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Merged
Perryvw merged 3 commits into from
Oct 13, 2018
Merged

-added support for class expressions #236

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4890353
-added support for class expressions
Oct 13, 2018
3969134
-minor refactor
Oct 13, 2018
c31c11f
-test for base class method calling when using class expression
Oct 13, 2018
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2 changes: 1 addition & 1 deletion src/TSHelper.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ export class TSHelper {
return statements.some(statement => statement.kind === kind);
}

public static getExtendedType(node: ts.ClassDeclaration, checker: ts.TypeChecker): ts.Type | undefined {
public static getExtendedType(node: ts.ClassLikeDeclarationBase, checker: ts.TypeChecker): ts.Type | undefined {
if (node && node.heritageClauses) {
for (const clause of node.heritageClauses) {
if (clause.token === ts.SyntaxKind.ExtendsKeyword) {
Expand Down
19 changes: 11 additions & 8 deletions src/Transpiler.ts
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Expand Up @@ -805,6 +805,11 @@ export abstract class LuaTranspiler {
return this.transpileSpreadElement(node as ts.SpreadElement);
case ts.SyntaxKind.NonNullExpression:
return this.transpileExpression((node as ts.NonNullExpression).expression);
case ts.SyntaxKind.ClassExpression:
this.namespace.push("");
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@Perryvw Perryvw Oct 13, 2018

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Any specific reason for this line?

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@andreiradu andreiradu Oct 13, 2018

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It scopes the class declaration. Otherwise the class would be in global scope. Not sure if this is the best approach - I see it as sort of an anonymous namespace in C++.

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@Perryvw Perryvw Oct 13, 2018

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Could you provide an input/ouput example?

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@andreiradu andreiradu Oct 13, 2018

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let f = function() { let a = class{} }
would generate
local f; f = function() local a = (function() --[[ should be local ]] _ = _ or {} _.__index = _ function _.new(construct, ...) local self = setmetatable({}, _) if construct and _.constructor then _.constructor(self, ...) end return self end function _.constructor(self) end ; return _ end)(); end ;

const classDeclaration = this.transpileClass(node as ts.ClassExpression, "_");
this.namespace.pop();
return `(function() ${classDeclaration}; return _ end)()`;
case ts.SyntaxKind.Block:
this.pushIndent();
const ret = "do \n" + this.transpileBlock(node as ts.Block) + "end\n";
Expand Down Expand Up @@ -1596,13 +1601,12 @@ export abstract class LuaTranspiler {
}

// Transpile a class declaration
public transpileClass(node: ts.ClassDeclaration): string {
if (!node.name) {
public transpileClass(node: ts.ClassLikeDeclarationBase, nameOverride?: string): string {
let className = node.name ? this.transpileIdentifier(node.name) : nameOverride;
if (!className) {
throw TSTLErrors.MissingClassName(node);
}

let className = this.transpileIdentifier(node.name);

const decorators = tsHelper.getCustomDecorators(this.checker.getTypeAtLocation(node), this.checker);

// Find out if this class is extension of existing class
Expand Down Expand Up @@ -1648,7 +1652,7 @@ export abstract class LuaTranspiler {
}

if (!isExtension && !isMetaExtension) {
result += this.transpileClassCreationMethods(node, instanceFields, extendsType);
result += this.transpileClassCreationMethods(node, className, instanceFields, extendsType);
} else {
for (const f of instanceFields) {
// Get identifier
Expand Down Expand Up @@ -1697,10 +1701,9 @@ export abstract class LuaTranspiler {
return result;
}

public transpileClassCreationMethods(node: ts.ClassDeclaration, instanceFields: ts.PropertyDeclaration[],
public transpileClassCreationMethods(node: ts.ClassLikeDeclarationBase, className: string,
instanceFields: ts.PropertyDeclaration[],
extendsType: ts.Type): string {
const className = this.transpileIdentifier(node.name);

let noClassOr = false;
if (extendsType) {
const decorators = tsHelper.getCustomDecorators(extendsType, this.checker);
Expand Down
43 changes: 43 additions & 0 deletions test/unit/class.spec.ts
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Expand Up @@ -429,4 +429,47 @@ export class ClassTests {
// Assert
Expect(result).toBe(10);
}
@Test("classExpression")
public classExpression(): void {
const lua = util.transpileString(
`class a {
public method() {
return "instance of a";
}
}
b = class extends a {
public method() {
return "instance of b";
}
}
let inst = new b(6);
return inst.method();`
);

// Execute
const result = util.executeLua(lua);

// Assert
Expect(result).toBe("instance of b");
}
@Test("classExpressionBaseClassMethod")
public classExpressionBaseClassMethod(): void {
const lua = util.transpileString(
`class a {
public method() {
return 42;
}
}
b = class extends a {
}
let inst = new b();
return inst.method();`
);

// Execute
const result = util.executeLua(lua);

// Assert
Expect(result).toBe(42);
}
}