Connections: Erlang
Starting Out
The Shell
Start with erl
User switch command is ^G
Variables
Must start with an uppercase (because atoms are lowercase)
Operate on pattern matching under the hood
-
ie One = 1. One = 2 + 1.
> exception error: no match of right hand side value 3
Atoms
Must start with a lowercase (because variables are uppercase)
Can be enclosed in single quotes if not starting with an uppercase, or if it contains other alphanumeric characters other than _ or @.
Should never be generated dynamically, as they aren’t garbage collected and will pile up in memory.
Boolean Algebra and Comparison Operators
true, false, and, or, xor, not
5 : 5 → true
1 =:= 0 → false
1 / 0 → true
5 : 5.0 → false
5 == 5.0 → true
5 /= 5.0 → false
Tuples
PreciseTemperature = {celsius, 23.212}.
Lists
Can store multiple types
- [1, 2, 3, {numbers, [4,5,6]}, 5.34, atom].
Watch out! Strings are lists of numbers
- [97, 98, 99] → “abc”
- Erlang will print lists of numbers as numbers only when at least one of them could not also represent a letter
List concatenation is done with ++
- [1,2] ++ [3,4] = [1, 2, 3, 4]
List removal is done with —
- [1,2,3,4] — [3,4] → [1,2]
List Comprehension
- [2*N || N ← [1,2,3,4]]