diff --git a/rebar.config b/rebar.config
index cfd8b45..db69d34 100644
--- a/rebar.config
+++ b/rebar.config
@@ -2,10 +2,18 @@
 
 {erl_opts, [debug_info]}.
 
-{deps, []}.  
+{deps, []}.
 
 {dialyzer, [
             {warnings, [unknown]},
             {plt_apps, all_deps},
             {base_plt_apps, [erts, kernel, stdlib]}
            ]}.
+
+{relx, [{release, {aessembler, "0.0.1"},
+         [aebytecode]},
+
+        {dev_mode, true},
+        {include_erts, false},
+
+        {extended_start_script, true}]}.
\ No newline at end of file
diff --git a/src/aefa_asm.erl b/src/aefa_asm.erl
index 6bf6d9e..a671e66 100644
--- a/src/aefa_asm.erl
+++ b/src/aefa_asm.erl
@@ -33,7 +33,7 @@
 %%%          <000>
 %%%          <1010>
 %%%          <>
-%%%          !<> 
+%%%          !<>
 %%%       9. Tuples
 %%%          ()
 %%%          (1, "foo")
@@ -60,7 +60,7 @@ format(Asm) -> format(Asm, 0).
 format([{comment, Comment} | Rest], Address) ->
     ";; " ++ Comment ++ "\n" ++ format(Rest, Address);
 format([Mnemonic | Rest], Address) ->
-    _Op = aefa_opcodes:m_to_op(Mnemonic),
+    _Op = aefa_opcode:m_to_op(Mnemonic),
     "        " ++ atom_to_list(Mnemonic) ++ "\n"
         ++ format(Rest, Address + 1);
 format([],_) -> [].
@@ -79,7 +79,9 @@ file(Filename, Options) ->
             ok
     end,
 
-    ByteList = to_bytecode(Tokens, 0, #{}, [], Options),
+    Env = to_bytecode(Tokens, none, #{}, [], Options),
+
+    ByteList = serialize(Env),
 
     case proplists:lookup(pp_hex_string, Options) of
         {pp_hex_string, true} ->
@@ -88,19 +90,27 @@ file(Filename, Options) ->
             ok
     end,
 
+    {Env, list_to_binary(ByteList)}.
 
-    list_to_binary(ByteList).
+serialize(Env) ->
+    %% TODO: add serialization of immediates
+    %% TODO: add serialization of function definitions
+    Code = [C || {_Name, {_Sig, C}} <- maps:to_list(Env)],
+    Code.
 
 to_hexstring(ByteList) ->
     "0x" ++ lists:flatten(
               [io_lib:format("~2.16.0b", [X])
                || X <- ByteList]).
 
-
+to_bytecode([{function,_line, 'FUNCTION'}|Rest], Address, Env, Code, Opts) ->
+    Env2 = insert_fun(Address, Code, Env),
+    {Fun, Rest2} = to_fun_def(Rest),
+    to_bytecode(Rest2, Fun, Env2, [], Opts);
 to_bytecode([{mnemonic,_line, Op}|Rest], Address, Env, Code, Opts) ->
-    OpCode = aefa_opcodes:m_to_op(Op),
-    OpSize = aefa_opcodes:op_size(OpCode),
-    to_bytecode(Rest, Address + OpSize, Env, [OpCode|Code], Opts);
+    OpCode = aefa_opcode:m_to_op(Op),
+    %% TODO: arguments
+    to_bytecode(Rest, Address, Env, [OpCode|Code], Opts);
 to_bytecode([{int,_line, Int}|Rest], Address, Env, Code, Opts) ->
     to_bytecode(Rest, Address, Env, [Int|Code], Opts);
 to_bytecode([{hash,_line, Hash}|Rest], Address, Env, Code, Opts) ->
@@ -109,23 +119,63 @@ to_bytecode([{id,_line, ID}|Rest], Address, Env, Code, Opts) ->
     to_bytecode(Rest, Address, Env, [{ref, ID}|Code], Opts);
 to_bytecode([{label,_line, Label}|Rest], Address, Env, Code, Opts) ->
     to_bytecode(Rest, Address, Env#{Label => Address}, Code, Opts);
-to_bytecode([], _Address, Env, Code, Opts) ->
+to_bytecode([], Address, Env, Code, Opts) ->
+    Env2 = insert_fun(Address, Code, Env),
     case proplists:lookup(pp_opcodes, Opts) of
         {pp_opcodes, true} ->
-            io:format("opcodes ~p~n", [lists:reverse(Code)]);
+            Ops = [C || {_Name, {_Sig, C}} <- maps:to_list(Env2)],
+            io:format("opcodes ~p~n", [Ops]);
         none ->
             ok
     end,
+    Env2.
+
+
+to_fun_def([{id, _, Name}, {'(', _} | Rest]) ->
+    {ArgsType, [{'->', _} | Rest2]} = to_arg_types(Rest),
+    {RetType, Rest3} = to_type(Rest2),
+    {{Name, ArgsType, RetType}, Rest3}.
+
+to_arg_types([{')', _} | Rest]) -> {[], Rest};
+to_arg_types(Tokens) ->
+    case to_type(Tokens) of
+        {Type, [{',', _} |  Rest]} ->
+            {MoreTypes, Rest2} = to_arg_types(Rest),
+            {[Type|MoreTypes], Rest2};
+        {Type, [{')', _} |  Rest]} ->
+            {[Type], Rest}
+    end.
+
+to_type([{id, _, "integer"} | Rest]) -> {integer, Rest};
+to_type([{id, _, "boolean"} | Rest]) -> {boolean, Rest};
+to_type([{id, _, "string"}  | Rest]) -> {string, Rest};
+to_type([{id, _, "address"} | Rest]) -> {address, Rest};
+to_type([{id, _, "bits"}    | Rest]) -> {bits, Rest};
+to_type([{'{', _}, {id, _, "list"}, {',', _} | Rest]) ->
+    %% TODO: Error handling
+    {ListType, [{'}', _}| Rest2]} = to_type(Rest),
+    {{list, ListType}, Rest2};
+to_type([{'{', _}, {id, _, "tuple"}, {',', _}, {'[', _} | Rest]) ->
+    %% TODO: Error handling
+    {ElementTypes, [{'}', _}| Rest2]} = to_list_of_types(Rest),
+    {{tuple, ElementTypes}, Rest2};
+to_type([{'{', _}, {id, _, "map"}, {',', _} | Rest]) ->
+    %% TODO: Error handling
+    {KeyType, [{',', _}| Rest2]} = to_type(Rest),
+    {ValueType, [{'}', _}| Rest3]} = to_type(Rest2),
+    {{map, KeyType, ValueType}, Rest3}.
+
+to_list_of_types([{']', _} | Rest]) -> {[], Rest};
+to_list_of_types(Tokens) ->
+    case to_type(Tokens) of
+        {Type, [{',', _} |  Rest]} ->
+            {MoreTypes, Rest2} = to_list_of_types(Rest),
+            {[Type|MoreTypes], Rest2};
+        {Type, [{']', _} |  Rest]} ->
+            {[Type], Rest}
+    end.
 
-    PatchedCode = resolve_refs(Code, Env, []),
-    case proplists:lookup(pp_patched_code, Opts) of
-        {pp_patched_code, true} ->
-            io:format("Patched Code: ~p~n", [PatchedCode]);
-        none ->
-            ok
-    end,
 
-    expand_args(PatchedCode).
 
 %% Also reverses the code (back to unreversed state).
 resolve_refs([{ref, ID} | Rest], Env, Code) ->
@@ -138,3 +188,7 @@ resolve_refs([],_Env, Code) -> Code.
 expand_args([OP | Rest]) ->
     [OP | expand_args(Rest)];
 expand_args([]) -> [].
+
+insert_fun(none, [], Env) -> Env;
+insert_fun({Name, Type, RetType}, Code, Env) ->
+    Env#{Name => {{Type, RetType}, lists:reverse(Code)}}.
diff --git a/src/aefa_asm_scan.xrl b/src/aefa_asm_scan.xrl
index af3b7c6..3473418 100644
--- a/src/aefa_asm_scan.xrl
+++ b/src/aefa_asm_scan.xrl
@@ -18,13 +18,15 @@ HASH     = #{HEXDIGIT}+
 WS       = [\000-\s]
 ID       = {LOWER}[a-zA-Z0-9_]*
 
-Rules.
-{ID}           : {token, {id, TokenLine, TokenChars }}.
 
-NOP            : {token, {mnemonic, TokenLine, 'NOP'}}.
+Rules.
+%%{ID}           : {token, {id, TokenLine, TokenChars }}.
 
 RETURN         : {token, {mnemonic, TokenLine, 'RETURN'}}.
 CALL           : {token, {mnemonic, TokenLine, 'CALL'}}.
+FUNCTION       : {token, {function, TokenLine, 'FUNCTION' }}.
+NOP            : {token, {mnemonic, TokenLine, 'NOP'}}.
+
 CALL_R         : {token, {mnemonic, TokenLine, 'CALL_R'}}.
 CALL_T         : {token, {mnemonic, TokenLine, 'CALL_T'}}.
 CALL_TR        : {token, {mnemonic, TokenLine, 'CALL_TR'}}.
@@ -127,14 +129,15 @@ COMMENT        : {token, {mnemonic, TokenLine, 'COMMENT'}}.
 
 
 %% Symbols
+\-\>  : {token, {'->', TokenLine}}.
 ,   : {token, {',', TokenLine}}.
 \.  : {token, {'.', TokenLine}}.
 \(  : {token, {'(', TokenLine}}.
 \)  : {token, {')', TokenLine}}.
 \[  : {token, {'[', TokenLine}}.
 \]  : {token, {']', TokenLine}}.
-{   : {token, {'{', TokenLine}}.
-}   : {token, {'}', TokenLine}}.
+\{  : {token, {'{', TokenLine}}.
+\}  : {token, {'}', TokenLine}}.
 
 
 %% Whitespace ignore
@@ -153,7 +156,7 @@ Erlang code.
 
 -ignore_xref([format_error/1, string/2, token/2, token/3, tokens/2, tokens/3]).
 
--include_lib("aebytecode/include/aeb_opcodes.hrl").
+-include_lib("aebytecode/include/aefa_opcodes.hrl").
 
 
 parse_hex("0x" ++ Chars) -> list_to_integer(Chars, 16).
diff --git a/src/aefa_opcode.erl b/src/aefa_opcode.erl
index 4563f81..2c726ff 100644
--- a/src/aefa_opcode.erl
+++ b/src/aefa_opcode.erl
@@ -22,11 +22,13 @@
 opcode(X) when X >= 0, X =< 255 -> X;
 opcode({comment,X}) -> ?COMMENT(X).
 
-mnemonic(?NOP)           -> 'NOP'           ;
-mnemonic({comment,_})     -> 'COMMENT'        .
+mnemonic(?NOP)         -> 'NOP'        ;
+mnemonic({comment,_})  -> 'COMMENT'    .
 
-m_to_op('NOP')             -> ?NOP           ;
-m_to_op('COMMENT')        -> ?COMMENT("")    ;
-m_to_op(Data) when 0=<Data, Data=<255
-                          -> Data            .
+m_to_op('NOP')         -> ?NOP         ;
+m_to_op('COMMENT')     -> ?COMMENT("") ;
+m_to_op('RETURN')      -> ?RETURN      ;
+m_to_op('PUSH')        -> ?PUSH        ;
+m_to_op('JUMP')        -> ?JUMP        ;
+m_to_op(Data) when 0=<Data, Data=<255 -> Data.
 
diff --git a/test/asm_code/identity.fate b/test/asm_code/identity.fate
new file mode 100644
index 0000000..a2350dc
--- /dev/null
+++ b/test/asm_code/identity.fate
@@ -0,0 +1,8 @@
+;; CONTRACT: Identity
+FUNCTION id(integer) ->  integer
+  RETURN
+
+;; Test the code from the shell
+;; _build/default/rel/aessembler/bin/aessembler console
+
+;; aeb_aefa:file("../../../../test/asm_code/identity.fate", []).
diff --git a/test/asm_code/test.fate b/test/asm_code/test.fate
new file mode 100644
index 0000000..d4bf55b
--- /dev/null
+++ b/test/asm_code/test.fate
@@ -0,0 +1,23 @@
+;; CONTRACT: Test
+FUNCTION id(integer) -> integer
+  RETURN
+
+FUNCTION jumps() -> integer
+  PUSH 0
+  JUMP 3
+  NOP
+  JUMP 2
+  NOP
+  RETURN
+  NOP
+  JUMP 1
+
+FUNCTION inc(integer) -> integer
+  INC arg0
+  INC
+  RETURN
+
+;; Test the code from the shell
+;; _build/default/rel/aessembler/bin/aessembler console
+
+;; aeb_aefa:file("../../../../test/asm_code/test.fate", []).