universal-calculator/README.md

The Universal Calculator

Using the GHC REPL and Haskell to teach programming concepts through the guise of mathematics.
A handy assistant to help you understand and solve maths problems.

• GHC = Glasgow Haskell Compiler
• REPL = Read Evaluate Print Loop
• Haskell = Lazy, Pure, Functional Programming Language

How to use

λ> 5 * 5
25

λ> 1 + 5
6

λ> 10 / 2
5.0

λ> 10 `div` 2
5

λ> 10 `div` 3
3

λ> 10 / 3
3.3333333333333335

λ> :t sum
sum :: (Foldable t, Num a) => t a -> a

λ> :t sum [1..100]
sum [1..100] :: (Num a, Enum a) => a

λ> sum [1..100]
5050

λ> f x = 5*x^3 + 4*x + 2

λ> f 1
11

λ> f 10
5042

λ> f 100
5000402

λ> map f [1..10]
[11,50,149,338,647,1106,1745,2594,3683,5042]

λ> putStrLn "Hello, world!"
Hello, world!

How to install

• Use the DeterminateSystems installer to install Nix with Flakes.
  • https://github.com/DeterminateSystems/nix-installer
• cd into the top level of this repo.
• nix develop and let Nix load the flake and set everything up.
• ghci and get computing!
  • To enable performance timings after every input, type λ> :set +s in the REPL
  • See other initial commands being run in the .ghci file.