add interactive debugging to default condition handler

language/src/main/java/com/github/arvyy/islisp/ISLISPTruffleLanguageView.java

@@ -28,6 +28,6 @@ public ISLISPTruffleLanguageView(ISLISPContext context, Object object) {
 
     @ExportMessage
     Object toDisplayString(boolean ignored) {
-        return ISLISPFormatObject.format(object);
+        return ISLISPFormatObject.format(object, false);
     }
 }

language/src/main/java/com/github/arvyy/islisp/exceptions/ISLISPNonContinuableCondition.java → language/src/main/java/com/github/arvyy/islisp/exceptions/ISLISPUncaughtConditionException.java

@@ -3,14 +3,10 @@
 import com.oracle.truffle.api.exception.AbstractTruffleException;
 
 /**
- * Control flow exception that unwinds stack from point of signal
- * to the handler for non-continuable conditions.
- *
- * See
- * @{@link com.github.arvyy.islisp.functions.ISLISPSignalCondition},
- * @{@link com.github.arvyy.islisp.nodes.ISLISPWithHandlerNode}.
+ * Exception thrown in case a condition is signalled, but no
+ * signal handler is present (can happen if an islisp function is stored and reinvoked from non-islisp context).
  */
-public class ISLISPNonContinuableCondition extends AbstractTruffleException {
+public class ISLISPUncaughtConditionException extends AbstractTruffleException {
 
     private final Object condition;
 
@@ -19,7 +15,7 @@ public class ISLISPNonContinuableCondition extends AbstractTruffleException {
      *
      * @param condition condition value
      */
-    public ISLISPNonContinuableCondition(Object condition) {
+    public ISLISPUncaughtConditionException(Object condition) {
         this.condition = condition;
     }
 
@@ -29,4 +25,5 @@ public ISLISPNonContinuableCondition(Object condition) {
     public Object getCondition() {
         return condition;
     }
+
 }

language/src/main/java/com/github/arvyy/islisp/functions/ISLISPDefaultHandler.java

@@ -1,9 +1,10 @@
 package com.github.arvyy.islisp.functions;
 
 import com.github.arvyy.islisp.ISLISPContext;
-import com.github.arvyy.islisp.exceptions.ISLISPInteractiveExitException;
+import com.github.arvyy.islisp.exceptions.ISLISPError;
 import com.github.arvyy.islisp.nodes.ISLISPFunctionDispatchNode;
 import com.github.arvyy.islisp.nodes.ISLISPFunctionDispatchNodeGen;
+import com.github.arvyy.islisp.nodes.ISLISPInteractiveDebugger;
 import com.github.arvyy.islisp.runtime.LispFunction;
 import com.oracle.truffle.api.TruffleLanguage;
 import com.oracle.truffle.api.frame.VirtualFrame;
@@ -20,12 +21,19 @@ public class ISLISPDefaultHandler extends RootNode {
     @Child
     private ISLISPFunctionDispatchNode dispatchNode;
 
+    @Child
+    private ISLISPInteractiveDebugger interactiveDebugger;
+
     private final boolean isInteractive;
 
-    ISLISPDefaultHandler(TruffleLanguage<?> language, boolean isInteractive) {
+    ISLISPDefaultHandler(
+        TruffleLanguage<?> language,
+        boolean isInteractive
+    ) {
         super(language);
         this.isInteractive = isInteractive;
         dispatchNode = ISLISPFunctionDispatchNodeGen.create();
+        interactiveDebugger = new ISLISPInteractiveDebugger();
     }
 
     @Override
@@ -41,7 +49,8 @@ public Object execute(VirtualFrame frame) {
         var condition = frame.getArguments()[1];
         dispatchNode.executeDispatch(reportConditionFunction, new Object[]{condition, errorOutput});
         if (isInteractive) {
-            throw new ISLISPInteractiveExitException(condition);
+            interactiveDebugger.startRepl(condition);
+            throw new ISLISPError("Interactive debugger returned normally", this);
         } else {
             return dispatchNode.executeDispatch(exitFunction, new Object[] {1});
         }

language/src/main/java/com/github/arvyy/islisp/functions/ISLISPFormatObject.java

@@ -55,13 +55,14 @@ Object doFallback(Object stream, Object obj, Object escape) {
      * Util java procedure to give same string representation as what format-object produces.
      *
      * @param o value
+     * @param escape if values should be present in a readable form (eg., show double quotes for string)
      * @return display string
      */
     @CompilerDirectives.TruffleBoundary
-    public static String format(Object o) {
+    public static String format(Object o, boolean escape) {
         try {
             var stream = new LispStream(null, new ByteArrayOutputStream());
-            doPrint(stream, o, false);
+            doPrint(stream, o, escape);
             return stream.getOutputString().get();
         } catch (Exception e) {
             return "";

language/src/main/java/com/github/arvyy/islisp/functions/ISLISPSignalCondition.java

@@ -1,9 +1,10 @@
 package com.github.arvyy.islisp.functions;
 
 import com.github.arvyy.islisp.ISLISPContext;
+import com.github.arvyy.islisp.Utils;
 import com.github.arvyy.islisp.exceptions.ISLISPContinueException;
 import com.github.arvyy.islisp.exceptions.ISLISPError;
-import com.github.arvyy.islisp.exceptions.ISLISPNonContinuableCondition;
+import com.github.arvyy.islisp.exceptions.ISLISPUncaughtConditionException;
 import com.github.arvyy.islisp.nodes.ISLISPErrorSignalerNode;
 import com.github.arvyy.islisp.nodes.ISLISPFunctionDispatchNode;
 import com.github.arvyy.islisp.nodes.ISLISPFunctionDispatchNodeGen;
@@ -80,28 +81,29 @@ public Object execute(VirtualFrame frame) {
         }
         var continuable = frame.getArguments()[2];
         setContinuable.call(null, continuable, conditionValue);
-        if (continuable != ctx.getNil()) {
-            var handler = ctx.popHandler();
-            // it's possible no handler is active, in which case treat it same as non-continuable.
-            // (eg., in a case when islisp function was returned from eval, and then called
-            // from a different truffle language / context)
-            if (handler == null) {
-                throw new ISLISPNonContinuableCondition(conditionValue);
-            }
-            try {
-                dispatchNode.executeDispatch(handler, new Object[]{conditionValue});
-                throw new ISLISPError("Condition handler returned normally", this);
-            } catch (ISLISPContinueException e) {
-                if (e.getCondition() == conditionValue) {
-                    return e.getValue();
-                } else {
-                    throw e;
+        var handler = ctx.popHandler();
+        // it's possible no handler is active, in which case throw special exception to indicate it.
+        // (eg., in a case when islisp function was returned from eval, and then called
+        // from a different truffle language / context)
+        if (handler == null) {
+            throw new ISLISPUncaughtConditionException(conditionValue);
+        }
+        try {
+            dispatchNode.executeDispatch(handler, new Object[]{conditionValue});
+            // ISLISP spec requires handler to do non-local transfer
+            throw new ISLISPError("Condition handler returned normally", this);
+        } catch (ISLISPContinueException e) {
+            if (e.getCondition() == conditionValue) {
+                // non-continuable exception shouldn't be able to be continued >:(
+                if (Utils.isNil(continuable)) {
+                    throw new ISLISPError("Condition is not continuable", this);
                 }
-            } finally {
-                ctx.pushHandler(handler);
+                return e.getValue();
+            } else {
+                throw e;
             }
-        } else {
-            throw new ISLISPNonContinuableCondition(conditionValue);
+        } finally {
+            ctx.pushHandler(handler);
         }
     }
 

language/src/main/java/com/github/arvyy/islisp/nodes/ISLISPErrorSignalerNode.java

@@ -153,7 +153,7 @@ public Object signalWrongArgumentCount(int actual, int min, int max) {
             sRequiredMin(), min,
             sRequiredMax(), max
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -209,7 +209,7 @@ public Object signalDomainError(String message, Object obj, LispClass expectedCl
             sObject(), obj,
             sExpectedClass(), expectedClass
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -226,7 +226,7 @@ public Object signalUnboundVariable(Symbol name) {
             ctx.namedSymbol("name"), name,
             ctx.namedSymbol("namespace"), ctx.namedSymbol("variable")
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -243,7 +243,7 @@ public Object signalUndefinedFunction(Symbol name) {
             ctx.namedSymbol("name"), name,
             ctx.namedSymbol("namespace"), ctx.namedSymbol("function")
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -260,7 +260,7 @@ public Object signalUndefinedClass(Symbol name) {
             ctx.namedSymbol("name"), name,
             ctx.namedSymbol("namespace"), ctx.namedSymbol("class")
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     @CompilerDirectives.TruffleBoundary
@@ -305,7 +305,7 @@ public Object signalEndOfStream() {
             null,
             ctx.lookupClass("ROOT", ctx.namedSymbol("<end-of-stream>"))
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -319,7 +319,7 @@ public Object signalDivisionByZero() {
             null,
             ctx.lookupClass("ROOT", ctx.namedSymbol("<division-by-zero>"))
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -337,7 +337,7 @@ public Object signalIndexOutOfRange(int actual, int bounds) {
             sBounds(), bounds,
             sActual(), actual
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -351,7 +351,7 @@ public Object signalNoNextMethod() {
             null,
             ctx.lookupClass("ROOT", ctx.namedSymbol("<no-next-method-error>"))
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -368,7 +368,7 @@ public Object signalTruffleInteropError(InteropException interopException) {
             cTruffleInteropError(),
             sMessage(), interopException.getMessage()
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
 
@@ -386,7 +386,7 @@ public Object signalIOError(IOException exception) {
             ctx.lookupClass("ROOT", ctx.namedSymbol("<io-error>")),
             ctx.namedSymbol("message"), exception.getMessage()
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -404,7 +404,7 @@ public Object signalUnknownConversion(Object value, Object to) {
             ctx.namedSymbol("value"), value,
             ctx.namedSymbol("to"), to
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 
     /**
@@ -420,6 +420,6 @@ public Object signalImmutableBindingError(Symbol bindingName) {
             ctx.lookupClass("ROOT", ctx.namedSymbol("<immutable-binding-error>")),
             ctx.namedSymbol("binding"), bindingName
         );
-        return getSignalCallNode().call(null, condition, ctx.getNil());
+        return getSignalCallNode().call(null, condition, ctx.getT());
     }
 }