v1.0.5-SNAPSHOT started json and kotlinx serialization support

docs/json_and_kotlin_serialization.md

@@ -0,0 +1,43 @@
+# Json support
+
+Since 1.0.5 we start adding JSON support. 
+
+Right now we only support basic types: maps, lists, strings, numbers, booleans. It is not yet capable of serializing classes. This functionality will be added in the 1.0.6 release.
+
+## Serializae to kotlin string
+
+    // in lyng
+    assertEquals("{\"a\":1}", {a: 1}.toJsonString())
+    void
+    >>> void
+
+From the kotln side, you can use `Obj.toJson()` and deserialization helpers:
+
+```kotlin
+/**
+ * Decodes the current object into a deserialized form using the provided deserialization strategy.
+ * It is based on [Obj.toJson] and uses existing Kotlin Json serialization, without string representation
+ * (only `JsonElement` to carry information between Kotlin and Lyng serialization worlds), thus efficient.
+ *
+ * @param strategy The deserialization strategy that defines how the object should be decoded.
+ * @param scope An optional scope used during deserialization to define the context. Defaults to a new instance of Scope.
+ * @return The deserialized object of type T.
+ */
+suspend fun <T>Obj.decodeSerializableWith(strategy: DeserializationStrategy<T>, scope: Scope = Scope()): T =
+    Json.decodeFromJsonElement(strategy,toJson(scope))
+
+/**
+ * Decodes a serializable object of type [T] using the provided decoding scope. The deserialization uses
+ * [Obj.toJson] and existing Json based serialization ithout using actual string representation, thus
+ * efficient.
+ *
+ * @param T The type of the object to be decoded. Must be a reified type.
+ * @param scope The scope used during decoding. Defaults to a new instance of [Scope].
+ */
+suspend inline fun <reified T>Obj.decodeSerializable(scope: Scope= Scope()) =
+    decodeSerializableWith<T>(serializer<T>(), scope)
+```
+
+Note that lyng-2-kotlin deserialization with `kotlinx.serialization` is working based on JsonElement as information carrier, without formatting and parsing actual Json strings. This is why we use `Json.decodeFromJsonElement` instead of `Json.decodeFromString`. Such approach gives satisfactory performance without writing and supporting custom `kotlinx.serialization` codecs.
+
+

docs/tutorial.md

@@ -205,7 +205,7 @@ Much like let, but it does not alter returned value:
     >>> void
 
 While it is not altering return value, the source object could be changed:
-
+also
     class Point(x,y)
     val p = Point(1,2).also { it.x++ }
     assertEquals(p.x, 2)
@@ -1533,7 +1533,7 @@ assertEquals(null, (buzz as? Foo)?.runA())
 
 Notes:
 - Resolution order uses C3 MRO (active): deterministic, monotonic order suitable for diamonds and complex hierarchies. Example: for `class D() : B(), C()` where both `B()` and `C()` derive from `A()`, the C3 order is `D → B → C → A`. The first visible match wins.
-- `private` is visible only inside the declaring class; `protected` is visible from the declaring class and any of its transitive subclasses. Qualification (`this@Type`) or casts do not bypass visibility.
+- `private` is visible only inside the declaring class; `protected` is visible from the declaring class and any of its transitive subclasses. Qualialsofication (`this@Type`) or casts do not bypass visibility.
 - Safe‑call `?.` works with `as?` for optional dispatch.
 
 To get details on OOP in Lyng, see [OOP notes](oop.md).

lynglib/build.gradle.kts

@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 group = "net.sergeych"
-version = "1.0.4-SNAPSHOT"
+version = "1.0.5-SNAPSHOT"
 
 // Removed legacy buildscript classpath declarations; plugins are applied via the plugins DSL below
 

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/Obj.kt

@@ -17,8 +17,13 @@
 
 package net.sergeych.lyng.obj
 
+import kotlinx.serialization.DeserializationStrategy
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonNull
+import kotlinx.serialization.serializer
 import net.sergeych.lyng.*
 import net.sergeych.lynon.LynonDecoder
 import net.sergeych.lynon.LynonEncoder
@@ -376,6 +381,10 @@ open class Obj {
         return null
     }
 
+    open suspend fun toJson(scope: Scope = Scope()): JsonElement {
+        scope.raiseNotImplemented("toJson for ${objClass.className}")
+    }
+
     companion object {
 
         val rootObjectType = ObjClass("Obj").apply {
@@ -418,7 +427,9 @@ open class Obj {
                 thisObj.putAt(this, requiredArg<Obj>(0), newValue)
                 newValue
             }
-
+            addFn("toJsonString") {
+                thisObj.toJson(this).toString().toObj()
+            }
         }
 
 
@@ -520,6 +531,10 @@ object ObjNull : Obj() {
         }
     }
 
+    override suspend fun toJson(scope: Scope): JsonElement {
+        return JsonNull
+    }
+
     override val objClass: ObjClass by lazy {
         object : ObjClass("Null") {
             override suspend fun deserialize(scope: Scope, decoder: LynonDecoder, lynonType: LynonType?): Obj {
@@ -572,4 +587,25 @@ data class ObjNamespace(val name: String) : Obj() {
     }
 }
 
+/**
+ * Decodes the current object into a deserialized form using the provided deserialization strategy.
+ * It is based on [Obj.toJson] and uses existing Kotlin Json serialization, without string representation
+ * (only `JsonElement` to carry information between Kotlin and Lyng serialization worlds), thus efficient.
+ *
+ * @param strategy The deserialization strategy that defines how the object should be decoded.
+ * @param scope An optional scope used during deserialization to define the context. Defaults to a new instance of Scope.
+ * @return The deserialized object of type T.
+ */
+suspend fun <T>Obj.decodeSerializableWith(strategy: DeserializationStrategy<T>, scope: Scope = Scope()): T =
+    Json.decodeFromJsonElement(strategy,toJson(scope))
 
+/**
+ * Decodes a serializable object of type [T] using the provided decoding scope. The deserialization uses
+ * [Obj.toJson] and existing Json based serialization ithout using actual string representation, thus
+ * efficient.
+ *
+ * @param T The type of the object to be decoded. Must be a reified type.
+ * @param scope The scope used during decoding. Defaults to a new instance of [Scope].
+ */
+suspend inline fun <reified T>Obj.decodeSerializable(scope: Scope= Scope()) =
+    decodeSerializableWith<T>(serializer<T>(), scope)

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjBool.kt

@@ -17,6 +17,8 @@
 
 package net.sergeych.lyng.obj
 
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonPrimitive
 import net.sergeych.lyng.Scope
 import net.sergeych.lynon.LynonDecoder
 import net.sergeych.lynon.LynonEncoder
@@ -62,6 +64,10 @@ data class ObjBool(val value: Boolean) : Obj() {
         return value == other.value
     }
 
+    override suspend fun toJson(scope: Scope): JsonElement {
+        return JsonPrimitive(value)
+    }
+
     companion object {
         val type = object : ObjClass("Bool") {
             override suspend fun deserialize(scope: Scope, decoder: LynonDecoder,lynonType: LynonType?): Obj {

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjInt.kt

@@ -17,6 +17,8 @@
 
 package net.sergeych.lyng.obj
 
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonPrimitive
 import net.sergeych.lyng.Scope
 import net.sergeych.lynon.LynonDecoder
 import net.sergeych.lynon.LynonEncoder
@@ -161,6 +163,10 @@ class ObjInt(var value: Long, override val isConst: Boolean = false) : Obj(), Nu
         }
     }
 
+    override suspend fun toJson(scope: Scope): JsonElement {
+        return JsonPrimitive(value)
+    }
+
     companion object {
         val Zero = ObjInt(0, true)
         val One = ObjInt(1, true)

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjList.kt

@@ -17,6 +17,8 @@
 
 package net.sergeych.lyng.obj
 
+import kotlinx.serialization.json.JsonArray
+import kotlinx.serialization.json.JsonElement
 import net.sergeych.lyng.Scope
 import net.sergeych.lyng.Statement
 import net.sergeych.lyng.statement
@@ -188,6 +190,10 @@ class ObjList(val list: MutableList<Obj> = mutableListOf()) : Obj() {
 
     override suspend fun lynonType(): LynonType = LynonType.List
 
+    override suspend fun toJson(scope: Scope): JsonElement {
+        return JsonArray(list.map { it.toJson(scope) })
+    }
+
     companion object {
         val type = object : ObjClass("List", ObjArray) {
             override suspend fun deserialize(scope: Scope, decoder: LynonDecoder, lynonType: LynonType?): Obj {

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjMap.kt

@@ -17,6 +17,8 @@
 
 package net.sergeych.lyng.obj
 
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonObject
 import net.sergeych.lyng.Scope
 import net.sergeych.lyng.Statement
 import net.sergeych.lynon.LynonDecoder
@@ -141,6 +143,12 @@ class ObjMap(val map: MutableMap<Obj, Obj> = mutableMapOf()) : Obj() {
         encoder.encodeAnyList(scope, values, fixedSize = true)
     }
 
+    override suspend fun toJson(scope: Scope): JsonElement {
+        return JsonObject(
+            map.map { it.key.toString(scope).value to it.value.toJson(scope) }.toMap()
+        )
+    }
+
     companion object {
 
         suspend fun listToMap(scope: Scope, list: List<Obj>): MutableMap<Obj, Obj> {

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjReal.kt

@@ -17,6 +17,8 @@
 
 package net.sergeych.lyng.obj
 
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonPrimitive
 import net.sergeych.lyng.Pos
 import net.sergeych.lyng.Scope
 import net.sergeych.lyng.statement
@@ -100,6 +102,10 @@ data class ObjReal(val value: Double) : Obj(), Numeric {
         encoder.encodeReal(value)
     }
 
+    override suspend fun toJson(scope: Scope): JsonElement {
+        return JsonPrimitive(value)
+    }
+
     companion object {
         val type: ObjClass = object : ObjClass("Real") {
             override suspend fun deserialize(scope: Scope, decoder: LynonDecoder, lynonType: LynonType?): Obj =

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjString.kt

@@ -19,6 +19,8 @@ package net.sergeych.lyng.obj
 
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonPrimitive
 import net.sergeych.lyng.PerfFlags
 import net.sergeych.lyng.RegexCache
 import net.sergeych.lyng.Scope
@@ -116,6 +118,10 @@ data class ObjString(val value: String) : Obj() {
         encoder.encodeBinaryData(value.encodeToByteArray())
     }
 
+    override suspend fun toJson(scope: Scope): JsonElement {
+        return JsonPrimitive(value)
+    }
+
     companion object {
         val type = object : ObjClass("String") {
             override suspend fun deserialize(scope: Scope, decoder: LynonDecoder, lynonType: LynonType?): Obj =

lynglib/src/commonTest/kotlin/ScriptTest.kt

@@ -23,6 +23,7 @@ import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.test.runTest
 import kotlinx.coroutines.withContext
 import kotlinx.coroutines.withTimeout
+import kotlinx.serialization.Serializable
 import net.sergeych.lyng.*
 import net.sergeych.lyng.obj.*
 import net.sergeych.lyng.pacman.InlineSourcesImportProvider
@@ -3797,8 +3798,21 @@ class ScriptTest {
            
         """
         )
+    }
 
+    @Serializable
+    data class JSTest1(val foo: String,val one: Int, val ok: Boolean)
 
+    @Test
+    fun testToJson() = runTest {
+        val x = eval("""{ "foo": "bar", "one": 1, "ok": true }""")
+        println(x.toJson())
+        assertEquals(x.toJson().toString(), """{"foo":"bar","one":1,"ok":true}""")
+        assertEquals(
+            (eval("""{ "foo": "bar", "one": 1, "ok": true }.toJsonString()""") as ObjString).value,
+            """{"foo":"bar","one":1,"ok":true}""")
+        println(x.decodeSerializable<JSTest1>())
+        assertEquals(JSTest1("bar", 1, true), x.decodeSerializable<JSTest1>())
     }
 
 }

lynglib/src/jvmTest/kotlin/BookTest.kt

@@ -352,4 +352,9 @@ class BookTest {
     fun testRegex() = runBlocking {
         runDocTests("../docs/Regex.md")
     }
+
+    @Test
+    fun testJson() = runBlocking {
+        runDocTests("../docs/json_and_kotlin_serialization.md")
+    }
 }