Hidden Features of Erlang [closed]

Answer 1

.erlang can preload libraries and run commands on a shells startup, you can also do specific commands for specific nodes by doing a case statement on node name.

Answer 2

If you want to execute more than one expression in a list comprehension, you can use a block. For example:

> [begin erlang:display(N), N*10 end || N <- lists:seq(1,3)].
1
2
3
[10,20,30]

Answer 3

Parameterized Modules! From http://www.lshift.net/blog/2008/05/18/late-binding-with-erlang and http://www.erlang.se/euc/07/papers/1700Carlsson.pdf

-module(myclass, [Instvar1, Instvar2]).
-export([getInstvar1/0, getInstvar2/0]).
getInstvar1() -> Instvar1.
getInstvar2() -> Instvar2.

And

Eshell V5.6  (abort with ^G)
1> Handle = myclass:new(123, 234).
{myclass,123,234}
2> Handle:getInstvar1().
123
3> Handle:getInstvar2().
234

Answer 4

Inheritance! http://www.erlang.se/euc/07/papers/1700Carlsson.pdf

Parent

-module(parent).
-export([foo/0, bar/0]).

foo() ->
    io:format("parent:foo/0 ~n", []).

bar() ->
    io:format("parent:bar/0 ~n", []).

Child

-module(child).
-extends(parent).
-export([foo/0]).

foo() ->
    io:format("child:foo/0 ~n", []).

Console

23> parent:foo().
parent:foo/0 
ok
24> parent:bar().
parent:bar/0 
ok
25> child:foo().
child:foo/0 
ok
26> child:bar().
parent:bar/0 
ok

Answer 5

.erlang_hosts gives a nice way to share names across machines

Answer 6

Not so hidden, but one of the most important aspects, when chosing Erlang as platform for development:

• Possibility of enhanced tracing on live nodes (in-service) and being one of the best in debugging!