core: support multi-level while, break from loops

loop i 5 {
	loop j 6 {
		# This breaks out of both loops
		break 2
	}
}

Signed-off-by: Steve Bennett <steveb@workware.net.au>

2 files changed, 76 insertions, 23 deletions

diff --git a/jim.c b/jim.c
index 11f4efb..d960f54 100644
--- a/jim.c
+++ b/jim.c
@@ -12281,6 +12281,23 @@ static int Jim_UnsetCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *ar
     return JIM_OK;
 }
 
+/**
+ * All commands that support break, continue from a loop (while, loop, foreach, for)
+ * use this to check for returnLevel.
+ *
+ * If returnLevel is > 0, decrements the returnLevel and returns 1.
+ * Otherwise returns 0
+ */
+static int JimCheckLoopRetcode(Jim_Interp *interp, int retval)
+{
+    if (retval == JIM_BREAK || retval == JIM_CONTINUE) {
+        if (--interp->returnLevel > 0) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
 /* [while] */
 static int Jim_WhileCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
@@ -12299,13 +12316,14 @@ static int Jim_WhileCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *ar
             break;
 
         if ((retval = Jim_EvalObj(interp, argv[2])) != JIM_OK) {
+            if (JimCheckLoopRetcode(interp, retval)) {
+                return retval;
+            }
             switch (retval) {
                 case JIM_BREAK:
                     goto out;
-                    break;
                 case JIM_CONTINUE:
                     continue;
-                    break;
                 default:
                     return retval;
             }
@@ -12321,6 +12339,7 @@ static int Jim_ForCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *argv
 {
     int retval;
     int boolean = 1;
+    int immediate = 0;
     Jim_Obj *varNamePtr = NULL;
     Jim_Obj *stopVarNamePtr = NULL;
 
@@ -12441,6 +12460,10 @@ static int Jim_ForCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *argv
 
             /* Eval body */
             retval = Jim_EvalObj(interp, argv[4]);
+            if (JimCheckLoopRetcode(interp, retval)) {
+                immediate++;
+                goto out;
+            }
             if (retval == JIM_OK || retval == JIM_CONTINUE) {
                 retval = JIM_OK;
 
@@ -12477,6 +12500,10 @@ static int Jim_ForCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *argv
             /* increment */
 JIM_IF_OPTIM(evalnext:)
             retval = Jim_EvalObj(interp, argv[3]);
+            if (JimCheckLoopRetcode(interp, retval)) {
+                immediate++;
+                goto out;
+            }
             if (retval == JIM_OK || retval == JIM_CONTINUE) {
                 /* test */
 JIM_IF_OPTIM(testcond:)
@@ -12492,9 +12519,11 @@ JIM_IF_OPTIM(out:)
         Jim_DecrRefCount(interp, varNamePtr);
     }
 
-    if (retval == JIM_CONTINUE || retval == JIM_BREAK || retval == JIM_OK) {
-        Jim_SetEmptyResult(interp);
-        return JIM_OK;
+    if (!immediate) {
+        if (retval == JIM_CONTINUE || retval == JIM_BREAK || retval == JIM_OK) {
+            Jim_SetEmptyResult(interp);
+            return JIM_OK;
+        }
     }
 
     return retval;
@@ -12534,6 +12563,9 @@ static int Jim_LoopCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *arg
 
     while (((i < limit && incr > 0) || (i > limit && incr < 0)) && retval == JIM_OK) {
         retval = Jim_EvalObj(interp, bodyObjPtr);
+        if (JimCheckLoopRetcode(interp, retval)) {
+            return retval;
+        }
         if (retval == JIM_OK || retval == JIM_CONTINUE) {
             Jim_Obj *objPtr = Jim_GetVariable(interp, argv[1], JIM_ERRMSG);
 
@@ -12688,7 +12720,11 @@ static int JimForeachMapHelper(Jim_Interp *interp, int argc, Jim_Obj *const *arg
                 }
             }
         }
-        switch (result = Jim_EvalObj(interp, script)) {
+        result = Jim_EvalObj(interp, script);
+        if (JimCheckLoopRetcode(interp, result)) {
+            goto err;
+        }
+        switch (result) {
             case JIM_OK:
                 if (doMap) {
                     Jim_ListAppendElement(interp, resultObj, interp->result);
@@ -13828,24 +13864,33 @@ static int Jim_ExprCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *arg
     return retcode;
 }
 
-/* [break] */
-static int Jim_BreakCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+static int JimBreakContinueHelper(Jim_Interp *interp, int argc, Jim_Obj *const *argv, int retcode)
 {
-    if (argc != 1) {
-        Jim_WrongNumArgs(interp, 1, argv, "");
+    if (argc != 1 && argc != 2) {
+        Jim_WrongNumArgs(interp, 1, argv, "?level?");
         return JIM_ERR;
     }
-    return JIM_BREAK;
+    if (argc == 2) {
+        long level;
+        int ret = Jim_GetLong(interp, argv[1], &level);
+        if (ret != JIM_OK) {
+            return ret;
+        }
+        interp->returnLevel = level;
+    }
+    return retcode;
+}
+
+/* [break] */
+static int Jim_BreakCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+    return JimBreakContinueHelper(interp, argc, argv, JIM_BREAK);
 }
 
 /* [continue] */
 static int Jim_ContinueCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
-    if (argc != 1) {
-        Jim_WrongNumArgs(interp, 1, argv, "");
-        return JIM_ERR;
-    }
-    return JIM_CONTINUE;
+    return JimBreakContinueHelper(interp, argc, argv, JIM_CONTINUE);
 }
 
 /* [return] */
diff --git a/tests/jim.test b/tests/jim.test
index b2a9337..e6de376 100644
--- a/tests/jim.test
+++ b/tests/jim.test
@@ -2002,9 +2002,13 @@ test foreach-7.3 {continue tests} {
 } {b}
 test foreach-7.4 {continue tests} {catch {continue foo} msg} 1
 test foreach-7.5 {continue tests} {
+	catch {continue foo blah} msg
+  set msg
+} {wrong # args: should be "continue ?level?"}
+test foreach-7.6 {continue tests} {
 	catch {continue foo} msg
   set msg
-} {wrong # args: should be "continue"}
+} {expected integer but got "foo"}
 
 # Check "break".
 
@@ -2019,9 +2023,13 @@ test foreach-8.2 {break tests} {
 } {a b}
 test foreach-8.3 {break tests} {catch {break foo} msg} 1
 test foreach-8.4 {break tests} {
-  catch {break foo} msg
+  catch {break foo blah} msg
+  set msg
+} {wrong # args: should be "break ?level?"}
+test foreach-8.6 {break tests} {
+	catch {break foo} msg
   set msg
-} {wrong # args: should be "break"}
+} {expected integer but got "foo"}
 
 # Test for incorrect "double evaluation" semantics
 
@@ -2792,9 +2800,9 @@ test for-1.15 {TclCompileForCmd: for command result} {
 # Check "for" and "continue".
 
 test for-2.1 {TclCompileContinueCmd: arguments after "continue"} {
-    catch {continue foo} msg
+    catch {continue foo blah} msg
     set msg
-} {wrong # args: should be "continue"}
+} {wrong # args: should be "continue ?level?"}
 test for-2.2 {TclCompileContinueCmd: continue result} {
     catch continue
 } 4
@@ -2863,9 +2871,9 @@ test for-2.6 {continue tests, long command body} {
 # Check "for" and "break".
 
 test for-3.1 {TclCompileBreakCmd: arguments after "break"} {
-    catch {break foo} msg
+    catch {break foo blah} msg
     set msg
-} {wrong # args: should be "break"}
+} {wrong # args: should be "break ?level?"}
 test for-3.2 {TclCompileBreakCmd: break result} {
     catch break
 } 3