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Diffstat (limited to 'haskell.html.markdown')
| -rw-r--r-- | haskell.html.markdown | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/haskell.html.markdown b/haskell.html.markdown index 4e254070..90d47c27 100644 --- a/haskell.html.markdown +++ b/haskell.html.markdown @@ -1,5 +1,6 @@ --- language: Haskell +filename: learnhaskell.hs contributors: - ["Adit Bhargava", "http://adit.io"] --- @@ -123,6 +124,9 @@ last [1..5] -- 5 fst ("haskell", 1) -- "haskell" snd ("haskell", 1) -- 1 +-- pair element accessing does not work on n-tuples (i.e. triple, quadruple, etc) +snd ("snd", "can't touch this", "da na na na") -- error! see function below + ---------------------------------------------------- -- 3. Functions ---------------------------------------------------- @@ -158,8 +162,8 @@ fib 1 = 1 fib 2 = 2 fib x = fib (x - 1) + fib (x - 2) --- Pattern matching on tuples: -foo (x, y) = (x + 1, y + 2) +-- Pattern matching on tuples +sndOfTriple (_, y, _) = y -- use a wild card (_) to bypass naming unused value -- Pattern matching on lists. Here `x` is the first element -- in the list, and `xs` is the rest of the list. We can write @@ -202,11 +206,11 @@ foo = (4*) . (10+) foo 5 -- 60 -- fixing precedence --- Haskell has an operator called `$`. This operator applies a function --- to a given parameter. In contrast to standard function application, which --- has highest possible priority of 10 and is left-associative, the `$` operator +-- Haskell has an operator called `$`. This operator applies a function +-- to a given parameter. In contrast to standard function application, which +-- has highest possible priority of 10 and is left-associative, the `$` operator -- has priority of 0 and is right-associative. Such a low priority means that --- the expression on its right is applied as the parameter to the function on its left. +-- the expression on its right is applied as a parameter to the function on its left. -- before even (fib 7) -- false @@ -222,7 +226,7 @@ even . fib $ 7 -- false -- 5. Type signatures ---------------------------------------------------- --- Haskell has a very strong type system, and every valid expression has a type. +-- Haskell has a very strong type system, and every valid expression has a type. -- Some basic types: 5 :: Integer @@ -443,5 +447,6 @@ qsort (p:xs) = qsort lesser ++ [p] ++ qsort greater There are two popular ways to install Haskell: The traditional [Cabal-based installation](http://www.haskell.org/platform/), and the newer [Stack-based process](https://www.stackage.org/install). You can find a much gentler introduction from the excellent -[Learn you a Haskell](http://learnyouahaskell.com/) or +[Learn you a Haskell](http://learnyouahaskell.com/), +[Happy Learn Haskell Tutorial](http://www.happylearnhaskelltutorial.com/) or [Real World Haskell](http://book.realworldhaskell.org/). |