From d88b7f8bcf9c509ff5d374fec9cc6054fb656657 Mon Sep 17 00:00:00 2001
From: Kyle Isom <kyle@imap.cc>
Date: Thu, 25 Apr 2019 23:02:54 -0700
Subject: [PATCH] Finishing up part 1.

---
 pe/a.erl        | 16 ++++++++++++++++
 pe/b.erl        |  4 ++++
 pe/chapter8.erl | 20 ++++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 pe/a.erl
 create mode 100644 pe/b.erl
 create mode 100644 pe/chapter8.erl

diff --git a/pe/a.erl b/pe/a.erl
new file mode 100644
index 0000000..3449460
--- /dev/null
+++ b/pe/a.erl
@@ -0,0 +1,16 @@
+-module(a).
+-compile(export_all).
+
+start(Tag) ->
+    spawn(fun () -> loop(Tag) end).
+
+loop(Tag) ->
+    sleep(),
+    Val = b:x(),
+    io:format("Vsn1 (~p) b:x() = ~p~n", [Tag, Val]).
+    loop(Tag).
+
+sleep() ->
+    receive
+	after 3000 -> true
+    end.
diff --git a/pe/b.erl b/pe/b.erl
new file mode 100644
index 0000000..6febccd
--- /dev/null
+++ b/pe/b.erl
@@ -0,0 +1,4 @@
+-module(b).
+-export([x/0]).
+
+x () -> 1.
diff --git a/pe/chapter8.erl b/pe/chapter8.erl
new file mode 100644
index 0000000..a6ad3ad
--- /dev/null
+++ b/pe/chapter8.erl
@@ -0,0 +1,20 @@
+-module(chapter8).
+-export([unique_funs/0]).
+
+%% The command code:all_loaded() returns a list of {Mod,File} pairs of
+%% all modules that have been loaded into the Erlang system. Use the
+%% BIF Mod:module_info() to find out about these modules. Write
+%% functions to determine which module exports the most functions and
+%% which function name is the most common. Write a function to find
+%% all unambiguous function names, that is, function names that are
+%% used in only one module.
+unique_funs() ->
+    unique_funs(code:all_loaded(), sets:new()).
+
+unique_funs([], UniqueFuns) ->
+    {sets:size(UniqueFuns), sets:to_list(UniqueFuns)};
+unique_funs([{Mod, _File}|T], UniqueFuns) ->
+    Funs = lists:map(fun ({Fun, _Arity}) -> Fun end, Mod:module_info(exports)),
+    unique_funs(T, sets:union(UniqueFuns, sets:from_list(Funs))).
+    
+