diff options
-rw-r--r-- | Spear/Step.hs | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/Spear/Step.hs b/Spear/Step.hs index e767166..a860247 100644 --- a/Spear/Step.hs +++ b/Spear/Step.hs | |||
@@ -112,9 +112,11 @@ swhen expectedEvent step = Step $ \elapsed dt state maybeEvent a -> | |||
112 | in (a', swhen expectedEvent step') | 112 | in (a', swhen expectedEvent step') |
113 | else (a, swhen expectedEvent step) | 113 | else (a, swhen expectedEvent step) |
114 | 114 | ||
115 | -- | Construct a step that switches between two steps based on input. | 115 | -- | Construct a step that switches between two steps based on input events. |
116 | -- | 116 | -- |
117 | -- The initial step is the first one. | 117 | -- The current step runs with every 'runStep' even when there are no new events. |
118 | -- | ||
119 | -- The initial step is the identity, 'sid'. | ||
118 | switch :: | 120 | switch :: |
119 | Eq e => | 121 | Eq e => |
120 | e -> | 122 | e -> |
@@ -122,16 +124,8 @@ switch :: | |||
122 | e -> | 124 | e -> |
123 | Step s (Maybe e) a a -> | 125 | Step s (Maybe e) a a -> |
124 | Step s (Maybe e) a a | 126 | Step s (Maybe e) a a |
125 | switch flag1 s1 flag2 s2 = switch' s1 flag1 s1 flag2 s2 | 127 | switch = switch' sid |
126 | 128 | ||
127 | switch' :: | ||
128 | Eq e => | ||
129 | Step s (Maybe e) a a -> | ||
130 | e -> | ||
131 | Step s (Maybe e) a a -> | ||
132 | e -> | ||
133 | Step s (Maybe e) a a -> | ||
134 | Step s (Maybe e) a a | ||
135 | switch' cur flag1 s1 flag2 s2 = Step $ \elapsed dt g e a -> | 129 | switch' cur flag1 s1 flag2 s2 = Step $ \elapsed dt g e a -> |
136 | case e of | 130 | case e of |
137 | Nothing -> | 131 | Nothing -> |
@@ -141,11 +135,15 @@ switch' cur flag1 s1 flag2 s2 = Step $ \elapsed dt g e a -> | |||
141 | let next | 135 | let next |
142 | | e' == flag1 = s1 | 136 | | e' == flag1 = s1 |
143 | | e' == flag2 = s2 | 137 | | e' == flag2 = s2 |
144 | | otherwise = cur | 138 | | otherwise = cur |
145 | (a', s') = runStep next elapsed dt g e a | 139 | (a', s') = runStep next elapsed dt g e a |
146 | in (a', switch' s' flag1 s1 flag2 s2) | 140 | in (a', switch' s' flag1 s1 flag2 s2) |
147 | 141 | ||
148 | -- | Construct a step that switches among multiple steps based on input. | 142 | -- | Construct a step that switches among multiple steps based on input events. |
143 | -- | ||
144 | -- The current step runs with every 'runStep' even when there are no new events. | ||
145 | -- | ||
146 | -- The initial step is the identity, 'sid'. | ||
149 | multiSwitch :: (Eq e, Ord e) => [(e, Step s (Maybe e) a a)] -> Step s (Maybe e) a a | 147 | multiSwitch :: (Eq e, Ord e) => [(e, Step s (Maybe e) a a)] -> Step s (Maybe e) a a |
150 | multiSwitch xs = multiSwitch' Nothing sid (Map.fromList xs) | 148 | multiSwitch xs = multiSwitch' Nothing sid (Map.fromList xs) |
151 | 149 | ||