Wrap ImGui::BeginChild and EndChild (#21)

Main.hs

@@ -78,11 +78,15 @@ loop w checked color slider = do
 
   progressBar 0.314 (Just "Pi")
 
+  beginChild "Child"
+
   beginCombo "Label" "Preview" >>= whenTrue do
     selectable "Testing 1"
     selectable "Testing 2"
     endCombo
 
+  endChild
+
   plotHistogram "A histogram" [ 10, 10, 20, 30, 90 ]
 
   colorPicker3 "Test" color

src/DearImGui.hs

@@ -43,6 +43,10 @@ module DearImGui
   , begin
   , end
 
+    -- * Child Windows
+  , beginChild
+  , endChild
+
     -- * Cursor/Layout
   , separator
   , sameLine
@@ -276,6 +280,19 @@ end = liftIO do
   [C.exp| void { ImGui::End(); } |]
 
 
+-- | Wraps @ImGui::BeginChild()@.
+beginChild :: MonadIO m => String -> m Bool
+beginChild name = liftIO do
+  withCString name \namePtr ->
+    (0 /=) <$> [C.exp| bool { ImGui::BeginChild($(char* namePtr)) } |]
+
+
+-- | Wraps @ImGui::EndChild()@.
+endChild :: MonadIO m => m ()
+endChild = liftIO do
+  [C.exp| void { ImGui::EndChild(); } |]
+
+
 -- | Separator, generally horizontal. inside a menu bar or in horizontal layout
 -- mode, this becomes a vertical separator.
 --