Use lua's math.atan2 for Math.atan2 (#765)

hazzard993 · ark120202 · Perryvw · commit 10ff5f73f789 · 2019-12-18T20:42:22.000+01:00
* use lua's math.atan2 for Math.atan2

* use math.atan for Lua 5.3

* use snapshots for tests

* use tap and testEachVersion for math.atan testing

* Move Math.atan2 transformation down to switch case

* Move math atan2 transformation back to top of switch

* Remove unneeded whitespace change

* Improve math.atan2 comment

Co-Authored-By: Perry van Wesel &lt;Perryvw@users.noreply.github.com&gt;

* Use methodName for Math method transformation

* Add Math.atan2 Lua5.3 comparison test, fix math.atan taps

* Update test/unit/builtins/math.spec.ts

Co-Authored-By: ark120202 &lt;ark120202@gmail.com&gt;

* Update test/unit/builtins/math.spec.ts

Co-Authored-By: ark120202 &lt;ark120202@gmail.com&gt;
diff --git a/src/transformation/builtins/math.ts b/src/transformation/builtins/math.ts
@@ -1,5 +1,6 @@
 import * as ts from "typescript";
 import * as lua from "../../LuaAST";
+import { LuaTarget } from "../../CompilerOptions";
 import { TransformationContext } from "../context";
 import { UnsupportedProperty } from "../utils/errors";
 import { PropertyCallExpression, transformArguments } from "../visitors/call";
@@ -33,12 +34,13 @@ export function transformMathCall(context: TransformationContext, node: Property
 
     const expressionName = expression.name.text;
     switch (expressionName) {
-        // math.tan(x / y)
+        // Lua 5.3: math.atan(y, x)
+        // Otherwise: math.atan2(y, x)
         case "atan2": {
             const math = lua.createIdentifier("math");
-            const atan = lua.createStringLiteral("atan");
-            const div = lua.createBinaryExpression(params[0], params[1], lua.SyntaxKind.DivisionOperator);
-            return lua.createCallExpression(lua.createTableIndexExpression(math, atan), [div], node);
+            const methodName = context.options.luaTarget === LuaTarget.Lua53 ? "atan" : expressionName;
+            const method = lua.createStringLiteral(methodName);
+            return lua.createCallExpression(lua.createTableIndexExpression(math, method), params, node);
         }
 
         // (math.log(x) / Math.LNe)
diff --git a/test/unit/builtins/__snapshots__/math.spec.ts.snap b/test/unit/builtins/__snapshots__/math.spec.ts.snap
@@ -8,14 +8,6 @@ end
 return ____exports"
 `;
 
-exports[`Math.atan2(2, 3) 1`] = `
-"local ____exports = {}
-function ____exports.__main(self)
-    math.atan(2 / 3)
-end
-return ____exports"
-`;
-
 exports[`Math.cos() 1`] = `
 "local ____exports = {}
 function ____exports.__main(self)
diff --git a/test/unit/builtins/math.spec.ts b/test/unit/builtins/math.spec.ts
@@ -1,10 +1,10 @@
+import * as tstl from "../../../src";
 import * as util from "../../util";
 
 test.each([
     "Math.cos()",
     "Math.sin()",
     "Math.min()",
-    "Math.atan2(2, 3)",
     "Math.log2(3)",
     "Math.log10(3)",
     "const x = Math.log2(3)",
@@ -24,3 +24,17 @@ test.each(["E", "LN10", "LN2", "LOG10E", "LOG2E", "SQRT1_2", "SQRT2"])("Math.%s"
         expect(builder.getLuaExecutionResult()).toBeCloseTo(builder.getJsExecutionResult());
     });
 });
+
+const expectMathAtan2: util.TapCallback = builder => expect(builder.getMainLuaCodeChunk()).toContain("math.atan2(");
+const expectMathAtan: util.TapCallback = builder => expect(builder.getMainLuaCodeChunk()).toContain("math.atan(");
+
+util.testEachVersion("Math.atan2", () => util.testExpression`Math.atan2(4, 5)`, {
+    [tstl.LuaTarget.LuaJIT]: builder => builder.tap(expectMathAtan2),
+    [tstl.LuaTarget.Lua51]: builder => builder.tap(expectMathAtan2),
+    [tstl.LuaTarget.Lua52]: builder => builder.tap(expectMathAtan2),
+    [tstl.LuaTarget.Lua53]: builder => builder.tap(expectMathAtan),
+});
+
+test("Math.atan2(4, 5)", () => {
+    util.testExpression`Math.atan2(4, 5)`.expectToMatchJsResult();
+});
