haskell-learning

##Just some notes about Haskell.

Don't use Tabs for layout method.
:t will return the type of whatever you pass to it:

Prelude> :t True
True :: Bool

The Numeric Types are: Int, Integer, Float, Double, Rational
() it's the same as void.
[] Lists holds a collection of item of the same type:

Prelude> [1,2,3] 
[1,2,3]

Prelude> ['H', 'e', 'l','l','o'] 
"Hello"

: operator appends an item to the beggining of a list:

Prelude> 1 : [2..10]
[1,2,3,4,5,6,7,8,9,10]

Tuples () hold a fixed number of items of different types:

Prelude> (1, True, "Hello", ['h','i'])
(1,True,"Hello","hi")

map function applied to a list in action:

Prelude> map (+ 5) [1 .. 5]
[6,7,8,9,10]

filter function applied to a list in action:

Prelude> filter (> 998) [1 .. 1000]
[999,1000]

We have Booleans True / False
there is &&, || (these are shortciruit version), and, or, not.
and / or receive a list of Booleans and evaluate them.
The expected if-then-else flow.
Haskell doesn't accept different types in the expression inside an if-then-else statement

if true
then 1
else "Hi"

won't be accepted by the compiler neither the interpreter.

== means equality and /= means inequality.
To create projects use Cabal
Stanza are rules that goes after the Header Library or Executable
If we want an src folder we need to add a Stanza rule like this

hs-source-dirs : src 
-- Or whatever folder we want

To create a module it must follow this Pattern A.B.C where A must be a folder, B too and C the file C.hs, this must be inside your src folder
To build the project we use cabal configure and cabal build.
The name of the functions must be lowercase (this is not a convention, is a Haskell rule).
The list of parameters should be separated by spaces (and not by commas) also we don't need parenthesis.
This is how we declare functions

nameOfFunction param1 param2 = bodyOfFunction

How to declare the Type that a function can receive

(+++) :: [Integer] -> [Integer] -> [Integer] 
lst1 +++ lst2 = bodyOfFunction -- We are defining with infix notation)

sumChars :: [Char] -> [Char] -> [Char]
sumChars param1 param2 = bodyOfFunction

jac1013/haskell-learning

haskell-learning