Add basics of properly handling ports

compiler/Generate/JavaScript.hs

@@ -299,7 +299,8 @@ generate unsafeModule =
                , [ IfSingleStmt () thisModule (ReturnStmt () (Just thisModule)) ]
                , [ internalImports (List.intercalate "." (names modul)) ]
                , concatMap jsImport (imports modul)
-               , concatMap jsPort (ports modul)
+               , checkInPorts (ports modul)
+               , map jsPort (ports modul)
                , [ assign ["_op"] (ObjectLit () []) ]
                , concat $ evalState (mapM definition . fst . SD.flattenLets [] $ program modul) 0
                , [ jsExports ]
@@ -331,10 +332,15 @@ generate unsafeModule =
 
     addId js = InfixExpr () OpAdd (string (js++"_")) (obj "_elm.id")
 
+    checkInPorts ports =
+        [ ExprStmt () $ obj "_N.checkPorts" `call` [ref "$moduleName", names] ]
+        where
+          names = ArrayLit () [ string name | (name, _, Nothing) <- ports ]
+
     jsPort (name, _, maybe) =
         case maybe of
-          Nothing -> error "in-ports are not defined yet"
-          Just expr -> error "out-ports are not defined yet"
+          Nothing -> assign [name] $ dotSep ["_elm","ports_in",name]
+          Just expr -> assign ["_elm","ports_out",name] $ evalState (expression expr) 0
 
 binop span op e1 e2 =
     case op of

compiler/Transform/Optimize.hs

@@ -19,7 +19,7 @@ class Simplify a where
 
 instance Simplify (Declaration t v) where
   simp (Definition def) = Definition (simp def)
-  simp (ImportEvent js b elm t) = ImportEvent js (simp b) elm t
+  simp (Port name tipe maybe) = Port name tipe (simp `fmap` maybe)
   simp stmt = stmt
 
 instance Simplify (Def t v) where

libraries/Native/Utils.js

@@ -207,6 +207,30 @@ Elm.Native.Utils.make = function(elm) {
         return Tuple2(posx, posy);
     }
 
+    function checkPorts(moduleName, ports) {
+        var expected = {};
+        for (var i = ports.length; i--; ) {
+            expected[ports[i]] = 1;
+        }
+        for (var key in elm.ports_in) {
+            expected[key] = expected[key] || 0;
+            expected[key] -= 1;
+        }
+        var missing = [];
+        var extra = [];
+        for (var key in expected) {
+            var result = expected[key];
+            if (result > 0) missing.push(key);
+            if (result < 0) extra.push(key);
+        }
+        if (missing.length > 0) {
+            throw new Error("Module " + moduleName + " requires inputs for these ports: " + missing.join(', '));
+        }
+        if (extra.length > 0) {
+            throw new Error("Module " + moduleName + " has been given ports that do not exist: " + extra.join(', '));
+        }
+    }
+
     return elm.Native.Utils.values = {
         eq:eq,
         cmp:cmp,
@@ -226,6 +250,7 @@ Elm.Native.Utils.make = function(elm) {
         mod : F2(mod),
         htmlHeight: F2(htmlHeight),
         getXY: getXY,
-        toFloat: function(x) { return +x; }
+        toFloat: function(x) { return +x; },
+        checkPorts: checkPorts
     };
 };

runtime/Init.js

@@ -2,7 +2,7 @@
 (function() {
 'use strict';
 
-Elm.fullscreen = function(module) {
+Elm.fullscreen = function(module, ports) {
     var style = document.createElement('style');
     style.type = 'text/css';
     style.innerHTML = "html,head,body { padding:0; margin:0; }" +
@@ -10,24 +10,24 @@ Elm.fullscreen = function(module) {
     document.head.appendChild(style);
     var container = document.createElement('div');
     document.body.appendChild(container);
-    return init(ElmRuntime.Display.FULLSCREEN, container, module);
+    return init(ElmRuntime.Display.FULLSCREEN, container, module, ports);
 };
 
-Elm.embed = function(module, container) {
+Elm.embed = function(module, container, ports) {
     var tag = container.tagName;
     if (tag !== 'DIV') {
         throw new Error('Elm.node must be given a DIV, not a ' + tag + '.');
     } else if (container.hasChildNodes()) {
         throw new Error('Elm.node must be given an empty DIV. No children allowed!');
     }
-    return init(ElmRuntime.Display.COMPONENT, container, module);
+    return init(ElmRuntime.Display.COMPONENT, container, module, ports);
 };
 
-Elm.worker = function(module) {
-    return init(ElmRuntime.Display.NONE, {}, module);
+Elm.worker = function(module, ports) {
+    return init(ElmRuntime.Display.NONE, {}, module, ports);
 };
 
-function init(display, container, module, moduleToReplace) {
+function init(display, container, module, moduleToReplace, ports) {
   // defining state needed for an instance of the Elm RTS
   var inputs = [];
 
@@ -67,7 +67,8 @@ function init(display, container, module, moduleToReplace) {
       display:display,
       id:ElmRuntime.guid(),
       addListener:addListener,
-      inputs:inputs
+      inputs:inputs,
+      ports_in:ports
   };
 
   // Set up methods to communicate with Elm program from JS.
@@ -123,7 +124,7 @@ function init(display, container, module, moduleToReplace) {
   }
 
   reportAnyErrors();
-  return { send:send, recv:recv, swap:swap };
+  return { send:send, recv:recv, swap:swap, ports:elm.ports_out };
 };
 
 function filterListeners(inputs, listeners) {