Moved transpile switch to Lua 5.2 (#259)

lolleko · Perryvw · commit bab8df3e9916 · 2018-10-20T16:52:04.000+02:00
* Moved transpile switch to Lua 5.2 Closes #194 * Fixed typo
diff --git a/src/Transpiler.ts b/src/Transpiler.ts
@@ -615,75 +615,7 @@ export abstract class LuaTranspiler {
     }
 
     public transpileSwitch(node: ts.SwitchStatement): string {
-        const expression = this.transpileExpression(node.expression, true);
-        const clauses = node.caseBlock.clauses;
-
-        let result = this.indent + "-------Switch statement start-------\n";
-
-        const switchVarName = "____switch" + this.genVarCounter;
-        this.genVarCounter++;
-
-        result += this.indent + `local ${switchVarName} = ${expression}\n`;
-
-        let hasDefaultClause = false;
-
-        // If statement to go to right entry label
-        clauses.forEach((clause, index) => {
-            if (ts.isCaseClause(clause)) {
-                result += this.indent +
-                          `if ${this.transpileExpression(clause.expression, true)} == ${switchVarName} then\n`;
-
-                this.pushIndent();
-                result += this.indent + `goto ${switchVarName}_case_${index}\n`;
-                this.popIndent();
-
-                result += this.indent + "end\n";
-            } else if (ts.isDefaultClause(clause)) {
-                hasDefaultClause = true;
-            }
-        });
-
-        result += "\n";
-
-        // If no case condition is matched jump to end or default immediately
-        if (hasDefaultClause) {
-            result += this.indent + `goto ${switchVarName}_default\n`;
-        } else {
-            result += this.indent + `goto ${switchVarName}_end\n`;
-        }
-
-        result += "\n";
-
-        const transpileClauseBody = (clause: ts.CaseOrDefaultClause) => {
-            this.transpilingSwitch++;
-            result += this.indent + "do\n";
-            this.pushIndent();
-            result += this.transpileBlock(ts.createBlock(clause.statements));
-            this.popIndent();
-            result += this.indent + "end\n";
-            this.transpilingSwitch--;
-        };
-
-        clauses.forEach((clause, index) => {
-            if (ts.isCaseClause(clause)) {
-                result += this.indent + `::${switchVarName}_case_${index}::\n`;
-
-                transpileClauseBody(clause);
-
-                if (tsHelper.containsStatement(clause.statements, ts.SyntaxKind.BreakStatement)) {
-                    result += this.indent + `goto ${switchVarName}_end\n`;
-                }
-            } else if (ts.isDefaultClause(clause)) {
-                result += this.indent + `::${switchVarName}_default::\n`;
-
-                transpileClauseBody(clause);
-            }
-        });
-
-        result += this.indent + `::${switchVarName}_end::\n`;
-        result += this.indent + "-------Switch statement end-------\n";
-
-        return result;
+        throw TSTLErrors.UnsupportedForTarget("Switch statements", this.options.luaTarget, node);
     }
 
     public transpileTry(node: ts.TryStatement): string {
diff --git a/src/targets/Transpiler.52.ts b/src/targets/Transpiler.52.ts
@@ -59,6 +59,79 @@ export class LuaTranspiler52 extends LuaTranspiler51 {
         }
     }
 
+    /** @override */
+    public transpileSwitch(node: ts.SwitchStatement): string {
+        const expression = this.transpileExpression(node.expression, true);
+        const clauses = node.caseBlock.clauses;
+
+        let result = this.indent + "-------Switch statement start-------\n";
+
+        const switchVarName = "____switch" + this.genVarCounter;
+        this.genVarCounter++;
+
+        result += this.indent + `local ${switchVarName} = ${expression}\n`;
+
+        let hasDefaultClause = false;
+
+        // If statement to go to right entry label
+        clauses.forEach((clause, index) => {
+            if (ts.isCaseClause(clause)) {
+                result += this.indent +
+                          `if ${this.transpileExpression(clause.expression, true)} == ${switchVarName} then\n`;
+
+                this.pushIndent();
+                result += this.indent + `goto ${switchVarName}_case_${index}\n`;
+                this.popIndent();
+
+                result += this.indent + "end\n";
+            } else if (ts.isDefaultClause(clause)) {
+                hasDefaultClause = true;
+            }
+        });
+
+        result += "\n";
+
+        // If no case condition is matched jump to end or default immediately
+        if (hasDefaultClause) {
+            result += this.indent + `goto ${switchVarName}_default\n`;
+        } else {
+            result += this.indent + `goto ${switchVarName}_end\n`;
+        }
+
+        result += "\n";
+
+        const transpileClauseBody = (clause: ts.CaseOrDefaultClause) => {
+            this.transpilingSwitch++;
+            result += this.indent + "do\n";
+            this.pushIndent();
+            result += this.transpileBlock(ts.createBlock(clause.statements));
+            this.popIndent();
+            result += this.indent + "end\n";
+            this.transpilingSwitch--;
+        };
+
+        clauses.forEach((clause, index) => {
+            if (ts.isCaseClause(clause)) {
+                result += this.indent + `::${switchVarName}_case_${index}::\n`;
+
+                transpileClauseBody(clause);
+
+                if (tsHelper.containsStatement(clause.statements, ts.SyntaxKind.BreakStatement)) {
+                    result += this.indent + `goto ${switchVarName}_end\n`;
+                }
+            } else if (ts.isDefaultClause(clause)) {
+                result += this.indent + `::${switchVarName}_default::\n`;
+
+                transpileClauseBody(clause);
+            }
+        });
+
+        result += this.indent + `::${switchVarName}_end::\n`;
+        result += this.indent + "-------Switch statement end-------\n";
+
+        return result;
+    }
+
     /** @override */
     public transpileDestructingAssignmentValue(node: ts.Expression): string {
         return `table.unpack(${this.transpileExpression(node)})`;
diff --git a/test/unit/conditionals.spec.ts b/test/unit/conditionals.spec.ts
@@ -1,4 +1,6 @@
 import { Expect, Test, TestCase } from "alsatian";
+import { TranspileError } from "../../src/Errors";
+import { LuaTarget } from "../../src/Transpiler";
 import * as util from "../src/util";
 
 export class LuaConditionalsTests {
@@ -326,4 +328,10 @@ export class LuaConditionalsTests {
 
         Expect(result).toBe(5);
     }
+
+    @Test("switch not allowed in 5.1")
+    public switchThrow51(): void {
+        Expect( () => util.transpileString(`switch ("abc") {}`, {luaTarget: LuaTarget.Lua51}))
+            .toThrowError(TranspileError, "Switch statements is/are not supported for target Lua 5.1.");
+    }
 }
