Support getters and setters (#213)

* evaluate object value members if out is passed

* implement getters and setters for object literals

* update object_macro test

* mention getters and setters in the docs

* update the changelog

compiler/CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Added support for getters and setters.
 - Added brief documentation to some senseable properties.
 - Added typings for the `id` property on symbols.
 - Added the `getBuildings` helper function.

compiler/src/handlers/Object.ts

@@ -1,8 +1,17 @@
 import { CompilerError } from "../CompilerError";
-import { es, IInstruction, IValue, THandler } from "../types";
+import {
+  es,
+  IInstruction,
+  IScope,
+  IValue,
+  TEOutput,
+  THandler,
+  TValueInstructions,
+} from "../types";
 import { extractDestrucuringOut, pipeInsts } from "../utils";
 import {
   AssignmentValue,
+  BaseValue,
   DestructuringValue,
   IObjectValueData,
   LazyValue,
@@ -39,7 +48,19 @@ export const ObjectExpression: THandler = (
     const memberOut = extractDestrucuringOut(out, index);
     const member = pipeInsts(c.handleEval(scope, value, memberOut), inst);
 
-    data[index] = member;
+    if (prop.type !== "ObjectMethod" || prop.kind === "method") {
+      data[index] = member;
+    } else {
+      if (!(data[index] instanceof ObjectGetSetEntry))
+        data[index] = new ObjectGetSetEntry();
+      const entry = data[index] as ObjectGetSetEntry;
+
+      if (prop.kind === "get") {
+        entry.getter = member;
+      } else {
+        entry.setter = member;
+      }
+    }
   }
   return [new ObjectValue(data), inst];
 };
@@ -200,3 +221,27 @@ export const AssignmentPattern: THandler<IValue> = (
 
   return [new AssignmentValue(left, right), inst];
 };
+
+class ObjectGetSetEntry extends BaseValue {
+  macro = true;
+  getter?: IValue;
+  setter?: IValue;
+
+  constructor() {
+    super();
+  }
+
+  eval(scope: IScope, out?: TEOutput): TValueInstructions {
+    if (!this.getter)
+      throw new CompilerError("This property does not have a getter");
+    const [value, inst] = this.getter.call(scope, [], out);
+    return [value ?? new LiteralValue(null), inst];
+  }
+
+  "="(scope: IScope, value: IValue, out?: TEOutput): TValueInstructions {
+    if (!this.setter)
+      throw new CompilerError("This property does not have a setter");
+    const [, inst] = this.setter.call(scope, [value], out);
+    return [value, inst];
+  }
+}

compiler/src/values/ObjectValue.ts

@@ -51,7 +51,9 @@ export class ObjectValue extends VoidValue {
       // constructor or toString
       if (Object.prototype.hasOwnProperty.call(this.data, key.data)) {
         // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-        return [this.data[key.data]!, []];
+        const member = this.data[key.data]!;
+        if (out) return member.eval(scope, out);
+        return [member, []];
       }
     }
 

compiler/test/in/object_macro.js

@@ -5,11 +5,15 @@ const obj = {
   c(number) {
     print("Number is ", number);
   },
+  get d() {
+    return Math.rand(10);
+  },
 };
 
 print(obj.a);
 print(obj.b);
 print(obj[0]);
 obj.c(20);
+print(obj.d);
 
 printFlush();

compiler/test/out/object_macro.mlog

@@ -3,4 +3,6 @@ print "String literal"
 print "number index"
 print "Number is "
 print 20
+op rand &t0:&t1 10
+print &t0:&t1
 printflush message1

website/docs/guide/syntax-support.md

@@ -365,6 +365,7 @@ Behavior:
 
 - Works just like [constants](#variable-declarations), inlines each value on the places it's used.
 - Arrays have a compile time constant `length` property.
+- Objects can be declared with getters and setters
 
 Limitations: