Although in Erlang it's closer to an equation with assignment being a side effect. `=` is the pattern matching operator.

    Eshell V15.2.6 (press Ctrl+G to abort, type help(). for help)
    1> X = 1.
    1
    2> X = X.
    1
    3> 1 = X.
    1
    4> X = 2.
    ** exception error: no match of right hand side value 2
    5>