experiment: viewport width and viewport height are accessible.

js-assembler/runtime-src/runtime.js

@@ -112,7 +112,7 @@ if(this['plt'] === undefined) { this['plt'] = {}; }
 		    var elt = MACHINE.env.pop();
 		    var outputPort = 
 			MACHINE.params.currentOutputPort;
-		    if (elt !== undefined) {
+		    if (elt !== VOID) {
 			outputPort.writeDomNode(MACHINE, toDomNode(elt, 'print'));
 			outputPort.writeDomNode(MACHINE, toDomNode("\n", 'print'));
 		    }
@@ -520,94 +520,113 @@ if(this['plt'] === undefined) { this['plt'] = {}; }
     // are coded here; several of them (including call/cc) are injected by
     // the bootstrapping code.
     var Primitives = {};
-    Primitives['display'] = function(MACHINE) {
+
-	var firstArg = MACHINE.env[MACHINE.env.length-1];
+    var installPrimitiveProcedure = function(name, arity, f) {
-	var outputPort = MACHINE.params.currentOutputPort;
+        Primitives[name] = f;
-	if (MACHINE.argcount === 2) {
+        Primitives[name].arity = arity;
-	    testArgument(MACHINE,
+        Primitives[name].displayName = name;
-			 'isOutputPort', 
-			 isOutputPort, 
-			 MACHINE.env.length-2,
-			 1,
-			 'display');
-	    outputPort = MACHINE.env[MACHINE.env.length-2];
-	}
-	outputPort.writeDomNode(MACHINE, toDomNode(firstArg, 'display'));
-        return VOID;
     };
-    Primitives['display'].arity = makeList(1, 2);
-    Primitives['display'].displayName = 'display';
 
-
+    var installPrimitiveConstant = function(name, v) {
-    Primitives['newline'] = function(MACHINE) {
+        Primitives[name] = v;
-	var outputPort = MACHINE.params.currentOutputPort;
-	if (MACHINE.argcount === 1) { 
-	    testArgument(MACHINE,
-			 'isOutputPort', 
-			 isOutputPort, 
-			 MACHINE.env.length-1,
-			 1,
-			 'newline');
-	    outputPort = MACHINE.env[MACHINE.env.length-1];
-	}
-	outputPort.writeDomNode(MACHINE, toDomNode("\n", 'display'));
-        return VOID;
     };
-    Primitives['newline'].arity = makeList(0, 1);
-    Primitives['newline'].displayName = 'newline';
 
 
-    Primitives['displayln'] = function(MACHINE){
+    installPrimitiveConstant('pi', jsnums.pi);
-	var firstArg = MACHINE.env[MACHINE.env.length-1];
+    installPrimitiveConstant('e', jsnums.e);
-	var outputPort = MACHINE.params.currentOutputPort;
-	if (MACHINE.argcount === 2) {
-	    testArgument(MACHINE,
-			 'isOutputPort', 
-			 isOutputPort, 
-			 MACHINE.env.length-2,
-			 1,
-			 'displayln'); 
-	    outputPort = MACHINE.env[MACHINE.env.length-2];
-	}
-	outputPort.writeDomNode(MACHINE, toDomNode(firstArg, 'display'));
-	outputPort.writeDomNode(MACHINE, toDomNode("\n", 'display'));
-        return VOID;
-    };
-    Primitives['displayln'].arity = makeList(1, 2);
-    Primitives['displayln'].displayName = 'displayln';
 
-
+    installPrimitiveProcedure(
-
+        'display', makeList(1, 2),
-    Primitives['current-print'] = function(MACHINE) {
+        function(MACHINE) {
-	return MACHINE.params['current-print'];
+	    var firstArg = MACHINE.env[MACHINE.env.length-1];
-    };
+	    var outputPort = MACHINE.params.currentOutputPort;
-    Primitives['current-print'].arity = makeList(0, 1);
+	    if (MACHINE.argcount === 2) {
-    Primitives['current-print'].displayName = "current-print";
+	        testArgument(MACHINE,
-
+			     'isOutputPort', 
-    Primitives['pi'] = jsnums.pi;
+			     isOutputPort, 
-
+			     MACHINE.env.length-2,
-    Primitives['e'] = jsnums.e;
+			     1,
-
+			     'display');
-    Primitives['='] = function(MACHINE) {
+	        outputPort = MACHINE.env[MACHINE.env.length-2];
-	var firstArg = MACHINE.env[MACHINE.env.length-1];
-	testArgument(MACHINE, 'number', isNumber, firstArg, 0, '=');
-	for (var i = 0; i < MACHINE.argcount - 1; i++) {
-	    testArgument(MACHINE, 
-			 'number',
-			 isNumber, 
-			 MACHINE.env[MACHINE.env.length - 1 - i],
-			 i,
-			 '=');
-	    if (! (jsnums.equals(MACHINE.env[MACHINE.env.length - 1 - i],
-		                 MACHINE.env[MACHINE.env.length - 1 - i - 1]))) {
-		return false; 
 	    }
-	}
+	    outputPort.writeDomNode(MACHINE, toDomNode(firstArg, 'display'));
-	return true;
+            return VOID;
-    };
+        });
-    Primitives['='].arity = new ArityAtLeast(2);
-    Primitives['='].displayName = '=';
 
+    installPrimitiveProcedure(
+        'newline', makeList(0, 1),
+        function(MACHINE) {
+	    var outputPort = MACHINE.params.currentOutputPort;
+	    if (MACHINE.argcount === 1) { 
+	        testArgument(MACHINE,
+			     'isOutputPort', 
+			     isOutputPort, 
+			     MACHINE.env.length-1,
+			     1,
+			     'newline');
+	        outputPort = MACHINE.env[MACHINE.env.length-1];
+	    }
+	    outputPort.writeDomNode(MACHINE, toDomNode("\n", 'display'));
+            return VOID;
+        });
+
+    installPrimitiveProcedure(
+        'displayln',
+        makeList(1, 2),
+        function(MACHINE){
+	    var firstArg = MACHINE.env[MACHINE.env.length-1];
+	    var outputPort = MACHINE.params.currentOutputPort;
+	    if (MACHINE.argcount === 2) {
+	        testArgument(MACHINE,
+			     'isOutputPort', 
+			     isOutputPort, 
+			     MACHINE.env.length-2,
+			     1,
+			     'displayln'); 
+	        outputPort = MACHINE.env[MACHINE.env.length-2];
+	    }
+	    outputPort.writeDomNode(MACHINE, toDomNode(firstArg, 'display'));
+	    outputPort.writeDomNode(MACHINE, toDomNode("\n", 'display'));
+            return VOID;
+        });
+
+
+    installPrimitiveProcedure(
+        'current-print',
+        makeList(0, 1),
+        function(MACHINE) {
+            if (MACHINE.argcount === 1) {
+                MACHINE.params['current-print'] = MACHINE.env[MACHINE.env.length - 1];
+                return VOID;
+            } else {
+	        return MACHINE.params['current-print'];
+            }
+        });
+
+
+    installPrimitiveProcedure(
+        '=',
+        new ArityAtLeast(2),
+        function(MACHINE) {
+	    var firstArg = MACHINE.env[MACHINE.env.length-1];
+	    testArgument(MACHINE, 'number', isNumber, firstArg, 0, '=');
+	    for (var i = 0; i < MACHINE.argcount - 1; i++) {
+	        testArgument(MACHINE, 
+			     'number',
+			     isNumber, 
+			     MACHINE.env[MACHINE.env.length - 1 - i],
+			     i,
+			     '=');
+	        if (! (jsnums.equals(MACHINE.env[MACHINE.env.length - 1 - i],
+		                     MACHINE.env[MACHINE.env.length - 1 - i - 1]))) {
+		    return false; 
+	        }
+	    }
+	    return true;
+        });
+
+
+    // TODO: use installPrimitiveProcedure for the rest...
 
     Primitives['<'] = function(MACHINE) {
 	var firstArg = MACHINE.env[MACHINE.env.length-1];
@@ -1161,6 +1180,24 @@ if(this['plt'] === undefined) { this['plt'] = {}; }
 
 
 
+    // Extensions.  A small experiment.
+    installPrimitiveProcedure(
+        'viewport-width',
+        0,
+        function(MACHINE) {
+            return $(window).width();
+        });
+
+    installPrimitiveProcedure(
+        'viewport-height',
+        0,
+        function(MACHINE) {
+            return $(window).height();
+        });
+
+
+
+
 
 
     // recomputeGas: state number -> number
@@ -1342,6 +1379,9 @@ if(this['plt'] === undefined) { this['plt'] = {}; }
     exports['currentMachine'] = new Machine();
     exports['invokeMains'] = invokeMains;
 
+
+    // installing new primitives
+    exports['installPrimitiveProcedure'] = installPrimitiveProcedure;
     exports['Primitives'] = Primitives;
     
     exports['ready'] = ready;
@@ -1417,5 +1457,7 @@ if(this['plt'] === undefined) { this['plt'] = {}; }
     exports['HaltError'] = HaltError;
 
 
+
+
     scope.link.announceReady('runtime');
 })(this['plt']);

lang/kernel.rkt

@@ -148,7 +148,7 @@
  display
  newline
 
- #;displayln
+;;  displayln
 
 ;;  current-print
 ;;  current-continuation-marks
@@ -394,6 +394,27 @@
 ;;  make-reader-graph
 ;;  make-placeholder
 ;;  placeholder-set!
-
-
  )
+
+
+
+
+
+(provide
+ ;; FIXME:
+ ;; Extensions: these may need to be hidden in a JavaScript-implemented module
+ viewport-width
+ viewport-height)
+
+
+
+;; viewport-width: -> natural
+;; The viewport width in pixels.
+(define (viewport-width)
+  (error 'viewport-width "Not available outside JavaScript context."))
+
+
+;; viewport-height: -> natural
+;; The viewport height in pixels.
+(define (viewport-height)
+  (error 'viewport-width "Not available outside JavaScript context."))