Why can I write a = 3 (badmatch)?
In Erlang, all variables must start with a capital letter, so you can write A = 3. but not a = 3. In the latter case Erlang complains that this is a “bad match”. In the second version, the ‘a’ is an atom while 3 is a number. ‘a’ cannot be pattern matched with 3. The use of capital letters for variables comes from Prolog. If the terms atom and pattern match are new to you, have a read of the first chapter or two of the Erlang book. (Very roughly, an atom corresponds to an enum in C and pattern matching in this case is like an assert statement.
