iskm/learnxinyminutes-docs
1
0
Fork 0
mirror of https://github.com/adambard/learnxinyminutes-docs.git synced 2025-04-27 07:33:57 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Merge pull request #3157 from alexgrejuc/master

Browse Source 
[haskell/en] tweaked tuple information to demonstrate wildcards and a more useful tuple function
This commit is contained in:
Adam Bard 2018-09-08 09:48:48 -07:00 committed by GitHub
commit e6b01188bf
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 10 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
haskell.html.markdown
View File

@ -124,6 +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
----------------------------------------------------
@ -159,8 +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
@ -203,11 +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
@ -223,7 +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