No longer wrapping complex types in an auxiliary JSON object

pom.xml

@@ -250,7 +250,7 @@
                         <include>**/org/rascalmpl/test/library/LibraryLangPaths.java</include>
                         <include>**/org/rascalmpl/test/value/AllTests.java</include>
                         <include>**/org/rascalmpl/test/repl/*Test.java</include>
-                        <include>**/org/rascalmpl/test/rpc/*Test.java</include>
+                        <include>**/org/rascalmpl/test/rpc/*Tests.java</include>
                         <include>**/org/rascalmpl/util/**/*Test.java</include>
                         <include>**/org/rascalmpl/util/**/*Tests.java</include>
                         <include>**/org/rascalmpl/uri/**/*Test.java</include>

src/org/rascalmpl/ideservices/GsonUtils.java

@@ -27,15 +27,16 @@
 package org.rascalmpl.ideservices;
 
 import java.io.IOException;
-import java.io.StringWriter;
+import java.io.StringReader;
 import java.util.List;
+import java.util.function.Consumer;
 
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.rascalmpl.interpreter.NullRascalMonitor;
 import org.rascalmpl.library.lang.json.internal.JsonValueReader;
 import org.rascalmpl.library.lang.json.internal.JsonValueWriter;
 import org.rascalmpl.util.base64.StreamingBase64;
-import org.rascalmpl.values.IRascalValueFactory;
+import org.rascalmpl.values.ValueFactoryFactory;
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
@@ -59,6 +60,8 @@
 import io.usethesource.vallang.IString;
 import io.usethesource.vallang.ITuple;
 import io.usethesource.vallang.IValue;
+import io.usethesource.vallang.IValueFactory;
+import io.usethesource.vallang.io.StandardTextReader;
 import io.usethesource.vallang.io.binary.stream.IValueInputStream;
 import io.usethesource.vallang.io.binary.stream.IValueOutputStream;
 import io.usethesource.vallang.type.Type;
@@ -71,16 +74,16 @@
  */
 public class GsonUtils {
     private static final JsonValueWriter writer = new JsonValueWriter();
-    private static final JsonValueReader reader = new JsonValueReader(IRascalValueFactory.getInstance(), new TypeStore(), new NullRascalMonitor(), null);
     private static final TypeFactory tf = TypeFactory.getInstance();
+    private static final IValueFactory vf = ValueFactoryFactory.getValueFactory();
 
     private static final List<TypeMapping> typeMappings;
 
     /* Mappings from Java types to `vallang` types are declared here.
      * Subtypes should be declared before their supertypes; e.g., `Number` and `Value` appear last.
      */
     static {
-        writer.setDatesAsInt(true);
+        writer.setRationalsAsString(true);
         typeMappings = List.of(
             new TypeMapping(IBool.class, tf.boolType()),
             new TypeMapping(ICollection.class), // IList, IMap, ISet
@@ -100,9 +103,26 @@ public class GsonUtils {
     }
 
     public static enum ComplexTypeMode {
+        /**
+         * Complex values are serialized as JSON objects. Automatic deserialization is only supported for primitive types (`bool`,
+         * `datetime`, `int`, `rat`, `real`, `loc`, `str`, `num`); more complex types cannot be automatically deserialized as
+         * the type is not available at deserialization time.
+         */
         ENCODE_AS_JSON_OBJECT,
+
+        /**
+         * Complex values are serialized as a Base64-encoded string. A properly filled {@link TypeStore} is required for deserialization.
+         */
         ENCODE_AS_BASE64_STRING,
+
+        /**
+         * Complex values are serialized as a string. A properly filled {@link TypeStore} is required for deserialization.
+         */
         ENCODE_AS_STRING,
+
+        /**
+         * Only values of primitive type are supported; more complex values are neither serialized nor deserialized.
+         */
         NOT_SUPPORTED
     }
 
@@ -129,35 +149,19 @@ public boolean supports(Class<?> incoming) {
             return clazz.isAssignableFrom(incoming);
         }
 
-        public <T> TypeAdapter<T> createAdapter(ComplexTypeMode complexTypeMode) {
+        public <T> TypeAdapter<T> createAdapter(ComplexTypeMode complexTypeMode, TypeStore ts) {
+            var reader = new JsonValueReader(vf, ts, new NullRascalMonitor(), null);
             if (isPrimitive) {
                 return new TypeAdapter<T>() {
                     @Override
                     public void write(JsonWriter out, T value) throws IOException {
-                        var needsWrapping = needsWrapping(type, complexTypeMode);
-                        if (needsWrapping) {
-                            out.beginObject();
-                            out.name("val");
-                        }
                         writer.write(out, (IValue) value);
-                        if (needsWrapping) {
-                            out.endObject();
-                        }
                     }
 
                     @SuppressWarnings("unchecked")
                     @Override
                     public T read(JsonReader in) throws IOException {
-                        var needsWrapping = needsWrapping(type, complexTypeMode);
-                        if (needsWrapping) {
-                            in.beginObject();
-                            in.nextName();
-                        }
-                        var ret = (T) reader.read(in, type);
-                        if (needsWrapping) {
-                            in.endObject();
-                        }
-                        return ret;
+                        return (T) reader.read(in, type);
                     }
                 };
             }
@@ -166,15 +170,7 @@ public T read(JsonReader in) throws IOException {
                 public void write(JsonWriter out, T value) throws IOException {
                     switch (complexTypeMode) {
                         case ENCODE_AS_JSON_OBJECT:
-                            var needsWrapping = needsWrapping(type, complexTypeMode);
-                            if (needsWrapping) {
-                                out.beginObject();
-                                out.name("val");
-                            }
                             writer.write(out, (IValue) value);
-                            if (needsWrapping) {
-                                out.endObject();
-                            }
                             break;
                         case ENCODE_AS_BASE64_STRING:
                             out.value(base64Encode((IValue) value));
@@ -189,29 +185,81 @@ public void write(JsonWriter out, T value) throws IOException {
                     }
                 }
 
+                @SuppressWarnings("unchecked")
                 @Override
                 public T read(JsonReader in) throws IOException {
-                    throw new IOException("Cannot handle complex type");
+                    switch (complexTypeMode) {
+                        case ENCODE_AS_BASE64_STRING:
+                            return base64Decode(in.nextString(), ts);
+                        case ENCODE_AS_STRING:
+                            return (T) new StandardTextReader().read(vf, ts, tf.valueType(), new StringReader(in.nextString()));
+                        default:
+                            throw new IOException("Cannot handle complex type");
+                    }
                 }
             };
         }
     }
-
+
+    /**
+     * Configure Gson to encode complex (non-primitive) values as JSON objects.
+     * 
+     * See {@link ComplexTypeMode.ENCODE_AS_JSON_OBJECT}.
+     */
+    public static Consumer<GsonBuilder> complexAsJsonObject() {
+        return builder -> configureGson(builder, ComplexTypeMode.ENCODE_AS_JSON_OBJECT, new TypeStore());
+    }
+
     /**
-     * IValues that are encoded as a (JSON) list need to be wrapped in an object to avoid Gson accidentally unpacking the list
-     * @param type
-     * @param complexTypeMode
-     * @return whether or not wrapping is required 
+     * Configure Gson to encode complex (non-primitive) values as Base64-encoded strings.
+     * 
+     * This configurtion should only be used for serialization; deserialization requires a {@link TypeStore).
      */
-    private static boolean needsWrapping(Type type, ComplexTypeMode complexTypeMode) {
-        return complexTypeMode == ComplexTypeMode.ENCODE_AS_JSON_OBJECT && type == null || type.isSubtypeOf(tf.rationalType());
+    public static Consumer<GsonBuilder> complexAsBase64String() {
+        return builder -> complexAsBase64String(new TypeStore());
     }
 
-    public static void configureGson(GsonBuilder builder) {
-        configureGson(builder, ComplexTypeMode.ENCODE_AS_JSON_OBJECT);
+    /**
+     * Configure Gson to encode complex (non-primitive) values as Base64-encoded strings.
+     * 
+     * This configuration can be used for both serialization and deserialization.
+     * 
+     * @param ts The {@link TypeStore} to be used during deserialization.
+     */
+    public static Consumer<GsonBuilder> complexAsBase64String(TypeStore ts) {
+        return builder -> configureGson(builder, ComplexTypeMode.ENCODE_AS_BASE64_STRING, ts);
+    }
+
+    /**
+     * Configure Gson to encode complex (non-primitive) values as plain strings.
+     * 
+     * This configurtion should only be used for serialization; deserialization requires a {@link TypeStore).
+     */
+    public static Consumer<GsonBuilder> complexAsString() {
+        return builder -> complexAsString(new TypeStore());
+    }
+
+    /**
+     * Configure Gson to encode complex (non-primitive) values as plain strings.
+     * 
+     * This configuration can be used for both serialization and deserialization.
+     * 
+     * @param ts The {@link TypeStore} to be used during deserialization.
+     */
+    public static Consumer<GsonBuilder> complexAsString(TypeStore ts) {
+        return builder -> configureGson(builder, ComplexTypeMode.ENCODE_AS_STRING, ts);
+    }
+
+    /**
+     * Configure Gson to encode encode primitive values only. Complex values raise an exception.
+     * 
+     * @param builder The {@link GsonBuilder} to be configured.
+     */
+    public static Consumer<GsonBuilder> noComplexTypes() {
+        return builder -> configureGson(builder, ComplexTypeMode.NOT_SUPPORTED, new TypeStore());
     }
 
-    public static void configureGson(GsonBuilder builder, ComplexTypeMode complexTypeMode) {
+    public static void configureGson(GsonBuilder builder, ComplexTypeMode complexTypeMode, TypeStore ts) {
         builder.registerTypeAdapterFactory(new TypeAdapterFactory() {
             @Override
             public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
@@ -222,7 +270,7 @@ public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
                 return typeMappings.stream()
                     .filter(m -> m.supports(rawType))
                     .findFirst()
-                    .map(m -> m.<T>createAdapter(complexTypeMode))
+                    .map(m -> m.<T>createAdapter(complexTypeMode, ts))
                     .orElse(null);
             }
         });
@@ -231,7 +279,7 @@ public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
     public static String base64Encode(IValue value) {
         var builder = new StringBuilder();
         try (var encoder = StreamingBase64.encode(builder);
-             var out = new IValueOutputStream(encoder, IRascalValueFactory.getInstance())) {
+             var out = new IValueOutputStream(encoder, vf)) {
             out.write(value);
         } catch (IOException e) {
             throw new RuntimeException(e);
@@ -242,7 +290,7 @@ public static String base64Encode(IValue value) {
     @SuppressWarnings("unchecked")
     public static <T extends IValue> T base64Decode(String string, TypeStore ts) {
         try (var decoder = StreamingBase64.decode(string);
-             var in = new IValueInputStream(decoder, IRascalValueFactory.getInstance(), () -> ts)) {
+             var in = new IValueInputStream(decoder, vf, () -> ts)) {
             return (T) in.read();
         } catch (IOException e) {
             throw new RuntimeException(e);

src/org/rascalmpl/ideservices/RemoteIDEServices.java

@@ -64,7 +64,7 @@ public RemoteIDEServices(int ideServicesPort, PrintWriter stderr, IRascalMonitor
                 .setLocalService(this)
                 .setInput(socket.getInputStream())
                 .setOutput(socket.getOutputStream())
-                .configureGson(GsonUtils::configureGson)
+                .configureGson(GsonUtils.complexAsJsonObject())
                 .setExecutorService(DaemonThreadPool.buildConstrainedCached("rascal-ide-services", Math.max(2, Math.min(6, Runtime.getRuntime().availableProcessors() - 2))))
                 .create();
 

src/org/rascalmpl/library/Content.rsc

@@ -81,7 +81,8 @@ which involves a handy, automatic, encoding of Rascal values into json values.
 data Response 
   = response(Status status, str mimeType, map[str,str] header, str content)
   | fileResponse(loc file, str mimeType, map[str,str] header)
-  | jsonResponse(Status status, map[str,str] header, value val, str dateTimeFormat = "yyyy-MM-dd\'T\'HH:mm:ss\'Z\'", JSONFormatter[value] formatter = str (value _) { fail; }, bool explicitConstructorNames=false, bool explicitDataTypes=false)
+  | jsonResponse(Status status, map[str,str] header, value val, str dateTimeFormat = "yyyy-MM-dd\'T\'HH:mm:ss\'Z\'", JSONFormatter[value] formatter = str (value _) { fail; },
+      bool explicitConstructorNames=false, bool explicitDataTypes=false, bool dateTimeAsInt=true, bool rationalsAsString=false)
   ;
 
 @synopsis{Utility to quickly render a string as HTML content}  

src/org/rascalmpl/library/lang/json/IO.java

@@ -111,7 +111,7 @@ public IValue parseJSON(IValue type, IString src, IString dateTimeFormat, IBool
     }
 
     public void writeJSON(ISourceLocation loc, IValue value, IBool unpackedLocations, IString dateTimeFormat,
-        IBool dateTimeAsInt, IInteger indent, IBool dropOrigins, IFunction formatter, IBool explicitConstructorNames,
+        IBool dateTimeAsInt, IBool rationalsAsString, IInteger indent, IBool dropOrigins, IFunction formatter, IBool explicitConstructorNames,
         IBool explicitDataTypes) {
         try (JsonWriter out =
             new JsonWriter(new OutputStreamWriter(URIResolverRegistry.getInstance().getOutputStream(loc, false),
@@ -123,6 +123,7 @@ public void writeJSON(ISourceLocation loc, IValue value, IBool unpackedLocations
             new JsonValueWriter()
                 .setCalendarFormat(dateTimeFormat.getValue())
                 .setDatesAsInt(dateTimeAsInt.getValue())
+                .setRationalsAsString(rationalsAsString.getValue())
                 .setUnpackedLocations(unpackedLocations.getValue())
                 .setDropOrigins(dropOrigins.getValue())
                 .setFormatters(formatter)
@@ -135,7 +136,7 @@ public void writeJSON(ISourceLocation loc, IValue value, IBool unpackedLocations
         }
     }
 
-    public IString asJSON(IValue value, IBool unpackedLocations, IString dateTimeFormat, IBool dateTimeAsInt,
+    public IString asJSON(IValue value, IBool unpackedLocations, IString dateTimeFormat, IBool dateTimeAsInt, IBool rationalsAsString,
         IInteger indent, IBool dropOrigins, IFunction formatter, IBool explicitConstructorNames,
         IBool explicitDataTypes) {
         StringWriter string = new StringWriter();
@@ -147,6 +148,7 @@ public IString asJSON(IValue value, IBool unpackedLocations, IString dateTimeFor
             new JsonValueWriter()
                 .setCalendarFormat(dateTimeFormat.getValue())
                 .setDatesAsInt(dateTimeAsInt.getValue())
+                .setRationalsAsString(rationalsAsString.getValue())
                 .setUnpackedLocations(unpackedLocations.getValue())
                 .setDropOrigins(dropOrigins.getValue())
                 .setFormatters(formatter)

src/org/rascalmpl/library/lang/json/IO.rsc

@@ -162,7 +162,8 @@ For `real` numbers that are larger than JVM's double you get "negative infinity"
 java void writeJSON(loc target, value val, 
   bool unpackedLocations=false, 
   str dateTimeFormat=DEFAULT_DATETIME_FORMAT, 
-  bool dateTimeAsInt=false, 
+  bool dateTimeAsInt=false,
+  bool rationalsAsString=false,
   int indent=0, 
   bool dropOrigins=true, 
   JSONFormatter[value] formatter = str (value _) { fail; }, 
@@ -176,7 +177,7 @@ java void writeJSON(loc target, value val,
 @description{
 This function uses `writeJSON` and stores the result in a string.
 }
-java str asJSON(value val, bool unpackedLocations=false, str dateTimeFormat=DEFAULT_DATETIME_FORMAT, bool dateTimeAsInt=false, int indent = 0, bool dropOrigins=true, JSONFormatter[value] formatter = str (value _) { fail; }, bool explicitConstructorNames=false, bool explicitDataTypes=false);
+java str asJSON(value val, bool unpackedLocations=false, str dateTimeFormat=DEFAULT_DATETIME_FORMAT, bool dateTimeAsInt=false, bool rationalsAsString=false, int indent = 0, bool dropOrigins=true, JSONFormatter[value] formatter = str (value _) { fail; }, bool explicitConstructorNames=false, bool explicitDataTypes=false);
 
 @synopsis{((writeJSON)) and ((asJSON)) uses `Formatter` functions to flatten structured data to strings, on-demand}
 @description{

src/org/rascalmpl/library/lang/json/internal/JsonValueReader.java

@@ -376,7 +376,7 @@ public IValue visitRational(Type type) throws IOException {
                 case STRING:
                     return vf.rational(nextString());
                 default:
-                    throw parseErrorHere("Expected integer but got " + in.peek());
+                    throw parseErrorHere("Expected rational but got " + in.peek());
             }
         }
 

src/org/rascalmpl/library/lang/json/internal/JsonValueWriter.java

@@ -61,6 +61,7 @@
 public class JsonValueWriter {
     private ThreadLocal<SimpleDateFormat> format;
     private boolean datesAsInts = true;
+    private boolean rationalsAsString = false;
     private boolean unpackedLocations = false;
     private boolean dropOrigins = true;
     private IFunction formatters;
@@ -127,6 +128,11 @@ public JsonValueWriter setDatesAsInt(boolean setting) {
         return this;
     }
 
+    public JsonValueWriter setRationalsAsString(boolean setting) {
+        this.rationalsAsString = setting;
+        return this;
+    }
+
     public JsonValueWriter setUnpackedLocations(boolean setting) {
         this.unpackedLocations = setting;
         return this;
@@ -175,10 +181,14 @@ public Void visitReal(IReal o) throws IOException {
 
             @Override
             public Void visitRational(IRational o) throws IOException {
-                out.beginArray();
-                o.numerator().accept(this);
-                o.denominator().accept(this);
-                out.endArray();
+                if (rationalsAsString) {
+                    out.value(o.toString());
+                } else {
+                    out.beginArray();
+                    o.numerator().accept(this);
+                    o.denominator().accept(this);
+                    out.endArray();
+                }
 
                 return null;
             }