[Port] Forced re-execution expression within template (#1762)

* Forced re-execution expression within template

* retrigger ci

Author: Danieladu

libraries/botbuilder-lg/src/evaluator.ts

@@ -49,6 +49,7 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
     public static readonly fromFileFunctionName = 'fromFile';
     public static readonly templateFunctionName = 'template';
     public static readonly isTemplateFunctionName = 'isTemplate';
+    private static readonly ReExecuteSuffix = '!';
 
     public constructor(templates: LGTemplate[], expressionEngine: ExpressionEngine) {
         super();
@@ -65,11 +66,15 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
 
     /**
      * Evaluate a template with given name and scope.
-     * @param templateName template name.
+     * @param inputTemplateName template name.
      * @param scope scope.
      * @returns Evaluate result.
      */
-    public evaluateTemplate(templateName: string, scope: any): any {
+    public evaluateTemplate(inputTemplateName: string, scope: any): any {
+        let templateName: string;
+        let reExecute: boolean;
+        ({reExecute, pureTemplateName: templateName} = this.parseTemplateName(inputTemplateName));
+
         if (!(templateName in this.templateMap)) {
             throw new Error(`No such template: ${ templateName }`);
         }
@@ -91,7 +96,7 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
 
         if (this.evalutationTargetStack.length !== 0) {
             previousEvaluateTarget = this.evalutationTargetStack[this.evalutationTargetStack.length - 1];
-            if (previousEvaluateTarget.evaluatedChildren.has(currentEvulateId)) {
+            if (!reExecute && previousEvaluateTarget.evaluatedChildren.has(currentEvulateId)) {
                 return previousEvaluateTarget.evaluatedChildren.get(currentEvulateId);
             }
         }
@@ -236,7 +241,9 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
         }).join('');
     }
 
-    public constructScope(templateName: string, args: any[]): any {
+    public constructScope(inputTemplateName: string, args: any[]): any {
+        var templateName = this.parseTemplateName(inputTemplateName).pureTemplateName;
+
         if (!this.templateMap[templateName]) {
             throw new Error(`No such template ${ templateName }`);
         }
@@ -403,9 +410,10 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
             return baseLookup(name.substring(prebuiltPrefix.length));
         }
 
-        if (this.templateMap[name]) {
+        var templateName = this.parseTemplateName(name).pureTemplateName;
+        if (templateName in this.templateMap) {
             // tslint:disable-next-line: max-line-length
-            return new ExpressionEvaluator(name, ExpressionFunctions.apply(this.templateEvaluator(name)), ReturnType.Object, this.validTemplateReference);
+            return new ExpressionEvaluator(templateName, ExpressionFunctions.apply(this.templateEvaluator(name)), ReturnType.Object, this.validTemplateReference);
         }
 
         if (name === Evaluator.templateFunctionName) {
@@ -581,4 +589,16 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
             throw new Error(`arguments mismatch for template ${ templateName }, expect ${ expectedArgsCount } actual ${ actualArgsCount }`);
         }
     }
+
+    private parseTemplateName(templateName: string): { reExecute: boolean; pureTemplateName: string } {
+        if (!templateName) {
+            throw new Error('template name is empty.');
+        }
+
+        if (templateName.endsWith(Evaluator.ReExecuteSuffix)) {
+            return {reExecute:true, pureTemplateName: templateName.substr(0, templateName.length - Evaluator.ReExecuteSuffix.length)};
+        } else {
+            return {reExecute:false, pureTemplateName: templateName};
+        }
+    }
 }

libraries/botbuilder-lg/tests/lg.test.js

@@ -771,4 +771,11 @@ describe('LG', function() {
         evaled = LGFile.evaluateTemplate('T3', scope);
         assert.strictEqual(evaled, 'p1enum');
     });
+
+    it('TestReExecute', function() {
+        var LGFile = LGParser.parseFile(GetExampleFilePath('ReExecute.lg'));
+
+        // may be has different values
+        LGFile.evaluateTemplate('templateWithSameParams', {param1:'ms', param2:'newms'});
+    });
 });

libraries/botbuilder-lg/tests/testData/examples/ReExecute.lg

@@ -0,0 +1,9 @@
+# templateWithSameParams(param)
+- ${listTemplate1(param)} ${listTemplate1!(param)}
+
+# listTemplate1(param)
+- item1
+- item2
+- item3
+- item4
+- item5