diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 69439c2fead..6da3eea9cb1 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -4902,7 +4902,8 @@ JS_DecompileScript(JSContext *cx, JSScript *script, const char *name,
     CHECK_REQUEST(cx);
     jp = JS_NEW_PRINTER(cx, name, NULL,
                         indent & ~JS_DONT_PRETTY_PRINT,
-                        !(indent & JS_DONT_PRETTY_PRINT));
+                        !(indent & JS_DONT_PRETTY_PRINT),
+                        false);
     if (!jp)
         return NULL;
     if (js_DecompileScript(jp, script))
@@ -4916,41 +4917,21 @@ JS_DecompileScript(JSContext *cx, JSScript *script, const char *name,
 JS_PUBLIC_API(JSString *)
 JS_DecompileFunction(JSContext *cx, JSFunction *fun, uintN indent)
 {
-    JSPrinter *jp;
-    JSString *str;
-
     CHECK_REQUEST(cx);
-    jp = JS_NEW_PRINTER(cx, "JS_DecompileFunction", fun,
-                        indent & ~JS_DONT_PRETTY_PRINT,
-                        !(indent & JS_DONT_PRETTY_PRINT));
-    if (!jp)
-        return NULL;
-    if (js_DecompileFunction(jp))
-        str = js_GetPrinterOutput(jp);
-    else
-        str = NULL;
-    js_DestroyPrinter(jp);
-    return str;
+    return js_DecompileToString(cx, "JS_DecompileFunction", fun,
+                                indent & ~JS_DONT_PRETTY_PRINT,
+                                !(indent & JS_DONT_PRETTY_PRINT),
+                                false, js_DecompileFunction);
 }
 
 JS_PUBLIC_API(JSString *)
 JS_DecompileFunctionBody(JSContext *cx, JSFunction *fun, uintN indent)
 {
-    JSPrinter *jp;
-    JSString *str;
-
     CHECK_REQUEST(cx);
-    jp = JS_NEW_PRINTER(cx, "JS_DecompileFunctionBody", fun,
-                        indent & ~JS_DONT_PRETTY_PRINT,
-                        !(indent & JS_DONT_PRETTY_PRINT));
-    if (!jp)
-        return NULL;
-    if (js_DecompileFunctionBody(jp))
-        str = js_GetPrinterOutput(jp);
-    else
-        str = NULL;
-    js_DestroyPrinter(jp);
-    return str;
+    return js_DecompileToString(cx, "JS_DecompileFunctionBody", fun,
+                                indent & ~JS_DONT_PRETTY_PRINT,
+                                !(indent & JS_DONT_PRETTY_PRINT),
+                                false, js_DecompileFunctionBody);
 }
 
 JS_PUBLIC_API(JSBool)
diff --git a/js/src/jsopcode.cpp b/js/src/jsopcode.cpp
index 492f780ef0e..a0b818e7436 100644
--- a/js/src/jsopcode.cpp
+++ b/js/src/jsopcode.cpp
@@ -733,17 +733,9 @@ struct JSPrinter {
     jsuword         *localNames;    /* argument and variable names */
 };
 
-/*
- * Hack another flag, a la JS_DONT_PRETTY_PRINT, into uintN indent parameters
- * to functions such as js_DecompileFunction and js_NewPrinter.  This time, as
- * opposed to JS_DONT_PRETTY_PRINT back in the dark ages, we can assume that a
- * uintN is at least 32 bits.
- */
-#define JS_IN_GROUP_CONTEXT 0x10000
-
 JSPrinter *
 JS_NEW_PRINTER(JSContext *cx, const char *name, JSFunction *fun,
-               uintN indent, JSBool pretty)
+               uintN indent, bool pretty, bool grouped)
 {
     JSPrinter *jp;
 
@@ -752,9 +744,9 @@ JS_NEW_PRINTER(JSContext *cx, const char *name, JSFunction *fun,
         return NULL;
     INIT_SPRINTER(cx, &jp->sprinter, &jp->pool, 0);
     JS_INIT_ARENA_POOL(&jp->pool, name, 256, 1, &cx->scriptStackQuota);
-    jp->indent = indent & ~JS_IN_GROUP_CONTEXT;
+    jp->indent = indent;
     jp->pretty = pretty;
-    jp->grouped = (indent & JS_IN_GROUP_CONTEXT) != 0;
+    jp->grouped = grouped;
     jp->script = NULL;
     jp->dvgfence = NULL;
     jp->pcstack = NULL;
@@ -2252,7 +2244,7 @@ Decompile(SprintStack *ss, jsbytecode *pc, intN nb, JSOp nextop)
                   do_function:
                     js_puts(jp, "\n");
                     jp2 = JS_NEW_PRINTER(cx, "nested_function", fun,
-                                         jp->indent, jp->pretty);
+                                         jp->indent, jp->pretty, jp->grouped);
                     if (!jp2)
                         return NULL;
                     ok = js_DecompileFunction(jp2);
@@ -4145,17 +4137,16 @@ Decompile(SprintStack *ss, jsbytecode *pc, intN nb, JSOp nextop)
 
                 LOAD_FUNCTION(0);
                 {
-                    uintN indent = JS_DONT_PRETTY_PRINT;
-
                     /*
                      * Always parenthesize expression closures. We can't force
                      * saveop to a low-precedence op to arrange for auto-magic
                      * parenthesization without confusing getter/setter code
                      * that checks for JSOP_LAMBDA.
                      */
-                    if (!(fun->flags & JSFUN_EXPR_CLOSURE))
-                        indent |= JS_IN_GROUP_CONTEXT;
-                    str = JS_DecompileFunction(cx, fun, indent);
+                    bool grouped = !(fun->flags & JSFUN_EXPR_CLOSURE);
+                    str = js_DecompileToString(cx, "lambda", fun, 0, 
+                                               false, grouped,
+                                               js_DecompileFunction);
                     if (!str)
                         return NULL;
                 }
@@ -4909,9 +4900,28 @@ js_DecompileScript(JSPrinter *jp, JSScript *script)
     return DecompileCode(jp, script, script->code, (uintN)script->length, 0);
 }
 
+JSString *
+js_DecompileToString(JSContext *cx, const char *name, JSFunction *fun,
+                     uintN indent, bool pretty, bool grouped,
+                     bool (*decompiler)(JSPrinter *jp))
+{
+    JSPrinter *jp;
+    JSString *str;
+
+    jp = JS_NEW_PRINTER(cx, name, fun, indent, pretty, grouped);
+    if (!jp)
+        return NULL;
+    if (decompiler(jp))
+        str = js_GetPrinterOutput(jp);
+    else
+        str = NULL;
+    js_DestroyPrinter(jp);
+    return str;
+}
+
 static const char native_code_str[] = "\t[native code]\n";
 
-JSBool
+bool
 js_DecompileFunctionBody(JSPrinter *jp)
 {
     JSScript *script;
@@ -4927,7 +4937,7 @@ js_DecompileFunctionBody(JSPrinter *jp)
     return DecompileCode(jp, script, script->code, (uintN)script->length, 0);
 }
 
-JSBool
+bool
 js_DecompileFunction(JSPrinter *jp)
 {
     JSFunction *fun;
@@ -5296,7 +5306,8 @@ DecompileExpression(JSContext *cx, JSScript *script, JSFunction *fun,
     }
 
     name = NULL;
-    jp = JS_NEW_PRINTER(cx, "js_DecompileValueGenerator", fun, 0, JS_FALSE);
+    jp = JS_NEW_PRINTER(cx, "js_DecompileValueGenerator", fun, 0,
+                        false, false);
     if (jp) {
         jp->dvgfence = end;
         jp->pcstack = pcstack;
diff --git a/js/src/jsopcode.h b/js/src/jsopcode.h
index a00d066b65f..4bbeb07475d 100644
--- a/js/src/jsopcode.h
+++ b/js/src/jsopcode.h
@@ -276,16 +276,16 @@ js_QuoteString(JSContext *cx, JSString *str, jschar quote);
  */
 
 #ifdef JS_ARENAMETER
-# define JS_NEW_PRINTER(cx, name, fun, indent, pretty)                        \
-    js_NewPrinter(cx, name, fun, indent, pretty)
+# define JS_NEW_PRINTER(cx, name, fun, indent, pretty, grouped)               \
+    js_NewPrinter(cx, name, fun, indent, pretty, grouped)
 #else
-# define JS_NEW_PRINTER(cx, name, fun, indent, pretty)                        \
-    js_NewPrinter(cx, fun, indent, pretty)
+# define JS_NEW_PRINTER(cx, name, fun, indent, pretty, grouped)               \
+    js_NewPrinter(cx, fun, indent, pretty, grouped)
 #endif
 
 extern JSPrinter *
 JS_NEW_PRINTER(JSContext *cx, const char *name, JSFunction *fun,
-               uintN indent, JSBool pretty);
+               uintN indent, bool pretty, bool grouped);
 
 extern void
 js_DestroyPrinter(JSPrinter *jp);
@@ -421,12 +421,17 @@ js_Disassemble1(JSContext *cx, JSScript *script, jsbytecode *pc, uintN loc,
 extern JSBool
 js_DecompileScript(JSPrinter *jp, JSScript *script);
 
-extern JSBool
+extern bool
 js_DecompileFunctionBody(JSPrinter *jp);
 
-extern JSBool
+extern bool
 js_DecompileFunction(JSPrinter *jp);
 
+extern JSString *
+js_DecompileToString(JSContext *cx, const char *name, JSFunction *fun,
+                     uintN indent, bool pretty, bool grouped,
+                     bool (*decompiler)(JSPrinter *jp));
+
 /*
  * Find the source expression that resulted in v, and return a newly allocated
  * C-string containing it.  Fall back on v's string conversion (fallback) if we