Connect nodes with edges.

gui/Main.hs

@@ -405,7 +405,7 @@ clickOnNode ::
   (Double, Double) -> -- Click position where (0,0) is top left of element
   AppState ->
   AppState
-clickOnNode elemId relativePosition oldState@AppState {_asMovingNode, _asHistory, _asElements} =
+clickOnNode elemId relativePosition oldState@AppState {_asMovingNode, _asHistory, _asElements, _asCurrentEdge, _asEdges} =
   let portClicked = case IntMap.lookup (_unElemId elemId) _asElements of
         Nothing -> Nothing
         Just element ->
@@ -413,7 +413,13 @@ clickOnNode elemId relativePosition oldState@AppState {_asMovingNode, _asHistory
    in case _asMovingNode of
         Nothing -> case portClicked of
           Nothing -> oldState {_asMovingNode = Just elemId}
-          _ -> oldState
+          Just _port -> case _asCurrentEdge of
+            Nothing -> oldState {_asCurrentEdge = Just elemId}
+            Just edgeElemId ->
+              oldState
+                { _asEdges = (edgeElemId, elemId) : _asEdges,
+                  _asCurrentEdge = Nothing
+                }
         Just _ ->
           addHistoryEvent MovedNode $
             oldState {_asMovingNode = Nothing}

todo.md

@@ -9,12 +9,21 @@
 * Add wiki pages discussing: Why a visual language?, History of Glance, How to contribute, Code guide [code style, ...], etc..
 
 ## GUI Todo Later
-* Connect nodes with lines
+* Connect edges to specific ports
+* Select areas by clicking the vertices of the selection area.
+* Have a way to delete nodes and edges
 * Display the undo state in the app [Bug #14](https://github.com/rgleichman/glance/issues/14)
 * Scale based on mouse position
+* Add edge creation to history.
 * Extract out GUI interface code (GTK and GDK) into a module.
 * Refactor to make code extensible (e.g. records of functions instead of enums)
 * Click a button that shows an image of the mouse and keyboard controls in a new window.
+* Consider a way to keep the currentEdge after creating an edge. May
+  be useful where a variable is used mulitple times (e.g. a big struct
+  parameter).
+* Create functions by connecting a second edge to an apply argument
+  port and then selecting the second output (or maybe just the select
+  the output of the function and connect the function up later?)
 
 ### Testing todos
 * Fix the arrowheads being too big for SyntaxGraph drawings.