Implement object literal parsing; Instantiate classes from object literals

Essentially, if the contextual type is a class with a constructor that takes zero arguments or doesn't have a constructor at all, an object literal can be used to initialize a new instance of that class with preset values.

Author: dcodeIO

.gitattributes

@@ -1,3 +1,3 @@
 bin/* text eol=lf
-dist/* -diff
+dist/* binary
 scripts/*.sh eol=lf

dist/assemblyscript.js

@@ -432,6 +432,18 @@ export abstract class Node {
     return expr;
   }
 
+  static createObjectLiteralExpression(
+    names: IdentifierExpression[],
+    values: Expression[],
+    range: Range
+  ): ObjectLiteralExpression {
+    var expr = new ObjectLiteralExpression();
+    expr.range = range;
+    expr.names = names;
+    expr.values = values;
+    return expr;
+  }
+
   static createParenthesizedExpression(
     expression: Expression,
     range: Range
@@ -1363,6 +1375,16 @@ export class NullExpression extends IdentifierExpression {
   text = "null";
 }
 
+/** Represents an object literal expression. */
+export class ObjectLiteralExpression extends LiteralExpression {
+  literalKind = LiteralKind.OBJECT;
+
+  /** Field names. */
+  names: IdentifierExpression[];
+  /** Field values. */
+  values: Expression[];
+}
+
 /** Represents a parenthesized expression. */
 export class ParenthesizedExpression extends Expression {
   kind = NodeKind.PARENTHESIZED;

dist/assemblyscript.js.map

@@ -71,7 +71,11 @@ export enum CommonFlags {
   /** Is a virtual method. */
   VIRTUAL = 1 << 26,
   /** Is the main function. */
-  MAIN = 1 << 27
+  MAIN = 1 << 27,
+
+  // Other
+
+  QUOTED = 1 << 28
 }
 
 /** Path delimiter inserted between file system levels. */

src/ast.ts

@@ -130,6 +130,7 @@ import {
   LiteralExpression,
   LiteralKind,
   NewExpression,
+  ObjectLiteralExpression,
   ParenthesizedExpression,
   PropertyAccessExpression,
   TernaryExpression,
@@ -6144,7 +6145,10 @@ export class Compiler extends DiagnosticEmitter {
         assert(!implicitNegate);
         return this.compileStaticString((<StringLiteralExpression>expression).value);
       }
-      // case LiteralKind.OBJECT:
+      case LiteralKind.OBJECT: {
+        assert(!implicitNegate);
+        return this.compileObjectLiteral(<ObjectLiteralExpression>expression, contextualType);
+      }
       // case LiteralKind.REGEXP:
     }
     this.error(
@@ -6392,6 +6396,88 @@ export class Compiler extends DiagnosticEmitter {
     }
   }
 
+  compileObjectLiteral(expression: ObjectLiteralExpression, contextualType: Type): ExpressionRef {
+    var module = this.module;
+
+    // contextual type must be a class
+    var classReference = contextualType.classReference;
+    if (!classReference || classReference.is(CommonFlags.ABSTRACT)) {
+      this.error(
+        DiagnosticCode.Type_0_is_not_assignable_to_type_1,
+        expression.range, "<object>", contextualType.toString()
+      );
+      return module.createUnreachable();
+    }
+
+    // if present, check that the constructor is compatible with object literals
+    var ctor = classReference.constructorInstance;
+    if (ctor) {
+      if (ctor.signature.requiredParameters) {
+        this.error(
+          DiagnosticCode.Constructor_of_class_0_must_not_require_any_arguments,
+          expression.range, classReference.toString()
+        );
+        return module.createUnreachable();
+      }
+      if (ctor.is(CommonFlags.PRIVATE)) {
+        this.error(
+          DiagnosticCode.Constructor_of_class_0_is_private_and_only_accessible_within_the_class_declaration,
+          expression.range, classReference.toString()
+        );
+        return module.createUnreachable();
+      }
+      if (ctor.is(CommonFlags.PROTECTED)) {
+        this.error(
+          DiagnosticCode.Constructor_of_class_0_is_protected_and_only_accessible_within_the_class_declaration,
+          expression.range, classReference.toString()
+        );
+        return module.createUnreachable();
+      }
+    }
+
+    // check and compile field values
+    var names = expression.names;
+    var numNames = names.length;
+    var values = expression.values;
+    var members = classReference.members;
+    var hasErrors = false;
+    var exprs = new Array<ExpressionRef>(numNames + 2);
+    var tempLocal = this.currentFunction.getTempLocal(this.options.usizeType);
+    assert(numNames == values.length);
+    for (let i = 0, k = numNames; i < k; ++i) {
+      let member = members ? members.get(names[i].text) : null;
+      if (!member || member.kind != ElementKind.FIELD) {
+        this.error(
+          DiagnosticCode.Property_0_does_not_exist_on_type_1,
+          names[i].range, names[i].text, classReference.toString()
+        );
+        hasErrors = true;
+        continue;
+      }
+      let type = (<Field>member).type;
+      exprs[i + 1] = this.module.createStore( // TODO: handle setters as well
+        type.byteSize,
+        this.module.createGetLocal(tempLocal.index, this.options.nativeSizeType),
+        this.compileExpression(values[i], (<Field>member).type, ConversionKind.IMPLICIT, WrapMode.NONE),
+        type.toNativeType(),
+        (<Field>member).memoryOffset
+      );
+    }
+    this.currentType = classReference.type.nonNullableType;
+    if (hasErrors) return module.createUnreachable();
+
+    // allocate a new instance first and assign 'this' to the temp. local
+    exprs[0] = module.createSetLocal(
+      tempLocal.index,
+      compileBuiltinAllocate(this, classReference, expression)
+    );
+
+    // once all field values have been set, return 'this'
+    exprs[exprs.length - 1] = module.createGetLocal(tempLocal.index, this.options.nativeSizeType);
+
+    return module.createBlock(null, exprs, this.options.nativeSizeType);
+  }
+
   compileNewExpression(expression: NewExpression, contextualType: Type): ExpressionRef {
     var module = this.module;
     var options = this.options;

src/common.ts

@@ -25,6 +25,7 @@ export enum DiagnosticCode {
   Duplicate_decorator = 213,
   An_allocator_must_be_declared_to_allocate_memory_Try_importing_allocator_arena_or_allocator_tlsf = 214,
   Optional_parameter_must_have_an_initializer = 215,
+  Constructor_of_class_0_must_not_require_any_arguments = 216,
   Unterminated_string_literal = 1002,
   Identifier_expected = 1003,
   _0_expected = 1005,
@@ -111,6 +112,8 @@ export enum DiagnosticCode {
   Expected_at_least_0_arguments_but_got_1 = 2555,
   Expected_0_type_arguments_but_got_1 = 2558,
   A_member_initializer_in_a_enum_declaration_cannot_reference_members_declared_after_it_including_members_defined_in_other_enums = 2651,
+  Constructor_of_class_0_is_private_and_only_accessible_within_the_class_declaration = 2673,
+  Constructor_of_class_0_is_protected_and_only_accessible_within_the_class_declaration = 2674,
   Namespace_0_has_no_exported_member_1 = 2694,
   File_0_not_found = 6054,
   Numeric_separators_are_not_allowed_here = 6188,
@@ -138,6 +141,7 @@ export function diagnosticCodeToString(code: DiagnosticCode): string {
     case 213: return "Duplicate decorator.";
     case 214: return "An allocator must be declared to allocate memory. Try importing allocator/arena or allocator/tlsf.";
     case 215: return "Optional parameter must have an initializer.";
+    case 216: return "Constructor of class '{0}' must not require any arguments.";
     case 1002: return "Unterminated string literal.";
     case 1003: return "Identifier expected.";
     case 1005: return "'{0}' expected.";
@@ -224,6 +228,8 @@ export function diagnosticCodeToString(code: DiagnosticCode): string {
     case 2555: return "Expected at least {0} arguments, but got {1}.";
     case 2558: return "Expected {0} type arguments, but got {1}.";
     case 2651: return "A member initializer in a enum declaration cannot reference members declared after it, including members defined in other enums.";
+    case 2673: return "Constructor of class '{0}' is private and only accessible within the class declaration.";
+    case 2674: return "Constructor of class '{0}' is protected and only accessible within the class declaration.";
     case 2694: return "Namespace '{0}' has no exported member '{1}'.";
     case 6054: return "File '{0}' not found.";
     case 6188: return "Numeric separators are not allowed here.";

src/compiler.ts

@@ -17,6 +17,7 @@
   "Duplicate decorator.": 213,
   "An allocator must be declared to allocate memory. Try importing allocator/arena or allocator/tlsf.": 214,
   "Optional parameter must have an initializer.": 215,
+  "Constructor of class '{0}' must not require any arguments.": 216,
 
   "Unterminated string literal.": 1002,
   "Identifier expected.": 1003,
@@ -105,6 +106,8 @@
   "Expected at least {0} arguments, but got {1}.": 2555,
   "Expected {0} type arguments, but got {1}.": 2558,
   "A member initializer in a enum declaration cannot reference members declared after it, including members defined in other enums.": 2651,
+  "Constructor of class '{0}' is private and only accessible within the class declaration.": 2673,
+  "Constructor of class '{0}' is protected and only accessible within the class declaration.": 2674,
   "Namespace '{0}' has no exported member '{1}'.": 2694,
 
   "File '{0}' not found.": 6054,

src/diagnosticMessages.generated.ts

@@ -39,6 +39,8 @@ import {
   UnaryPostfixExpression,
   UnaryExpression,
   UnaryPrefixExpression,
+  ClassExpression,
+  ObjectLiteralExpression,
 
   Statement,
   BlockStatement,
@@ -76,8 +78,7 @@ import {
   ParameterNode,
   ParameterKind,
   ExportMember,
-  SwitchCase,
-  ClassExpression
+  SwitchCase
 } from "../ast";
 
 import {
@@ -411,7 +412,8 @@ export class ASTBuilder {
   // expressions
 
   visitIdentifierExpression(node: IdentifierExpression): void {
-    this.sb.push(node.text);
+    if (node.is(CommonFlags.QUOTED)) this.visitStringLiteral(node.text);
+    else this.sb.push(node.text);
   }
 
   visitArrayLiteralExpression(node: ArrayLiteralExpression): void {
@@ -429,6 +431,33 @@ export class ASTBuilder {
     sb.push("]");
   }
 
+  visitObjectLiteralExpression(node: ObjectLiteralExpression): void {
+    var sb = this.sb;
+    var names = node.names;
+    var values = node.values;
+    var numElements = names.length;
+    assert(numElements == values.length);
+    if (numElements) {
+      sb.push("{\n");
+      indent(sb, ++this.indentLevel);
+      this.visitNode(names[0]);
+      sb.push(": ");
+      this.visitNode(values[0]);
+      for (let i = 1; i < numElements; ++i) {
+        sb.push(",\n");
+        indent(sb, this.indentLevel);
+        this.visitNode(names[i]);
+        sb.push(": ");
+        this.visitNode(values[i]);
+      }
+      sb.push("\n");
+      indent(sb, --this.indentLevel);
+      sb.push("}");
+    } else {
+      sb.push("{}");
+    }
+  }
+
   visitAssertionExpression(node: AssertionExpression): void {
     var sb = this.sb;
     if (node.assertionKind == AssertionKind.PREFIX) {
@@ -542,10 +571,10 @@ export class ASTBuilder {
         this.visitArrayLiteralExpression(<ArrayLiteralExpression>node);
         break;
       }
-      // case LiteralKind.OBJECT: {
-      //   this.serializeObjectLiteralExpression(<ObjectLiteralExpression>node);
-      //   break;
-      // }
+      case LiteralKind.OBJECT: {
+        this.visitObjectLiteralExpression(<ObjectLiteralExpression>node);
+        break;
+      }
       default: {
         assert(false);
         break;

src/diagnosticMessages.json

@@ -3073,6 +3073,51 @@ export class Parser extends DiagnosticEmitter {
         }
         return Node.createArrayLiteralExpression(elementExpressions, tn.range(startPos, tn.pos));
       }
+      // ObjectLiteralExpression
+      case Token.OPENBRACE: {
+        let startPos = tn.tokenPos;
+        let names = new Array<IdentifierExpression>();
+        let values = new Array<Expression>();
+        let name: IdentifierExpression;
+        while (!tn.skip(Token.CLOSEBRACE)) {
+          if (!tn.skipIdentifier()) {
+            if (!tn.skip(Token.STRINGLITERAL)) {
+              this.error(
+                DiagnosticCode.Identifier_expected,
+                tn.range(),
+              );
+              return null;
+            }
+            name = Node.createIdentifierExpression(tn.readString(), tn.range());
+            name.set(CommonFlags.QUOTED);
+          } else {
+            name = Node.createIdentifierExpression(tn.readIdentifier(), tn.range());
+          }
+          if (!tn.skip(Token.COLON)) {
+            this.error(
+              DiagnosticCode._0_expected,
+              tn.range(), ":"
+            );
+            return null;
+          }
+          let value = this.parseExpression(tn, Precedence.COMMA + 1);
+          if (!value) return null;
+          names.push(name);
+          values.push(value);
+          if (!tn.skip(Token.COMMA)) {
+            if (tn.skip(Token.CLOSEBRACE)) {
+              break;
+            } else {
+              this.error(
+                DiagnosticCode._0_expected,
+                tn.range(), "}"
+              );
+              return null;
+            }
+          }
+        }
+        return Node.createObjectLiteralExpression(names, values, tn.range(startPos, tn.pos));
+      }
       // AssertionExpression (unary prefix)
       case Token.LESSTHAN: {
         let toType = this.parseType(tn);