diff --git a/whalesong/js-assembler/runtime-src/baselib-functions.js b/whalesong/js-assembler/runtime-src/baselib-functions.js
index 5c613ef..bfe3a08 100644
--- a/whalesong/js-assembler/runtime-src/baselib-functions.js
+++ b/whalesong/js-assembler/runtime-src/baselib-functions.js
@@ -203,12 +203,12 @@
         var i;
 
         if (MACHINE.breakScheduled) {
-            MACHINE.breakScheduled = false;
-            return fail(baselib.exceptions.makeExnBreak("User break.",
-                                                        MACHINE.captureContinuationMarks(),
-                                                        // FIXME: capture the continuation as well,
-                                                        // rather than just hold false.
-                                                        false));
+            return fail(baselib.exceptions.makeExnBreak(
+                "User break.",
+                MACHINE.captureContinuationMarks(),
+                // FIXME: capture the continuation as well,
+                // rather than just hold false.
+                false));
         }
 
         var oldArgcount, oldVal, oldProc, oldErrorHandler, oldControlLength, oldEnvLength;
diff --git a/whalesong/js-assembler/runtime-src/runtime.js b/whalesong/js-assembler/runtime-src/runtime.js
index 4364008..33bd573 100644
--- a/whalesong/js-assembler/runtime-src/runtime.js
+++ b/whalesong/js-assembler/runtime-src/runtime.js
@@ -329,12 +329,16 @@
         this.globals = {};
 	this.primitives = Primitives;
         this.exclusiveLock = new ExclusiveLock();
-        this.breakScheduled = false;
+        this.breakScheduled = false;      // (U boolean function)
     };
 
     // Schedule a break the next time the trampoline begins.
-    Machine.prototype.scheduleBreak = function() {
-        this.breakScheduled = true;
+    Machine.prototype.scheduleBreak = function(afterBreak) {
+        if (typeof afterBreak === 'function') {
+            this.breakScheduled = afterBreak;
+        } else {
+            this.breakScheduled = true;
+        }
     };
 
 
@@ -486,8 +490,12 @@
 
     // Checks to see if we need to handle break.  If so, returns true.
     // Otherwise, returns false.
-    var maybeHandleBreak = function(MACHINE) {
-        if (MACHINE.breakScheduled) {
+    //
+    // FIXME: This logic is duplicated within one of the catch blocks
+    // in the trampoline.  Would be nice to refactor.
+    var maybeHandleBreakOutsideTrampoline = function(MACHINE) {
+        var breakScheduled = MACHINE.breakScheduled;
+        if (breakScheduled) {
             MACHINE.breakScheduled = false;
             MACHINE.running = false;
             MACHINE.params.currentErrorHandler(
@@ -499,6 +507,9 @@
                                  // FIXME: capture the continuation as well,
                                  // rather than just hold false.
                                  false)));
+            if (typeof breakScheduled === 'function') {
+                setTimeout(breakScheduled, 0);
+            }
             return true;
         }
         return false;
@@ -507,7 +518,10 @@
     var scheduleTrampoline = function(MACHINE, f, release) {
         setTimeout(
 	    function() {
-                if (maybeHandleBreak(MACHINE)) { release(); return; }
+                if (maybeHandleBreakOutsideTrampoline(MACHINE)) {
+                    release(); 
+                    return; 
+                }
                 MACHINE._trampoline(f, false, release);
             },
             0);
@@ -659,13 +673,26 @@
                     return;
                 } else if (e instanceof HaltError) {
                     that.running = false;
+                    that.breakScheduled = false;
                     e.onHalt(that);
                     release();
                     return;
+                } else if (e instanceof baselib.exceptions.RacketError &&
+                           baselib.exceptions.isExnBreak(e.racketError)) {
+                    var oldBreakScheduled = that.breakScheduled;
+                    if (typeof oldBreakScheduled === 'function') {
+                        setTimeout(oldBreakScheduled, 0);
+                    }
+                    that.running = false;
+                    that.breakScheduled = false;
+                    that.params.currentErrorHandler(that, e);
+                    release();
+                    return;
                 } else {
                     // General error condition: just exit out
                     // of the trampoline and call the current error handler.
                     that.running = false;
+                    that.breakScheduled = false;
                     that.params.currentErrorHandler(that, e);
                     release();
                     return;
@@ -673,6 +700,7 @@
             }
         }
         that.running = false;
+        that.breakScheduled = false;
         that.params.currentSuccessHandler(that);
         release();
         return;
diff --git a/whalesong/repl-prototype/htdocs/repl.js b/whalesong/repl-prototype/htdocs/repl.js
index 7debf47..5b7afab 100644
--- a/whalesong/repl-prototype/htdocs/repl.js
+++ b/whalesong/repl-prototype/htdocs/repl.js
@@ -1,14 +1,13 @@
 jQuery(document).ready(function() {
     "use strict";    
-    if (! console.log) { console.log = function() { }; }
+
+    // if (! console.log) { console.log = function() { }; }
 
     var repl = jQuery("#repl");
     var output = jQuery("#output");
     var breakButton = jQuery("#break");
     var resetButton = jQuery("#reset");
-    breakButton.hide();
-    breakButton.click(function() { interruptEvaluation(); });
-    resetButton.click(function() { output.empty(); setupMachine(); });
+
 
 
     // The machine.
@@ -23,6 +22,30 @@ jQuery(document).ready(function() {
         { remote: 'rpc.html' },
         { remote: { replCompile: {} } });
 
+
+    var onBreak = function() {
+        if (M.running) { 
+            interruptEvaluation(function(){}); 
+        } 
+    };
+
+    var onReset = function() {
+        if (M.running) {
+            M.params.currentDisplayer = 
+                function(MACHINE, domNode) {};
+            M.params.currentErrorDisplayer =
+                function(MACHINE, domNode) {};
+            interruptEvaluation(
+                function() {
+                    output.empty(); 
+                    setupMachine();
+                });
+        } else {
+            output.empty(); 
+            setupMachine();
+        }
+    };
+
     
     var setupMachine = function() { 
         M = plt.runtime.currentMachine;
@@ -98,11 +121,11 @@ jQuery(document).ready(function() {
     // writeErrorMessage: string -> void
     // Write out an error message.
     var writeErrorMessage = function(msg) {
-        jQuery("<span/>")
-            .text(''+msg)
-            .css("color", "red")
-            .appendTo(output);
-        jQuery("<br/>").appendTo(output);
+        M.params.currentErrorDisplayer(M,
+                                  jQuery("<span/>")
+                                  .text(''+msg)
+                                  .css("color", "red"));
+        M.params.currentErrorDisplayer(M, jQuery("<br/>"));
         sendOutputToBottom();
     };
 
@@ -121,16 +144,19 @@ jQuery(document).ready(function() {
 	}
     };
 
-    var interruptEvaluation = function() {
-        M.scheduleBreak();
+    var interruptEvaluation = function(afterBreak) {
+        if (! M.running) {
+            throw new Error("internal error: trying to interrupt evaluation but nothing is running.");
+        }
+        M.scheduleBreak(afterBreak);
     };
 
 
     // In evaluation, we'll send compilation requests to the server,
     // and get back bytecode that we should evaluate.
     var compileAndEvaluate = function(src, after) {
-        jQuery("<tt/>").text('> ' + src).appendTo(output);
-        jQuery("<br/>").appendTo(output);
+        M.params.currentDisplayer(M, jQuery("<tt/>").text('> ' + src));
+        M.params.currentDisplayer(M, jQuery("<br/>"));
         var onCompile = function(compiledResult) {
             if (compiledResult.type === 'repl') {
                 return onGoodReplCompile(compiledResult);
@@ -177,7 +203,6 @@ jQuery(document).ready(function() {
                      after);
         };
         var onServerError = function(err) {
-            console.log(err);
             writeErrorMessage("internal server error");
             after();
         };
@@ -199,5 +224,9 @@ jQuery(document).ready(function() {
     // Test: compile a module.
     //
 
+
+    breakButton.hide();
+    breakButton.click(onBreak);
+    resetButton.click(onReset);
     setupMachine();
 });