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Cleaned up ForOf code #260

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Merged
Perryvw merged 3 commits into from
Oct 21, 2018
Merged

Cleaned up ForOf code #260

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5c38195
Cleaned up forOf loop, made it use numeric loop instead of ipairs
Perryvw Oct 20, 2018
93068f2
Fixed bug in non-array loop header and fixed tests
Perryvw Oct 20, 2018
50b4e94
Fixed up some PR comments
Perryvw Oct 21, 2018
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33 changes: 23 additions & 10 deletions src/Transpiler.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -558,28 +558,41 @@ export abstract class LuaTranspiler {
const variable = (node.initializer as ts.VariableDeclarationList).declarations[0];

// Transpile expression
const expression = this.transpileExpression(node.expression);
const iterable = this.transpileExpression(node.expression);

// Use ipairs for array types, pairs otherwise
const isArray = tsHelper.isArrayType(this.checker.getTypeAtLocation(node.expression), this.checker);
const pairs = isArray ? "ipairs" : "pairs";

// Make header
let result = "";
if (ts.isIdentifier(variable.name)) {
result = this.indent + `for _, ${this.transpileIdentifier(variable.name)} in ${pairs}(${expression}) do\n`;
} else if (ts.isArrayBindingPattern(variable.name)) {
const valueVar = "__forOfValue" + this.genVarCounter;
result = this.indent + `for _, ${valueVar} in ${pairs}(${expression}) do\n`;
const declaration = ts.createVariableDeclaration(variable.name, undefined, ts.createIdentifier(valueVar));
result += this.indent + this.transpileVariableDeclaration(declaration);

if (!isArray && ts.isIdentifier(variable.name)) {
result = this.indent + `for _, ${this.transpileIdentifier(variable.name)} in pairs(${iterable}) do\n`;
} else {
let itemVariable: ts.Identifier;
if (isArray) {
// Cache the expression result
result += this.indent + `local __loopVariable${this.genVarCounter} = ${iterable};\n`;
result += this.indent + `for i${this.genVarCounter}=1, #__loopVariable${this.genVarCounter} do\n`;
itemVariable = ts.createIdentifier(`__loopVariable${this.genVarCounter}[i${this.genVarCounter}]`);
} else {
const variableName = `__forOfValue${this.genVarCounter}`;
itemVariable = ts.createIdentifier(variableName);
result += this.indent + `for _, ${variableName} in pairs(${iterable}) do\n`;
}

const declaration = ts.createVariableDeclaration(variable.name, undefined, itemVariable);
this.pushIndent();
result += this.indent + this.transpileVariableDeclaration(declaration) + ";\n";
this.popIndent();
}

// For body
this.pushIndent();
result += this.transpileLoopBody(node);
this.popIndent();

this.genVarCounter++;

return result + this.indent + "end\n";
}

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4 changes: 3 additions & 1 deletion test/translation/lua/forOf.lua
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@@ -1,4 +1,6 @@
for _, i in ipairs({1,2,3,4,5,6,7,8,9,10}) do
local __loopVariable0 = {1,2,3,4,5,6,7,8,9,10};
for i0=1, #__loopVariable0 do
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@lolleko lolleko Oct 20, 2018 •
edited
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Just realized that using # operator is unsafe. Not sure if this applies only to this part of the transpiler or to other parts aswell.

If you do

local x = {1,2}
x[5] = 12
print(#x)

The result is undefined because the array has gaps, i got 2 as result when running in https://www.lua.org/cgi-bin/demo

var arr = [1, 2];
arr[5] = 12;
console.log(arr.length);

However returns 6 as "expected".

local i = __loopVariable0[i0];
do
end
::__continue0::
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20 changes: 20 additions & 0 deletions test/unit/loops.spec.ts
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Expand Up @@ -286,6 +286,26 @@ export class LuaLoopTests {
Expect(result).toBe(JSON.stringify(expected));
}

@TestCase([[1, 2], [2, 3], [3, 4]], [3, 5, 7])
@Test("forof destructing")
public forofDestructing(inp: number[][], expected: any): void {
// Transpile
const lua = util.transpileString(
`let objTest = ${JSON.stringify(inp)};
let arrResultTest = [];
for (let [a,b] of objTest) {
arrResultTest.push(a + b)
}
return JSONStringify(arrResultTest);`
);

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

// Assert
Expect(result).toBe(JSON.stringify(expected));
}

@TestCase([0, 1, 2, 3, 4], [0, 0, 2, 0, 4])
@Test("forof with continue")
public forofWithContinue(inp: number[], expected: number[]): void {
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