Modules

Modules

1. a collection of

   • Functions
     • Types
       • typeclasses
         • related to each other

2. Advantages

   • reuse of functions
   • organization

3. haskell standard library

   • divided into modules
     • specific use
       • List manipulation
       • concurrent progtramming
       • a complex number module

4. syntax

   • import <module name>
   • in the header
   • each in separate rows
   • example
     • in GHCi
       • :m + Data.list
     • in Script
       • the whole module
         • import Data.list
       • specific functions
         • import Data.List (nub, sort)

5. Types

   • Data.List
     • Intersperse
       • intersperse 0 [1,2,3]
         • [1,0,2,0,3]
     • Intercalate
       • intercalate " " ["A","B","C"]
         • "A B C"
     • Transpose
     • concat
       • concat ["car","los"]
         • "carlos"
     • concatMap
       • applies function and concatenates
     • Boolean checks
       • and
         • apply function to a list
           • returns true if everything is true
       • or
         • returns true if the validation of an element is true
       • any
       • all
     • iterate
       • applies a function to an element, reapplies it to the result
     • splitAt
       • splitAt 6 "carlosmarin"
         • ("carlos","marin")
     • takeWhile
       • take elements as long as the result is true
     • dropWhile
       • discard element while the condition is true
     • returns a pair of lists
       • span
         • divides when the predicate is false
       • Break
         • divides when the predicate is true
     • sort
       • sorts a list
     • group
       • group equal elements
     • inits
       • inits "carlos"
         • ["","c","ca","car","carl","carlo","carlos"]
     • tails
       • tails "casa"
         • ["casa","asa","sa","a",""]
     • Search functions
       • isInfixOf
         • search for a string in the whole list
       • isPrefixOf
         • look for a string at the beginning of a list
       • isSuffixOf
         • Look for a string at the end of a list
       • elem
       • notElem
       • find
         • returns the first element that fulfills the predicate
           • as a maybe element
         • findIndex
         • findIndices
     • partition
       • Take a list and a predicate
         • returns a tuple
           • the first element fulfills the predicate
           • the second element is the rest
     • elemIndex
       • returns one index
     • elemIndices
       • returns multiple index
     • lines
       • lines "carlos\npuentes"
         • ["carlos","puentes"]
     • unlines
       • unlines ["hola","mundo"]
         • "hola\nmundo"
     • words
       • separate lines of text by words
     • unwords
       • the opposite of words
     • delete
       • delete the first element that matches
     • \\
       • removes items from one list in another
     • Union
     • intersect
     • insert
   • Data.char
     • Handles characters or lists of these
       • check its properties
     • functions
       • isSpace
         • check its properties
           • check if a character is a space
       • isLower
         • lower case
       • isUpper
         • Upper case
       • isAlpha
       • isAlphaNum
       • isPrim
       • isDigit
       • isLetter
       • isNumber
       • isPunctuation
       • isSymbol
   • Data.map
     • Association lists
       • used to store key-value pairs
         • [(k,v)]
     • Functions
       • fromList
       • Empty
       • insert
       • null
       • size
       • singleton
       • lookup
       • member
   • Data.set
     • working with sets
     • functions
       • intersection
       • fromList
       • difference
       • union
       • null
       • size
       • member
       • empty
       • singleton
       • insert
       • delete