Haskell

Class: CSE 114A Subject: computer-science haskell Date: 2026-01-28 Teacher: **Prof. Miller

Functions, Types, let & where

Functions

in_range min max x = 
	x >= min && x <= max
	
in_range 0 5 3
	=> True
	
in_range 4 5 3
	=> False

Functions(let)

• the let keyword let’s you store expressions in intermediary variables

in_range min max x = 
	let in_lower_bound = min <= x
		in_upper_bound = max >= x
	in
	in_lower_bound && in_upper_bound

Functions(where)

in_range min max x = ilb && iub
where
	ilb = min <= x
	iub = max >= x

Functions(if)

in_range min max x =
if ilb then iub else False
where
	ilb = min <= x
	iub max >= x 

Types

x :: Integer
x = 1
 
y :: Bool
y = True
 
z :: Float
z = 3.1415

Types(Functions)

in_range :: Integer -> Integer -> Integer -> Bool -- 3 Integer args, Bool ret
in_range min max x = 
	x >= min && x <= max
	
in_range 0.5 1.5 1 -- Type error
in_range 0 5 3 -- Correct