Is the assignment operator really “just” an operator?

Question

My question was triggered by this discussion on SO, which did not lead to an answer that would really explain the issue. I am "rewriting" it here in a slightly differe

Answer 1

I think the understanding of 1 && (a = 3) is, understandably, mislead.

a = false
b = 1
b && a = 3
b
=> 1
a
=> 3

Why is a being assigned to in the && expression when a is false? Should the && expression not return when encountering a false value? Spoiler, it does return!

Taking a step back, we think of the purpose of the && operator to control the flow of logic. Our disposition to the statement

1 && a = 3

is to assume the entire statement is returned if a is nil or false. Well no, the interpreter is evaluating like so:

(1 && a) = 3

The interpreter does not raise a if it is nil or false nor does it return the left side if a is nil or false

a = nil
1 && a
=> nil # a was returned

The interpreter returns the variable, this is why the original statement can be read:

a = 3

due to 1 && a returning a which is a variable that can be assigned to by the = operand on the second half of the statement.

TLDR

In your origin example: 1 is neither nil nor false so the variable a is returned in (1 && a) which is subsequently assigned in a = 3