fine. But what surprised me is that it also works without using Numbr e.g. λ-> :t F 1 2 F 1 2 :: Fraction why is this? Thanks Mike
The only thing I can think of is that you wrote a Num instance for Fraction. That allows it to represent a fraction as a literal 2 because you can create a fraction from an integer via fromInteger. On Wed, Nov 8, 2017 at 2:21 PM, mike h <mike_k_houghton@yahoo.co.uk> wrote:
Hi,
I’m modelling fractions with a view to looking at continued fractions and I have this recursive structure.
type Numerator = Integer data Fraction = Numbr Integer | F Numerator Fraction
in ghci I do
λ-> :t F 1 (Numbr 2) F 1 (Numbr 2) :: Fraction
which is fine. But what surprised me is that it also works without using Numbr e.g.
λ-> :t F 1 2 F 1 2 :: Fraction
why is this?
Thanks
Mike _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
Duh! Give that man a ceeeegar! Thanks :)
On 8 Nov 2017, at 19:31, David McBride <toad3k@gmail.com> wrote:
The only thing I can think of is that you wrote a Num instance for Fraction. That allows it to represent a fraction as a literal 2 because you can create a fraction from an integer via fromInteger.
On Wed, Nov 8, 2017 at 2:21 PM, mike h <mike_k_houghton@yahoo.co.uk <mailto:mike_k_houghton@yahoo.co.uk>> wrote: Hi,
I’m modelling fractions with a view to looking at continued fractions and I have this recursive structure.
type Numerator = Integer data Fraction = Numbr Integer | F Numerator Fraction
in ghci I do
λ-> :t F 1 (Numbr 2) F 1 (Numbr 2) :: Fraction
which is fine. But what surprised me is that it also works without using Numbr e.g.
λ-> :t F 1 2 F 1 2 :: Fraction
why is this?
Thanks
Mike _______________________________________________ Beginners mailing list Beginners@haskell.org <mailto:Beginners@haskell.org> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners <http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners>
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