optimizing refactoring: no more StoredObj.kt, WithAccess now always deals with Obj and is renamed to ObjRecord

library/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt

@@ -132,7 +132,7 @@ class Compiler(
                                 operand = Accessor { context ->
                                     context.pos = next.pos
                                     val v = left.getter(context).value
-                                    WithAccess(
+                                    ObjRecord(
                                         v.invokeInstanceMethod(
                                             context,
                                             next.value,
@@ -641,7 +641,7 @@ class Compiler(
                     else -> {
                         Accessor({
                             it.pos = t.pos
-                            it.get(t.value)?.asAccess
+                            it.get(t.value)
                                 ?: it.raiseError("symbol not defined: '${t.value}'")
                         }) { ctx, newValue ->
                             ctx.get(t.value)?.let { stored ->
@@ -886,7 +886,7 @@ class Compiler(
     }
 
     private suspend fun loopIntRange(
-        forContext: Context, start: Int, end: Int, loopVar: StoredObj,
+        forContext: Context, start: Int, end: Int, loopVar: ObjRecord,
         body: Statement, elseStatement: Statement?, label: String?, catchBreak: Boolean
     ): Obj {
         var result: Obj = ObjVoid
@@ -914,7 +914,7 @@ class Compiler(
     }
 
     private suspend fun loopIterable(
-        forContext: Context, sourceObj: Obj, loopVar: StoredObj,
+        forContext: Context, sourceObj: Obj, loopVar: ObjRecord,
         body: Statement, elseStatement: Statement?, label: String?,
         catchBreak: Boolean
     ): Obj {

library/src/commonMain/kotlin/net/sergeych/lyng/Context.kt

@@ -56,9 +56,9 @@ class Context(
     inline fun <reified T : Obj> thisAs(): T = (thisObj as? T)
         ?: raiseClassCastError("Cannot cast ${thisObj.objClass.className} to ${T::class.simpleName}")
 
-    private val objects = mutableMapOf<String, StoredObj>()
+    private val objects = mutableMapOf<String, ObjRecord>()
 
-    operator fun get(name: String): StoredObj? =
+    operator fun get(name: String): ObjRecord? =
         objects[name]
             ?: parent?.get(name)
 
@@ -70,12 +70,12 @@ class Context(
 
     fun copy() = Context(this, args, pos, thisObj)
 
-    fun addItem(name: String, isMutable: Boolean, value: Obj?): StoredObj {
+    fun addItem(name: String, isMutable: Boolean, value: Obj): ObjRecord {
-        return StoredObj(value, isMutable).also { objects.put(name, it) }
+        return ObjRecord(value, isMutable).also { objects.put(name, it) }
     }
 
     fun getOrCreateNamespace(name: String): ObjClass {
-        val ns = objects.getOrPut(name) { StoredObj(ObjNamespace(name), isMutable = false) }.value
+        val ns = objects.getOrPut(name) { ObjRecord(ObjNamespace(name), isMutable = false) }.value
         return ns!!.objClass
     }
 

library/src/commonMain/kotlin/net/sergeych/lyng/Obj.kt

@@ -6,20 +6,35 @@ import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import net.sergeych.synctools.ProtectedOp
 
-//typealias InstanceMethod = (Context, Obj) -> Obj
+/**
-
+ * Record to store object with access rules, e.g. [isMutable] and access level [visibility].
-data class WithAccess<T>(
+ */
-    var value: T,
+data class ObjRecord(
+    var value: Obj,
     val isMutable: Boolean,
     val visibility: Compiler.Visibility = Compiler.Visibility.Public
 )
 
+/**
+ * When we need read-write access to an object in some abstract storage, we need Accessor,
+ * as in-site assigning is not always sufficient, in general case we need to replace the object
+ * in the storage.
+ *
+ * Note that assigning new value is more complex than just replacing the object, see how assignment
+ * operator is implemented in [Compiler.allOps].
+ */
 data class Accessor(
-    val getter: suspend (Context) -> WithAccess<Obj>,
+    val getter: suspend (Context) -> ObjRecord,
     val setterOrNull: (suspend (Context, Obj) -> Unit)?
 ) {
-    constructor(getter: suspend (Context) -> WithAccess<Obj>) : this(getter, null)
+    /**
+     * Simplified constructor for immutable stores.
+     */
+    constructor(getter: suspend (Context) -> ObjRecord) : this(getter, null)
 
+    /**
+     * Get the setter or throw.
+     */
     fun setter(pos: Pos) = setterOrNull ?: throw ScriptError(pos, "can't assign value")
 }
 
@@ -164,13 +179,13 @@ open class Obj {
 
     suspend fun <T> sync(block: () -> T): T = monitor.withLock { block() }
 
-    suspend fun readField(context: Context, name: String): WithAccess<Obj> {
+    suspend fun readField(context: Context, name: String): ObjRecord {
         // could be property or class field:
         val obj = objClass.getInstanceMemberOrNull(name)
         val value = obj?.value
         return when (value) {
             is Statement -> {
-                WithAccess(value.execute(context.copy(context.pos, newThisObj = this)), obj.isMutable)
+                ObjRecord(value.execute(context.copy(context.pos, newThisObj = this)), obj.isMutable)
             }
             // could be writable property naturally
             null -> ObjNull.asReadonly
@@ -221,8 +236,8 @@ open class Obj {
         callOn(context.copy(atPos, args = args, newThisObj = thisObj))
 
 
-    val asReadonly: WithAccess<Obj> by lazy { WithAccess(this, false) }
+    val asReadonly: ObjRecord by lazy { ObjRecord(this, false) }
-    val asMutable: WithAccess<Obj> by lazy { WithAccess(this, true) }
+    val asMutable: ObjRecord by lazy { ObjRecord(this, true) }
 
 
     companion object {

library/src/commonMain/kotlin/net/sergeych/lyng/ObjClass.kt

@@ -16,7 +16,7 @@ class ObjClass(
     override val objClass: ObjClass by lazy { ObjClassType }
 
     // members: fields most often
-    private val members = mutableMapOf<String, WithAccess<Obj>>()
+    private val members = mutableMapOf<String, ObjRecord>()
 
     override fun toString(): String = className
 
@@ -46,7 +46,7 @@ class ObjClass(
     ) {
         if (name in members || allParentsSet.any { name in it.members } == true)
             throw ScriptError(pos, "$name is already defined in $objClass or one of its supertypes")
-        members[name] = WithAccess(initialValue, isMutable)
+        members[name] = ObjRecord(initialValue, isMutable)
     }
 
     fun addFn(name: String, isOpen: Boolean = false, code: suspend Context.() -> Obj) {
@@ -59,13 +59,13 @@ class ObjClass(
     /**
      * Get instance member traversing the hierarchy if needed. Its meaning is different for different objects.
      */
-    fun getInstanceMemberOrNull(name: String): WithAccess<Obj>? {
+    fun getInstanceMemberOrNull(name: String): ObjRecord? {
         members[name]?.let { return it }
         allParentsSet.forEach { parent -> parent.getInstanceMemberOrNull(name)?.let { return it } }
         return null
     }
 
-    fun getInstanceMember(atPos: Pos, name: String): WithAccess<Obj> =
+    fun getInstanceMember(atPos: Pos, name: String): ObjRecord =
         getInstanceMemberOrNull(name)
             ?: throw ScriptError(atPos, "symbol doesn't exist: $name")
 }

library/src/commonMain/kotlin/net/sergeych/lyng/StoredObj.kt

@@ -1,11 +0,0 @@
-package net.sergeych.lyng
-
-/**
- * Whatever [Obj] stored somewhere
- */
-data class StoredObj(
-    var value: Obj?,
-    val isMutable: Boolean = false
-) {
-    val asAccess: WithAccess<Obj>? get() = value?.let { WithAccess(it, isMutable) }
-}