fay-jai/programming-elixir-ch2.ex

## programming-elixir-ch2.ex
# Pattern Matching in Elixir

# Basic pattern matching examples
a = 1 # In order for this to match, 'a' must be bound to the value of 1

1 = a # Since a is already bound to the value of 1, this looks more like 1 = 1. And in that case, the match will be successful.

2 = a # Since a is already bound to the value of 1, this looks more like 2 = 1. This match will fail since we can't make both sides match in value.

# Pattern matching examples with lists
list = [1, 2, 3] # In order for the left and right hand sides to match in both structure and value, the left hand side 'list' must be bound to the value [1, 2, 3]

[a, b, c] = [1, 2, 3] # In order for the left and right hand sides to match in both structure and value, Elixir can bind 1 to a, 2 to b, and 3 to c.

[a, b] = [1, 2, 3] # This match will fail because there's no way to match both sides in structure and value

# Special cases
[a, a] = [1, 1] # During a given match, Elixir will perform pattern matching from left to right. Also once Elixir has bound a variable to a value in a given match, that variable will be bound to that value for the entirety of the given match. In this example, what this means is that when the 1st 'a' on the left is encountered, it will be bound to 1 and when the 2nd 'a' is encountered, the value of a is already 1 and the match will look more like 1 = 1. Hence this match will be successful.
[a, a] = [1, 2] # From the above example, we should know that the 1st 'a' will be bound to 1, and when the 2nd 'a' is encountered, the match is more like 2 = 1. Hence this match will fail.

a = 1
[^a, b] = [1, 2] # The ^ operator is called the pin operator because when it is encountered, it pins and uses the current value of the variable to perform the match. In other words, this match is more like [1, b] = [1, 2] and this will match successfully when b is bound to 2.
	# Pattern Matching in Elixir

	# Basic pattern matching examples
	a = 1 # In order for this to match, 'a' must be bound to the value of 1

	1 = a # Since a is already bound to the value of 1, this looks more like 1 = 1. And in that case, the match will be successful.

	2 = a # Since a is already bound to the value of 1, this looks more like 2 = 1. This match will fail since we can't make both sides match in value.

	# Pattern matching examples with lists
	list = [1, 2, 3] # In order for the left and right hand sides to match in both structure and value, the left hand side 'list' must be bound to the value [1, 2, 3]

	[a, b, c] = [1, 2, 3] # In order for the left and right hand sides to match in both structure and value, Elixir can bind 1 to a, 2 to b, and 3 to c.

	[a, b] = [1, 2, 3] # This match will fail because there's no way to match both sides in structure and value

	# Special cases
	[a, a] = [1, 1] # During a given match, Elixir will perform pattern matching from left to right. Also once Elixir has bound a variable to a value in a given match, that variable will be bound to that value for the entirety of the given match. In this example, what this means is that when the 1st 'a' on the left is encountered, it will be bound to 1 and when the 2nd 'a' is encountered, the value of a is already 1 and the match will look more like 1 = 1. Hence this match will be successful.
	[a, a] = [1, 2] # From the above example, we should know that the 1st 'a' will be bound to 1, and when the 2nd 'a' is encountered, the match is more like 2 = 1. Hence this match will fail.

	a = 1
	[^a, b] = [1, 2] # The ^ operator is called the pin operator because when it is encountered, it pins and uses the current value of the variable to perform the match. In other words, this match is more like [1, b] = [1, 2] and this will match successfully when b is bound to 2.