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-rw-r--r--lib/syntax_tools/examples/merl/Makefile22
-rw-r--r--lib/syntax_tools/examples/merl/basic.erl77
-rw-r--r--lib/syntax_tools/examples/merl/basic_test.erl77
-rw-r--r--lib/syntax_tools/examples/merl/basicc.erl149
-rw-r--r--lib/syntax_tools/examples/merl/lisp.erl160
-rw-r--r--lib/syntax_tools/examples/merl/lisp_test.erl98
-rw-r--r--lib/syntax_tools/examples/merl/lispc.erl102
-rw-r--r--lib/syntax_tools/examples/merl/merl_build.erl104
8 files changed, 789 insertions, 0 deletions
diff --git a/lib/syntax_tools/examples/merl/Makefile b/lib/syntax_tools/examples/merl/Makefile
new file mode 100644
index 0000000000..13a9703733
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/Makefile
@@ -0,0 +1,22 @@
+EBIN=../../ebin
+INCLUDES=../../include
+SOURCES=merl_build.erl lisp.erl lispc.erl basic.erl basicc.erl
+HEADERS=$(INCLUDES)/merl.hrl
+OBJECTS=$(SOURCES:%.erl=%.beam)
+ERLC_FLAGS=+debug_info -I$(INCLUDES) -pa $(EBIN)
+
+all: $(OBJECTS) test
+
+%.beam: %.erl $(HEADERS) Makefile
+ erlc $(ERLC_FLAGS) -o ./ $<
+
+# additional dependencies due to the parse transform
+lispc.beam basicc.beam: $(EBIN)/merl_transform.beam $(EBIN)/merl.beam
+
+clean:
+ -rm -f $(OBJECTS)
+
+test:
+ erl -noshell -pa $(EBIN) \
+ -eval 'eunit:test([lisp, lispc, basic, basicc],[])' \
+ -s init stop
diff --git a/lib/syntax_tools/examples/merl/basic.erl b/lib/syntax_tools/examples/merl/basic.erl
new file mode 100644
index 0000000000..9030059d11
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/basic.erl
@@ -0,0 +1,77 @@
+%% ---------------------------------------------------------------------
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may
+%% not use this file except in compliance with the License. You may obtain
+%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @author Richard Carlsson <[email protected]>
+%% @copyright 2012 Richard Carlsson
+%% @doc Trivial Basic interpreter in Erlang
+
+-module(basic).
+
+-export([run/2]).
+
+-include_lib("eunit/include/eunit.hrl").
+
+-define(INTERPRETED, true).
+-include("basic_test.erl").
+
+run(N, Prog) ->
+ ets:new(var, [private, named_table]),
+ ets:new(line, [private, named_table, ordered_set]),
+ lists:foreach(fun (T) -> ets:insert(line, T) end, Prog),
+ goto(N).
+
+stop(N) ->
+ ets:delete(var),
+ ets:delete(line),
+ N.
+
+goto('$end_of_table') -> stop(0);
+goto(L) ->
+ L1 = ets:next(line, L),
+ %% user-supplied line numbers might not exist
+ case ets:lookup(line, L) of
+ [{_, X}] ->
+ stmt(X, L1);
+ _ ->
+ goto(L1)
+ end.
+
+stmt({print, S, As}, L) -> io:format(S, [expr(A) || A <- As]), goto(L);
+stmt({set, V, X}, L) -> ets:insert(var, {V, expr(X)}), goto(L);
+stmt({goto, X}, _L) -> goto(expr(X));
+stmt({stop, X}, _L) -> stop(expr(X));
+stmt({iff, X, A, B}, _L) ->
+ case expr(X) of
+ 0 -> goto(B);
+ _ -> goto(A)
+ end.
+
+expr(X) when is_number(X) ; is_list(X) ->
+ X;
+expr(X) when is_atom(X) ->
+ case ets:lookup(var, X) of
+ [] -> 0;
+ [{_,V}] -> V
+ end;
+expr({plus, X, Y}) ->
+ expr(X) + expr(Y);
+expr({equal, X, Y}) ->
+ bool(expr(X) == expr(Y));
+expr({gt, X, Y}) ->
+ bool(expr(X) > expr(Y));
+expr({knot, X}) ->
+ case expr(X) of
+ 0 -> 1;
+ _ -> 0
+ end.
+
+bool(true) -> 1;
+bool(false) -> 0.
diff --git a/lib/syntax_tools/examples/merl/basic_test.erl b/lib/syntax_tools/examples/merl/basic_test.erl
new file mode 100644
index 0000000000..ff35de6325
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/basic_test.erl
@@ -0,0 +1,77 @@
+%% ---------------------------------------------------------------------
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may
+%% not use this file except in compliance with the License. You may obtain
+%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @author Richard Carlsson <[email protected]>
+%% @copyright 2012 Richard Carlsson
+%% @doc Tests. For including in another module.
+
+%-module(basic_test).
+%-import(basic, run/1)
+
+-export([basic_fib/1]).
+
+-include_lib("eunit/include/eunit.hrl").
+
+basics_test_() ->
+ [?_assertEqual(42, run(1,[{1,{stop, 42}}])),
+ ?_assertEqual("hello", run(1,[{1,{stop,"hello"}}])),
+ ?_assertEqual(0, run(1,[{1,{print, "hello ~w", [42]}}])),
+ ?_assertEqual(5, run(1,[{1,{stop, {plus, 2, 3}}}])),
+ ?_assertEqual(5, run(1,[{1,{stop,{plus, 8, -3}}}])),
+ ?_assertEqual(0, run(1,[{1,{stop,{equal, 0, 1}}}])),
+ ?_assertEqual(1, run(1,[{1,{stop,{equal, 1, 1}}}])),
+ ?_assertEqual(0, run(1,[{1,{stop,{gt, 0, 1}}}])),
+ ?_assertEqual(0, run(1,[{1,{stop,{gt, 1, 1}}}])),
+ ?_assertEqual(1, run(1,[{1,{stop,{gt, 2, 1}}}])),
+ ?_assertEqual(0, run(1,[{1,{stop,{knot, 42}}}])),
+ ?_assertEqual(1, run(1,[{1,{stop,{knot, 0}}}])),
+ ?_assertEqual(42, run(1,[{1,{set, x, 42}}, {2,{stop,x}}])),
+ ?_assertEqual(17, run(1,[{1,{iff, 1, 2, 3}},
+ {2,{stop, 17}},
+ {3,{stop, 42}}])),
+ ?_assertEqual(42, run(1,[{1,{iff, 0, 2, 3}},
+ {2,{stop, 17}},
+ {3,{stop, 42}}])),
+ ?_assertEqual(17, run(1,[{1,{iff, 1, 2, 3}},
+ {2,{stop, 17}},
+ {3,{stop, -1}}])),
+ ?_assertEqual(42, run(1,[{1,{iff, 0, 2, 3}},
+ {2,{stop, -1}},
+ {3,{stop, 42}}]))
+
+
+ ].
+
+
+fib_test_() ->
+ [?_assertEqual(fib(N), basic_fib(N)) || N <- lists:seq(1,15)
+ ].
+
+
+fib(N) when N > 1 ->
+ fib(N-1) + fib(N-2);
+fib(_) ->
+ 1.
+
+basic_fib(N) ->
+ run(1,
+ [{1,{set,x,0}},
+ {2,{set,a,1}},
+ {3,{set,b,0}},
+ {10,{iff, {equal, x, N}, 20, 30}},
+ {20,{stop,a}},
+ {30,{print,"~w, ~w, ~w\n",[x,a,b]}},
+ {31,{set,t,a}},
+ {32,{set,a,{plus,a,b}}},
+ {33,{set,b,t}},
+ {34,{set,x,{plus,x,1}}},
+ {40,{goto,10}}
+ ]).
diff --git a/lib/syntax_tools/examples/merl/basicc.erl b/lib/syntax_tools/examples/merl/basicc.erl
new file mode 100644
index 0000000000..531ac51538
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/basicc.erl
@@ -0,0 +1,149 @@
+%% ---------------------------------------------------------------------
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may
+%% not use this file except in compliance with the License. You may obtain
+%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @author Richard Carlsson <[email protected]>
+%% @copyright 2012 Richard Carlsson
+%% @doc Basic compiler in Erlang.
+
+-module(basicc).
+
+-export([run/2, make_lines/1, bool/1]).
+
+-include_lib("eunit/include/eunit.hrl").
+
+-define(INTERPRETED, true).
+-include("basic_test.erl").
+
+-include("merl.hrl").
+
+run(N, Prog) ->
+ compile(Prog, tmp),
+ tmp:run(N, Prog).
+
+make_lines(Prog) ->
+ ets:new(line, [private, named_table, ordered_set]),
+ lists:foreach(fun ({L,_}) -> ets:insert(line, {L,label(L)}) end, Prog).
+
+compile(Prog, ModName) ->
+ make_lines(Prog),
+ Fs0 = lists:map(fun ({L, X}) ->
+ {true, label(L),
+ case stmt(X) of
+ {Stmt, false} ->
+ [?Q("() -> _@Stmt")];
+ {Stmt, true} ->
+ Next = case ets:next(line, L) of
+ '$end_of_table' ->
+ ?Q("stop(0)");
+ L1 ->
+ Label = label(L1),
+ ?Q("_@Label@()")
+ end,
+ [?Q("() -> _@Stmt, _@Next")]
+ end}
+ end, Prog),
+ ets:delete(line),
+ Run = ?Q(["(N, Prog) ->",
+ " ets:new(var, [private, named_table]),",
+ " basicc:make_lines(Prog),",
+ " goto(N)"
+ ]),
+ Stop = ?Q(["(R) ->",
+ " ets:delete(var),",
+ " ets:delete(line),",
+ " R"
+ ]),
+ Goto = ?Q(["(L) ->",
+ " case ets:lookup(line, L) of",
+ " [{_, X}] -> apply(tmp, X, []);",
+ " _ ->",
+ " case ets:next(line, L) of",
+ " '$end_of_table' -> stop(0);",
+ " L1 -> goto(L1)",
+ " end",
+ " end"]),
+ Fs = [{true, run, [Run]},
+ {false, stop, [Stop]},
+ {true, goto, [Goto]}
+ | Fs0],
+ Forms = merl_build:module_forms(
+ lists:foldl(fun ({X, Name, Cs}, S) ->
+ merl_build:add_function(X, Name, Cs, S)
+ end,
+ merl_build:init_module(ModName),
+ Fs)),
+ %% %% Write source to file for debugging
+ %% file:write_file(lists:concat([ModName, "_gen.erl"]),
+ %% erl_prettypr:format(erl_syntax:form_list(Forms),
+ %% [{paper,160},{ribbon,80}])),
+ merl:compile_and_load(Forms, [verbose]).
+
+label(L) ->
+ list_to_atom("label_" ++ integer_to_list(L)).
+
+stmt({print, S, As}) ->
+ Exprs = [expr(A) || A <- As],
+ {[?Q(["io:format(_@S@, [_@Exprs])"])], true};
+stmt({set, V, X}) ->
+ Expr = expr(X),
+ {[?Q(["ets:insert(var, {_@V@, _@Expr})"])], true};
+stmt({goto, X}) ->
+ {[jump(X)], false};
+stmt({stop, X}) ->
+ Expr = expr(X),
+ {[?Q(["stop(_@Expr)"])], false};
+stmt({iff, X, A, B}) ->
+ Cond = expr(X),
+ True = jump(A),
+ False = jump(B),
+ {?Q(["case _@Cond of",
+ " 0 -> _@False;",
+ " _ -> _@True",
+ "end"]),
+ false}.
+
+jump(X) ->
+ case ets:lookup(line, X) of
+ [{_, F}] ->
+ ?Q(["_@F@()"]);
+ true ->
+ Expr = expr(X),
+ [?Q(["goto(_@Expr)"])]
+ end.
+
+expr(X) when is_number(X) ; is_list(X) ->
+ ?Q("_@X@");
+expr(X) when is_atom(X) ->
+ ?Q(["case ets:lookup(var, _@X@) of",
+ " [] -> 0;",
+ " [{_,V}] -> V",
+ "end"]);
+expr({plus, X, Y}) ->
+ ExprX = expr(X),
+ ExprY = expr(Y),
+ ?Q("_@ExprX + _@ExprY");
+expr({equal, X, Y}) ->
+ ExprX = expr(X),
+ ExprY = expr(Y),
+ ?Q("basicc:bool(_@ExprX == _@ExprY)");
+expr({gt, X, Y}) ->
+ ExprX = expr(X),
+ ExprY = expr(Y),
+ ?Q("basicc:bool(_@ExprX > _@ExprY)");
+expr({knot, X}) ->
+ Expr = expr(X),
+ ?Q(["case _@Expr of",
+ " 0 -> 1;",
+ " _ -> 0",
+ "end"]).
+
+bool(true) -> 1;
+bool(false) -> 0.
diff --git a/lib/syntax_tools/examples/merl/lisp.erl b/lib/syntax_tools/examples/merl/lisp.erl
new file mode 100644
index 0000000000..371dc6b261
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/lisp.erl
@@ -0,0 +1,160 @@
+%% ---------------------------------------------------------------------
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may
+%% not use this file except in compliance with the License. You may obtain
+%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @author Richard Carlsson <[email protected]>
+%% @copyright 2012 Richard Carlsson
+%% @doc Trivial Lisp interpreter in Erlang.
+
+-module(lisp).
+
+-export([eval/1]).
+
+-export([init/0, equal/2, gt/2, knot/1]).
+
+-record(st, {env}).
+
+-define(INTERPRETED, true).
+-include("lisp_test.erl").
+
+eval(P) ->
+ {X, _} = eval(P, init()),
+ X.
+
+init() ->
+ Env = [{print, {builtin, fun do_print/2}}
+ ,{list, {builtin, fun do_list/2}}
+ ,{apply, {builtin, fun do_apply/2}}
+ ,{plus, {builtin, fun do_plus/2}}
+ ,{equal, {builtin, fun do_equal/2}}
+ ,{gt, {builtin, fun do_gt/2}}
+ ,{knot, {builtin, fun do_knot/2}}
+ ,{y, y()}
+ ],
+ #st{env=dict:from_list(Env)}.
+
+eval([lambda, Ps, B], #st{env=E}=St) when is_list(Ps) ->
+ case lists:all(fun is_atom/1, Ps) andalso
+ (length(Ps) =:= length(lists:usort(Ps))) of
+ true -> {{lambda, Ps, B, E}, St};
+ false -> throw(bad_lambda)
+ end;
+eval([lambda | _], _) ->
+ throw(bad_lambda);
+eval([def, A, V, B], #st{env=E0}=St) when is_atom(A) ->
+ {V1, St1} = eval(V, St),
+ E1 = bind(A, V1, E0),
+ {X, St2} = eval(B, St1#st{env=E1}),
+ {X, St2#st{env=E0}};
+eval([def | _], _) ->
+ throw(bad_def);
+eval([quote, A], St) ->
+ {A, St};
+eval([quote | _], _) ->
+ throw(bad_quote);
+eval([iff, X, A, B], St) ->
+ case eval(X, St) of
+ {[], St1} -> eval(B, St1);
+ {_, St1} -> eval(A, St1)
+ end;
+eval([do], _St0) ->
+ throw(bad_do);
+eval([do | As], St0) ->
+ lists:foldl(fun (X, {_,St}) -> eval(X, St) end, {[],St0}, As);
+eval([_|_]=L, St) ->
+ {[F | As], St1} = lists:mapfoldl(fun eval/2, St, L),
+ call(F, As, St1);
+eval(A, St) when is_atom(A) ->
+ {deref(A, St), St};
+eval(C, St) ->
+ {C, St}.
+
+%% UTILITY FUNCTIONS
+
+deref(A, #st{env=E}) ->
+ case dict:find(A, E) of
+ {ok, V} -> V;
+ error -> throw({undefined, A})
+ end.
+
+bind(A, V, E) ->
+ dict:store(A, V, E).
+
+bind_args([P | Ps], [A | As], E) ->
+ bind_args(Ps, As, dict:store(P, A, E));
+bind_args([], [], E) ->
+ E;
+bind_args(_, _, _) ->
+ throw(bad_arity).
+
+call({lambda, Ps, B, E}, As, #st{env=E0}=St) ->
+ {X, St1} = eval(B, St#st{env=bind_args(Ps, As, E)}),
+ {X, St1#st{env=E0}};
+call({builtin, F}, As, St) ->
+ F(As, St);
+call(X, _, _) ->
+ throw({bad_fun, X}).
+
+bool(true) -> 1;
+bool(false) -> [].
+
+%% BUILTINS
+
+y() ->
+ {Y, _} = eval([lambda, [f],
+ [[lambda, [x], [f, [lambda, [y], [[x, x], y]]]],
+ [lambda, [x], [f, [lambda, [y], [[x, x], y]]]]]],
+ #st{env=dict:new()}),
+ Y.
+
+do_print([S | Xs], St) ->
+ io:format(S, Xs),
+ {[], St};
+do_print(_, _) ->
+ throw(bad_print).
+
+do_list(As, St) ->
+ {As, St}.
+
+do_apply([F, As], St) ->
+ call(F, As, St);
+do_apply(_, _) ->
+ throw(bad_apply).
+
+do_plus([X, Y], St) when is_number(X), is_number(Y) ->
+ {X + Y, St};
+do_plus(As, _) ->
+ throw({bad_plus, As}).
+
+do_equal([X, Y], St) ->
+ {equal(X, Y), St};
+do_equal(As, _) ->
+ throw({bad_equal, As}).
+
+equal(X, Y) ->
+ bool(X =:= Y).
+
+do_gt([X, Y], St) ->
+ {gt(X, Y), St};
+do_gt(As, _) ->
+ throw({bad_gt, As}).
+
+gt(X, Y) ->
+ bool(X > Y).
+
+do_knot([X], St) ->
+ {knot(X), St};
+do_knot(As, _) ->
+ throw({bad_gt, As}).
+
+knot([]) ->
+ 1;
+knot(_) ->
+ [].
diff --git a/lib/syntax_tools/examples/merl/lisp_test.erl b/lib/syntax_tools/examples/merl/lisp_test.erl
new file mode 100644
index 0000000000..cab8134b8f
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/lisp_test.erl
@@ -0,0 +1,98 @@
+%% ---------------------------------------------------------------------
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may
+%% not use this file except in compliance with the License. You may obtain
+%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @author Richard Carlsson <[email protected]>
+%% @copyright 2012 Richard Carlsson
+%% @doc Tests. For including in another module.
+
+%-module(lisp_test).
+%-import(lisp, eval/1)
+
+-export([fib/1, lisp_fib/1]).
+
+-include_lib("eunit/include/eunit.hrl").
+
+basics_test_() ->
+ [?_assertEqual(42, eval(42)),
+ ?_assertEqual("hello", eval([quote, "hello"])),
+ ?_assertEqual(print, eval([quote, print])),
+ ?_assertMatch([17,[1,2],42], eval([list,17,[list,1,2],42])),
+ ?_assertEqual([], eval([print, [quote, "hello ~w"], [list, 42]])),
+ ?_assertEqual(5, eval([plus, 2, 3])),
+ ?_assertEqual(5, eval([plus, 8, -3])),
+ ?_assertEqual([], eval([equal, 0, 1])),
+ ?_assertEqual(1, eval([equal, 1, 1])),
+ ?_assertEqual([], eval([gt, 0, 1])),
+ ?_assertEqual([], eval([gt, 1, 1])),
+ ?_assertEqual(1, eval([gt, 2, 1])),
+ ?_assertEqual([], eval([knot, 42])),
+ ?_assertEqual(1, eval([knot, []])),
+ ?_assertEqual(42, eval([do, 17, 42])),
+ ?_assertEqual([], eval([apply, print, [quote, ["~p", [42]]]])),
+ ?_assertEqual(42, eval([iff, [], 17, 42])),
+ ?_assertEqual(17, eval([iff, 1, 17, 42])),
+ ?_assertEqual(42, eval([iff, [], [apply], 42])),
+ ?_assertEqual(17, eval([iff, 1, 17, [apply]])),
+ ?_assertEqual(17, eval([def, foo, 17, foo])),
+ ?_assertEqual(17, eval([def, bar, 42, [def, foo, 17, foo]])),
+ ?_assertEqual(42, eval([def, bar, 42, [def, foo, 17, bar]])),
+ ?_assertEqual(17, eval([def, foo, 42, [def, foo, 17, foo]]))
+ ].
+
+-ifdef(INTERPRETED).
+interpreter_basics_test_() ->
+ [?_assertThrow({undefined, foo}, eval(foo)),
+ ?_assertMatch({builtin,_}, eval(print)),
+ ?_assertThrow(bad_do, eval([do])),
+ ?_assertThrow(bad_apply, eval([apply])),
+ ?_assertThrow({undefined, foo}, eval([def, bar, 17, foo]))
+ ].
+
+interpreter_lambda_test_() ->
+ [?_assertMatch({lambda,_,_,_}, eval([lambda, [], 42])),
+ ?_assertMatch({lambda,_,_,_}, eval([lambda, [x], x])),
+ ?_assertMatch({lambda,_,_,_}, eval([lambda, [x,y], 42]))
+ ].
+-endif.
+
+lambda_test_() ->
+ [?_assertThrow(bad_lambda, eval([lambda])),
+ ?_assertThrow(bad_lambda, eval([lambda, []])),
+ ?_assertThrow(bad_lambda, eval([lambda, [], 17, 42])),
+ ?_assertThrow(bad_lambda, eval([lambda, 17, 42])),
+ ?_assertThrow(bad_lambda, eval([lambda, [17], 42])),
+ ?_assertThrow(bad_lambda, eval([lambda, [foo, foo], 42])),
+ ?_assertEqual(42, eval([[lambda, [x], x], 42])),
+ ?_assertEqual([42, 17], eval([[lambda, [x], [list, x, 17]], 42])),
+ ?_assertEqual([42, 17], eval([def, f, [def, y, 42,
+ [lambda, [x], [list, y, x]]],
+ [f, 17]]))
+ ].
+
+fib_test_() ->
+ [?_assertEqual(fib(N), lisp_fib(N)) || N <- lists:seq(1,15)
+ ].
+
+
+fib(N) when N > 1 ->
+ fib(N-1) + fib(N-2);
+fib(_) ->
+ 1.
+
+lisp_fib(N) ->
+ eval([def, fib,
+ [y, [lambda, [f], [lambda, [x],
+ [iff, [gt, x, 1],
+ [plus, [f, [plus,x,-1]], [f, [plus,x,-2]]],
+ 1]
+ ]]],
+ [fib, N]
+ ]).
diff --git a/lib/syntax_tools/examples/merl/lispc.erl b/lib/syntax_tools/examples/merl/lispc.erl
new file mode 100644
index 0000000000..97072cdab7
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/lispc.erl
@@ -0,0 +1,102 @@
+%% ---------------------------------------------------------------------
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may
+%% not use this file except in compliance with the License. You may obtain
+%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @author Richard Carlsson <[email protected]>
+%% @copyright 2012 Richard Carlsson
+%% @doc Lisp compiler in Erlang.
+
+-module(lispc).
+
+-export([eval/1]).
+
+-record(st, {}).
+
+-include("lisp_test.erl").
+
+-include("merl.hrl").
+
+eval(Lisp) ->
+ compile(Lisp, tmp),
+ tmp:eval().
+
+compile(Lisp, ModName) ->
+ {Code, _} = gen(Lisp, #st{}),
+ Main = ?Q(["() ->",
+ " __print = fun (S, Xs) -> io:format(S,Xs), [] end,",
+ " __apply = fun erlang:apply/2,",
+ " __plus = fun erlang:'+'/2,",
+ " __equal = fun lisp:equal/2,",
+ " __gt = fun lisp:gt/2,",
+ " __knot = fun lisp:knot/1,",
+ " __y = fun (F) ->",
+ " (fun (X) -> F(fun (Y) -> (X(X))(Y) end) end)",
+ " (fun (X) -> F(fun (Y) -> (X(X))(Y) end) end)",
+ " end,",
+ " _@Code"]),
+ Forms = merl_build:module_forms(
+ merl_build:add_function(true, eval, [Main],
+ merl_build:init_module(ModName))),
+ %% %% Write source to file for debugging
+ %% file:write_file(lists:concat([ModName, "_gen.erl"]),
+ %% erl_prettypr:format(erl_syntax:form_list(Forms),
+ %% [{paper,160},{ribbon,80}])),
+ merl:compile_and_load(Forms, [verbose]).
+
+var(Atom) ->
+ merl:var(list_to_atom("__" ++ atom_to_list(Atom))).
+
+gen([lambda, Ps, B], St) when is_list(Ps) ->
+ case lists:all(fun is_atom/1, Ps) andalso
+ (length(Ps) =:= length(lists:usort(Ps))) of
+ true ->
+ Vars = [var(P) || P <- Ps],
+ {Body, St1} = gen(B, St),
+ {?Q("fun (_@Vars) -> _@Body end"), St1};
+ false ->
+ throw(bad_lambda)
+ end;
+gen([lambda | _], _) ->
+ throw(bad_lambda);
+gen([def, A, V, B], St) when is_atom(A) ->
+ Var = var(A),
+ {Val, St1} = gen(V, St),
+ {Body, St2} = gen(B, St1),
+ {?Q("(fun (_@Var) -> _@Body end)(_@Val)"), St2};
+gen([def | _], _) ->
+ throw(bad_def);
+gen([quote, A], St) ->
+ {merl:term(A), St};
+gen([quote | _], _) ->
+ throw(bad_quote);
+gen([iff, X, A, B], St) ->
+ {Cond, St1} = gen(X, St),
+ {True, St2} = gen(A, St1),
+ {False, St3} = gen(B, St2),
+ {?Q(["case _@Cond of",
+ " [] -> _@False;",
+ " _ -> _@True",
+ "end"]),
+ St3};
+gen([do], _) ->
+ throw(bad_do);
+gen([do | As], St0) ->
+ {Body, St1} = lists:mapfoldl(fun gen/2, St0, As),
+ {?Q("begin _@Body end"), St1};
+gen([list | As], St0) ->
+ {Elem, St1} = lists:mapfoldl(fun gen/2, St0, As),
+ {?Q("[ _@Elem ]"), St1};
+gen([_|_]=L, St) ->
+ {[F | As], St1} = lists:mapfoldl(fun gen/2, St, L),
+ {?Q("((_@F)(_@As))"), St1};
+gen(A, St) when is_atom(A) ->
+ {var(A), St};
+gen(C, St) ->
+ {merl:term(C), St}.
diff --git a/lib/syntax_tools/examples/merl/merl_build.erl b/lib/syntax_tools/examples/merl/merl_build.erl
new file mode 100644
index 0000000000..c539f8e2af
--- /dev/null
+++ b/lib/syntax_tools/examples/merl/merl_build.erl
@@ -0,0 +1,104 @@
+%% ---------------------------------------------------------------------
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may
+%% not use this file except in compliance with the License. You may obtain
+%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @author Richard Carlsson <[email protected]>
+%% @copyright 2012 Richard Carlsson
+%% @doc Making it simple to build a module with merl
+
+-module(merl_build).
+
+-export([init_module/1, module_forms/1, add_function/4, add_record/3,
+ add_import/3, add_attribute/3, set_file/2]).
+
+-import(merl, [term/1]).
+
+-include("merl.hrl").
+
+-type filename() :: string().
+
+-record(module, { name :: atom()
+ , file :: filename()
+ , exports=[] :: [{atom(), integer()}]
+ , imports=[] :: [{atom(), [{atom(), integer()}]}]
+ , attributes=[] :: [{filename(), atom(), [term()]}]
+ , records=[] :: [{filename(), atom(),
+ [{atom(), merl:tree()}]}]
+ , functions=[] :: [{filename(), atom(), [merl:tree()]}]
+ }).
+
+%% TODO: init module from a list of forms (from various sources)
+
+%% @doc Create a new module representation, using the given module name.
+init_module(Name) when is_atom(Name) ->
+ %% use the module name as the default file name - better than nothing
+ #module{name=Name, file=atom_to_list(Name)}.
+
+%% @doc Get the list of syntax tree forms for a module representation. This can
+%% be passed to compile/2.
+module_forms(#module{name=Name,
+ exports=Xs,
+ imports=Is,
+ records=Rs,
+ attributes=As,
+ functions=Fs})
+ when is_atom(Name), Name =/= undefined ->
+ Module = ?Q("-module('@Name@')."),
+ Exported = [erl_syntax:arity_qualifier(term(N), term(A))
+ || {N,A} <- ordsets:from_list(Xs)],
+ Export = ?Q("-export(['@_Exported'/1])."),
+ Imports = [?Q("-import('@M@', ['@_NAs'/1]).")
+ || {M, Ns} <- Is,
+ NAs <- [[erl_syntax:arity_qualifier(term(N), term(A))
+ || {N,A} <- ordsets:from_list(Ns)]]
+ ],
+ Attrs = [?Q("-file(\"'@File@\",1). -'@N@'('@T@').")
+ || {File, N, T} <- lists:reverse(As)],
+ Records = [?Q("-file(\"'@File@\",1). -record('@N@',{'@_RFs'=[]}).")
+ || {File, N, Es} <- lists:reverse(Rs),
+ RFs <- [[erl_syntax:record_field(term(F), V)
+ || {F,V} <- Es]]
+ ],
+ Functions = [?Q("-file(\"'@File@\",1). '@_F'() -> [].")
+ || {File, N, Cs} <- lists:reverse(Fs),
+ F <- [erl_syntax:function(term(N), Cs)]],
+ lists:flatten([Module, Export, Imports, Attrs, Records, Functions]).
+
+%% @doc Set the source file name for all subsequently added functions,
+%% records, and attributes.
+set_file(Filename, #module{}=M) ->
+ M#module{file=filename:flatten(Filename)}.
+
+%% @doc Add a function to a module representation.
+add_function(Exported, Name, Clauses,
+ #module{file=File, exports=Xs, functions=Fs}=M)
+ when is_boolean(Exported), is_atom(Name), Clauses =/= [] ->
+ Arity = length(erl_syntax:clause_patterns(hd(Clauses))),
+ Xs1 = case Exported of
+ true -> [{Name,Arity} | Xs];
+ false -> Xs
+ end,
+ M#module{exports=Xs1, functions=[{File, Name, Clauses} | Fs]}.
+
+%% @doc Add a record declaration to a module representation.
+add_record(Name, Fields, #module{file=File, records=Rs}=M)
+ when is_atom(Name) ->
+ M#module{records=[{File, Name, Fields} | Rs]}.
+
+%% @doc Add a "wild" attribute, such as `-compile(Opts)' to a module
+%% representation. Note that such attributes can only have a single argument.
+add_attribute(Name, Term, #module{file=File, attributes=As}=M)
+ when is_atom(Name) ->
+ M#module{attributes=[{File, Name, Term} | As]}.
+
+%% @doc Add an import declaration to a module representation.
+add_import(From, Names, #module{imports=Is}=M)
+ when is_atom(From), is_list(Names) ->
+ M#module{imports=[{From, Names} | Is]}.