converted namespaces to objects (coming to static objects, singletons)

docs/OOP.md

@@ -40,7 +40,7 @@ Class is the object, naturally, with class:
 
 Classes can be compared:
 
-    println(3.14::class == 2.21::class)
+    println(1.21::class == Math.PI::class)
     println(3.14::class == 1::class)
     println(π::class)
     >>> true

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

@@ -89,14 +89,14 @@ class CompilerContext(val tokens: List<Token>) : ListIterator<Token> by tokens.l
         } else true
     }
 
-    fun ifNextIs(typeId: Token.Type, f: (Token) -> Unit): IfScope {
+    fun ifNextIs(typeId: Token.Type, f: (Token) -> Unit): Boolean {
         val t = next()
         return if (t.type == typeId) {
             f(t)
-            IfScope(true)
+            true
         } else {
             previous()
-            IfScope(false)
+            false
         }
     }
 
@@ -277,22 +277,28 @@ class Compiler {
                 Token.Type.DOT -> {
                     operand?.let { left ->
                         // dotcall: calling method on the operand, if next is ID, "("
-                        cc.ifNextIs(Token.Type.ID) { methodToken ->
+                        var isCall = false
+                        val next = cc.next()
+                        if( next.type == Token.Type.ID) {
                             cc.ifNextIs(Token.Type.LPAREN) {
                                 // instance method call
                                 val args = parseArgs(cc)
+                                isCall = true
                                 operand = Accessor { context ->
-                                    context.pos = methodToken.pos
+                                    context.pos = next.pos
                                     val v = left.getter(context)
                                     v.callInstanceMethod(
                                         context,
-                                        methodToken.value,
+                                        next.value,
                                         args.toArguments()
                                     )
                                 }
                             }
-                        }.otherwise {
+                        }
-                            TODO("implement member access")
+                        if (!isCall) {
+                            operand = Accessor { context ->
+                                left.getter(context).readField(context, next.value)
+                            }
                         }
                     } ?: throw ScriptError(t.pos, "Expecting expression before dot")
                 }
@@ -489,7 +495,10 @@ class Compiler {
                     else -> {
                         Accessor({
                             it.pos = t.pos
-                            it.get(t.value)?.value ?: it.raiseError("symbol not defined: '${t.value}'")
+                            it.get(t.value)?.value?.also {
+                                println("got ${t.value} -> $it")
+                            }
+                                ?: it.raiseError("symbol not defined: '${t.value}'")
                         }) { ctx, newValue ->
                             ctx.get(t.value)?.let { stored ->
                                 ctx.pos = t.pos

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

@@ -37,14 +37,13 @@ class Context(
         objects.put(name, StoredObj(value, isMutable))
     }
 
-    fun getOrCreateNamespace(name: String) =
+    fun getOrCreateNamespace(name: String): ObjNamespace =
         (objects.getOrPut(name) {
             StoredObj(
-                ObjNamespace(name, copy(pos)),
+                ObjNamespace(name),
                 isMutable = false
             )
         }.value as ObjNamespace)
-            .context
 
     inline fun <reified T> addFn(vararg names: String, crossinline fn: suspend Context.() -> T) {
         val newFn = object : Statement() {

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

@@ -26,9 +26,12 @@ sealed class Obj {
     private val monitor = Mutex()
 
     // members: fields most often
-    internal val members = mutableMapOf<String, WithAccess<Obj>>()
+    private val members = mutableMapOf<String, WithAccess<Obj>>()
+
+    //    private val memberMutex = Mutex()
     private val parentInstances = listOf<Obj>()
 
+
     /**
      * Get instance member traversing the hierarchy if needed. Its meaning is different for different objects.
      */
@@ -38,15 +41,18 @@ sealed class Obj {
         return null
     }
 
-    fun getInstanceMember(atPos: Pos, name: String): Obj = getInstanceMemberOrNull(name)
+    fun getInstanceMember(atPos: Pos, name: String): Obj =
+        getInstanceMemberOrNull(name)
             ?: throw ScriptError(atPos, "symbol doesn't exist: $name")
 
-    suspend fun callInstanceMethod(context: Context, name: String,args: Arguments): Obj {
+    suspend fun callInstanceMethod(context: Context, name: String, args: Arguments): Obj =
     // instance _methods_ are our ObjClass instance:
     // note that getInstanceMember traverses the hierarchy
-        return objClass.getInstanceMember(context.pos,name).invoke(context, this, args)
+    // instance _methods_ are our ObjClass instance:
-    }
+    // note that getInstanceMember traverses the hierarchy
-
+// instance _methods_ are our ObjClass instance:
+        // note that getInstanceMember traverses the hierarchy
+        objClass.getInstanceMember(context.pos, name).invoke(context, this, args)
 
     // methods that to override
 
@@ -99,14 +105,22 @@ sealed class Obj {
 
     suspend fun <T> sync(block: () -> T): T = monitor.withLock { block() }
 
-    open suspend fun readField(context: Context, name: String): Obj {
+    suspend fun readField(context: Context, name: String): Obj = getInstanceMember(context.pos, name)
-        context.raiseNotImplemented()
+
+    suspend fun writeField(context: Context, name: String, newValue: Obj) {
+        willMutate(context)
+        members[name]?.let { if (it.isMutable) it.value = newValue }
+            ?: context.raiseError("Can't reassign member: $name")
     }
 
-    open suspend fun writeField(context: Context,name: String, newValue: Obj) {
+    fun createField(name: String, initialValue: Obj, isMutable: Boolean = false, pos: Pos = Pos.builtIn) {
-        context.raiseNotImplemented()
+        if (name in members || parentInstances.any<Obj> { name in it.members })
+            throw ScriptError(pos, "$name is already defined in $objClass or one of its supertypes")
+        members[name] = WithAccess(initialValue, isMutable)
     }
 
+    fun addConst(name: String, value: Obj) = createField(name, value, isMutable = false)
+
     open suspend fun callOn(context: Context): Obj {
         context.raiseNotImplemented()
     }
@@ -202,7 +216,6 @@ fun Obj.toBool(): Boolean =
     (this as? ObjBool)?.value ?: throw IllegalArgumentException("cannot convert to boolean $this")
 
 
-
 data class ObjReal(val value: Double) : Obj(), Numeric {
     override val asStr by lazy { ObjString(value.toString()) }
     override val longValue: Long by lazy { floor(value).toLong() }
@@ -221,11 +234,11 @@ data class ObjReal(val value: Double) : Obj(), Numeric {
 
     companion object {
         val type: ObjClass = ObjClass("Real").apply {
-            members["roundToInt"] = WithAccess(
+            createField(
+                "roundToInt",
                 statement(Pos.builtIn) {
                     (it.thisObj as ObjReal).value.roundToLong().toObj()
                 },
-                false
             )
         }
     }
@@ -275,15 +288,10 @@ data class ObjBool(val value: Boolean) : Obj() {
     override fun toString(): String = value.toString()
 }
 
-data class ObjNamespace(val name: String, val context: Context) : Obj() {
+data class ObjNamespace(val name: String) : Obj() {
     override fun toString(): String {
         return "namespace ${name}"
     }
-
-    override suspend fun readField(callerContext: Context,name: String): Obj {
-        return context[name]?.value ?: callerContext.raiseError("not found: $name")
-    }
-
 }
 
 open class ObjError(val context: Context, val message: String) : Obj() {
@@ -291,3 +299,4 @@ open class ObjError(val context: Context, val message: String) : Obj() {
 }
 
 class ObjNullPointerError(context: Context) : ObjError(context, "object is null")
+

library/src/commonMain/kotlin/net/sergeych/ling/Script.kt

@@ -50,8 +50,8 @@ class Script(
             val z = pi.objClass
             println("PI class $z")
             addConst(pi, "π")
-            getOrCreateNamespace("Math").also { ns ->
+            getOrCreateNamespace("Math").apply {
-                ns.addConst(pi, "PI")
+                addConst( "PI", pi)
             }
         }
     }