Difference between revisions of "PreludeTour"

Latest revision as of 15:19, 6 February 2021

type:	`abs :: Num a => a -> a`
description:	returns the absolute value of a number.
definition:	abs x \| x >= 0 = x \| otherwise = -x
usage:	Prelude> abs (-3) 3

type:	`all :: (a -> Bool) -> [a] -> Bool`
description:	Applied to a predicate and a list, returns True if all elements of the list satisfy the predicate, and False otherwise. Similar to the function #any.
definition:	all p xs = and (map p xs)
usage:	Prelude> all (<11) [1..10] True Prelude> all isDigit "123abc" False

@@ Line 1: / Line 1: @@
 == A Tour of the Haskell Prelude ==
+;<span id="abs">'''abs'''</span>:
+{| border="0" cellpadding="4"
+|-
+| ''type:'' || <hask>abs :: Num a => a -> a</hask>
+|-
+| ''description:'' || returns the absolute value of a number.
+|-
+| ''definition:''
+| <haskell>
+abs x
+  | x >= 0 = x
+  | otherwise = -x
+</haskell>
+|-
+| ''usage:''
+| <pre>
+Prelude> abs (-3)
+</pre>
+|}
+;<span id="all">'''all'''</span>:
+{| border="0" cellpadding="4"
+|-
+| ''type:'' || <hask>all :: (a -> Bool) -> [a] -> Bool</hask>
+|-
+| ''description:'' || Applied to a predicate and a list, returns True if all elements of the list satisfy the predicate, and False otherwise. Similar to the function [[#any]].
+|-
+| ''definition:''
+| <haskell>
+all p xs = and (map p xs)
+</haskell>
+|-
+| ''usage:''
+| <pre>
+Prelude> all (<11) [1..10]
+True
+Prelude> all isDigit "123abc"
+False
+</pre>
+|}