From 0a59d8631e2acb20601e72c6f79d7ce193633844 Mon Sep 17 00:00:00 2001
From: olpc user <olpc@xo-5d-f7-86.localdomain>
Date: Sat, 14 Dec 2019 11:48:23 -0800
Subject: missing changes

---
 starts/meaning-vm/level-1/sugar.cpp    | 1 +
 starts/meaning-vm/level-2/concepts.hpp | 3 +++
 starts/meaning-vm/level-2/funcs.cpp    | 9 +++++++--
 starts/meaning-vm/level-2/sugar.hpp    | 2 ++
 4 files changed, 13 insertions(+), 2 deletions(-)

(limited to 'starts/meaning-vm')

diff --git a/starts/meaning-vm/level-1/sugar.cpp b/starts/meaning-vm/level-1/sugar.cpp
index accad6c..025c68e 100644
--- a/starts/meaning-vm/level-1/sugar.cpp
+++ b/starts/meaning-vm/level-1/sugar.cpp
@@ -20,6 +20,7 @@ ref a(ref group)
 }
 ref a(ref group, ref name)
 {
+	if (name == nothing) { return a(group); }
 	if (!name.isa(group)) {
 		name.link(is, group);
 	}
diff --git a/starts/meaning-vm/level-2/concepts.hpp b/starts/meaning-vm/level-2/concepts.hpp
index 3a6ac6b..8e9c145 100644
--- a/starts/meaning-vm/level-2/concepts.hpp
+++ b/starts/meaning-vm/level-2/concepts.hpp
@@ -7,11 +7,14 @@ namespace level2 {
 
 namespace concepts {
 
+using level1::concepts::nothing;
+
 static ref context("context");
 static ref habit("habit");
 static ref next("next");
 static ref positional("positional");
 static ref argument("argument");
+static ref result("result");
 
 }
 
diff --git a/starts/meaning-vm/level-2/funcs.cpp b/starts/meaning-vm/level-2/funcs.cpp
index a8835f4..11b3184 100644
--- a/starts/meaning-vm/level-2/funcs.cpp
+++ b/starts/meaning-vm/level-2/funcs.cpp
@@ -46,13 +46,18 @@ ref dohabit(ref habit, std::initializer_list<ref> args)
 	if (posarg.linked(next-positional-argument)) {
 		throw std::invalid_argument("wrong number of arguments to habit");
 	}
-	ref ret = habit.fun<ref>()(ref::context());
+	habit.fun<ref>()(ref::context());
 	posarg = habit;
 	while (posarg.linked(next-positional-argument)) {
 		posarg = posarg[next-positional-argument];
 		ref::context().unlink(posarg[argument]);
 	}
-	return ret;
+	if (ref::context().linked(result)) {
+		ref ret = ref::context().get(result);
+		ref::context().unlink(result, ret);
+		return ret;
+	}
+	return nothing;
 }
 
 }
diff --git a/starts/meaning-vm/level-2/sugar.hpp b/starts/meaning-vm/level-2/sugar.hpp
index bff945b..5b3b150 100644
--- a/starts/meaning-vm/level-2/sugar.hpp
+++ b/starts/meaning-vm/level-2/sugar.hpp
@@ -32,8 +32,10 @@
 			usleep(delay); \
 		} \
 		ref self = name; (void)self; \
+		ref result("nothing"); (void)result; \
 		_macro_call(_macro_for_each_parens, _macro_habit_set_posarg, _macro_habit_set_posarg _macro_comma_remove_parens(argnametoklist)); \
 		__VA_ARGS__ \
+		if (result != ref("nothing")) { ctx.link(ref("result"), result); }
 	});
 	#define _macro_habit_argnameref(name, tok) \
 		ref(#name)
-- 
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