${} instead of @{} as bounding syntax.

libraries/botbuilder-lg/README.MD

@@ -12,9 +12,9 @@ Language generation is achieved through:
 
 ```markdown
 # greetingTemplate
-- Hello @{user.name}, how are you?
-- Good morning @{user.name}. It's nice to see you again.
-- Good day @{user.name}. What can I do for you today?
+- Hello ${user.name}, how are you?
+- Good morning ${user.name}. It's nice to see you again.
+- Good day ${user.name}. What can I do for you today?
 ```
 
 You can use language generation to:
@@ -33,15 +33,15 @@ Example here:
 ```markdown
     # HeroCardTemplate(buttonsCollection)
     [Herocard
-        title=@{TitleText())}
-        subtitle=@{SubText())}
-        text=@{DescriptionText())}
-        images=@{CardImages())}
-        buttons=@{buttonsCollection}
+        title=${TitleText())}
+        subtitle=${SubText())}
+        text=${DescriptionText())}
+        images=${CardImages())}
+        buttons=${buttonsCollection}
     ]
 
     # TitleText
-    - Here are some @{TitleSuffix()}
+    - Here are some ${TitleSuffix()}
 
     # TitleSuffix
     - cool photos

libraries/botbuilder-lg/src/LGFileLexer.g4

@@ -44,14 +44,14 @@ fragment EMPTY_OBJECT: '{' WHITESPACE* '}';
 
 fragment STRING_LITERAL : ('\'' (~['\r\n])* '\'') | ('"' (~["\r\n])* '"');
 
-fragment EXPRESSION_FRAGMENT : '@' '{' (STRING_LITERAL| ~[\r\n{}'"] | EMPTY_OBJECT )*? '}';
+fragment EXPRESSION_FRAGMENT : '$' '{' (STRING_LITERAL| ~[\r\n{}'"] | EMPTY_OBJECT )*? '}';
 
 fragment ESCAPE_CHARACTER_FRAGMENT : '\\' ~[\r\n]?;
 
 
 // top level elements
 COMMENTS
-  : ('>'|'$') ~('\r'|'\n')+ -> skip
+  : '>' ~('\r'|'\n')+ -> skip
   ;
 
 WS
@@ -205,7 +205,7 @@ TEXT_IN_STRUCTURE_NAME
 mode STRUCTURE_BODY_MODE;
 
 STRUCTURED_COMMENTS
-  : ('>'|'$') ~[\r\n]* '\r'?'\n' { !this.inStructuredValue && this.beginOfStructureProperty}? -> skip
+  : '>' ~[\r\n]* '\r'?'\n' { !this.inStructuredValue && this.beginOfStructureProperty}? -> skip
   ;
 
 WS_IN_STRUCTURE_BODY

libraries/botbuilder-lg/src/analyzer.ts

@@ -207,7 +207,7 @@ export class Analyzer extends AbstractParseTreeVisitor<AnalyzerResult> implement
 
     private analyzeExpression(exp: string): AnalyzerResult {
         const result: AnalyzerResult =  new AnalyzerResult();
-        exp = exp.replace(/(^@*)/g, '')
+        exp = exp.replace(/(^\$*)/g, '')
             .replace(/(^{*)/g, '')
             .replace(/(}*$)/g, '');
         const parsed: Expression = this._expressionParser.parse(exp);

libraries/botbuilder-lg/src/evaluator.ts

@@ -32,7 +32,7 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
 
     // to support broswer, use look-ahead replace look-behind
     // original:/(?<!\\)@\{((\'[^\'\r\n]*\')|(\"[^\"\r\n]*\")|[^\r\n\{\}\'\"])*?\}/g;
-    public static readonly expressionRecognizeReverseRegex: RegExp = new RegExp(/\}((\'[^\'\r\n]*\')|(\"[^\"\r\n]*\")|([^\r\n\{\}\'\"]))*?\{@(?!\\)/g);
+    public static readonly expressionRecognizeReverseRegex: RegExp = new RegExp(/\}((\'[^\'\r\n]*\')|(\"[^\"\r\n]*\")|([^\r\n\{\}\'\"]))*?\{\$(?!\\)/g);
 
     public static readonly LGType = 'lgType';
     public static readonly activityAttachmentFunctionName = 'ActivityAttachment';
@@ -311,7 +311,7 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
 
     private evalExpressionInCondition(exp: string): boolean {
         try {
-            exp = exp.replace(/(^@*)/g, '')
+            exp = exp.replace(/(^\$*)/g, '')
                 .replace(/(^{*)/g, '')
                 .replace(/(}*$)/g, '');
 
@@ -330,7 +330,7 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGFilePa
     }
 
     private evalExpression(exp: string): any {
-        exp = exp.replace(/(^@*)/g, '')
+        exp = exp.replace(/(^\$*)/g, '')
             .replace(/(^{*)/g, '')
             .replace(/(}*$)/g, '');
 

libraries/botbuilder-lg/src/expander.ts

@@ -307,7 +307,7 @@ export class Expander extends AbstractParseTreeVisitor<string[]> implements LGFi
 
     private evalExpressionInCondition(exp: string): boolean {
         try {
-            exp = exp.replace(/(^@*)/g, '')
+            exp = exp.replace(/(^\$*)/g, '')
                 .replace(/(^{*)/g, '')
                 .replace(/(}*$)/g, '');
 
@@ -326,7 +326,7 @@ export class Expander extends AbstractParseTreeVisitor<string[]> implements LGFi
     }
 
     private evalExpression(exp: string): string[] {
-        exp = exp.replace(/(^@*)/g, '')
+        exp = exp.replace(/(^\$*)/g, '')
             .replace(/(^{*)/g, '')
             .replace(/(}*$)/g, '');
 

libraries/botbuilder-lg/src/generated/LGFileParser.ts

@@ -1,4 +1,4 @@
-// Generated from LGFileParser.g4 by ANTLR 4.6-SNAPSHOT
+// Generated from ../LGFileParser.g4 by ANTLR 4.6-SNAPSHOT
 
 
 import { ATN } from "antlr4ts/atn/ATN";

libraries/botbuilder-lg/src/generated/LGFileParserListener.ts

@@ -1,4 +1,4 @@
-// Generated from LGFileParser.g4 by ANTLR 4.6-SNAPSHOT
+// Generated from ../LGFileParser.g4 by ANTLR 4.6-SNAPSHOT
 
 
 import { ParseTreeListener } from "antlr4ts/tree/ParseTreeListener";

libraries/botbuilder-lg/src/generated/LGFileParserVisitor.ts

@@ -1,4 +1,4 @@
-// Generated from LGFileParser.g4 by ANTLR 4.6-SNAPSHOT
+// Generated from ../LGFileParser.g4 by ANTLR 4.6-SNAPSHOT
 
 
 import { ParseTreeVisitor } from "antlr4ts/tree/ParseTreeVisitor";

libraries/botbuilder-lg/src/staticChecker.ts

@@ -372,7 +372,7 @@ class StaticCheckerInner extends AbstractParseTreeVisitor<Diagnostic[]> implemen
 
     private checkExpression(exp: string, context: ParserRuleContext): Diagnostic[] {
         const result: Diagnostic[] = [];
-        exp = exp.replace(/(^@*)/g, '')
+        exp = exp.replace(/(^\$*)/g, '')
             .replace(/(^{*)/g, '')
             .replace(/(}*$)/g, '')
             .trim();

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

@@ -151,12 +151,12 @@ describe('LG', function() {
         assert.strictEqual(emptyEngine.evaluate('Hi'), 'Hi', emptyEngine.evaluate('Hi'));
         assert.strictEqual(emptyEngine.evaluate('Hi', ''), 'Hi', emptyEngine.evaluate('Hi', ''));
 
-        assert.strictEqual(emptyEngine.evaluate('Hi @{name}', { name: 'DL' }), 'Hi DL');
+        assert.strictEqual(emptyEngine.evaluate('Hi ${name}', { name: 'DL' }), 'Hi DL');
 
-        assert.strictEqual(emptyEngine.evaluate('Hi @{name.FirstName}@{name.LastName}', { name: { FirstName: 'D', LastName: 'L' } }), 'Hi DL');
+        assert.strictEqual(emptyEngine.evaluate('Hi ${name.FirstName}${name.LastName}', { name: { FirstName: 'D', LastName: 'L' } }), 'Hi DL');
         assert.strictEqual(emptyEngine.evaluate('Hi \n Hello', ''), 'Hi \n Hello');
         assert.strictEqual(emptyEngine.evaluate('Hi \r\n Hello', ''), 'Hi \r\n Hello');
-        assert.strictEqual(emptyEngine.evaluate('Hi \r\n @{name}', { name: 'DL' }), 'Hi \r\n DL');
+        assert.strictEqual(emptyEngine.evaluate('Hi \r\n ${name}', { name: 'DL' }), 'Hi \r\n DL');
         assert.strictEqual(new TemplateEngine().evaluate('Hi', ''), 'Hi');
     });
 
@@ -165,11 +165,11 @@ describe('LG', function() {
         assert.strictEqual(emptyEngine.evaluate('Hi'), 'Hi', emptyEngine.evaluate('Hi'));
         assert.strictEqual(emptyEngine.evaluate('Hi', ''), 'Hi', emptyEngine.evaluate('Hi', ''));
 
-        assert.strictEqual(emptyEngine.evaluate('Hi @{name}', { name: 'DL' }), 'Hi DL', emptyEngine.evaluate('Hi @{name}', { name: 'DL' }));
+        assert.strictEqual(emptyEngine.evaluate('Hi ${name}', { name: 'DL' }), 'Hi DL', emptyEngine.evaluate('Hi ${name}', { name: 'DL' }));
 
-        assert.strictEqual(emptyEngine.evaluate('Hi @{name.FirstName}@{name.LastName} @{RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' } }), 'Hi DL You don\'t have any tasks.', emptyEngine.evaluate('Hi @{name.FirstName}@{name.LastName} @{RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' } }));
+        assert.strictEqual(emptyEngine.evaluate('Hi ${name.FirstName}${name.LastName} ${RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' } }), 'Hi DL You don\'t have any tasks.', emptyEngine.evaluate('Hi ${name.FirstName}${name.LastName} ${RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' } }));
 
-        assert.strictEqual(emptyEngine.evaluate('Hi @{name.FirstName}@{name.LastName} @{RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' }, recentTasks: ['task1'] }), 'Hi DL Your most recent task is task1. You can let me know if you want to add or complete a task.', emptyEngine.evaluate('Hi @{name.FirstName}@{name.LastName} @{RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' }, recentTasks: ['task1'] }));
+        assert.strictEqual(emptyEngine.evaluate('Hi ${name.FirstName}${name.LastName} ${RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' }, recentTasks: ['task1'] }), 'Hi DL Your most recent task is task1. You can let me know if you want to add or complete a task.', emptyEngine.evaluate('Hi ${name.FirstName}${name.LastName} ${RecentTasks()}', { name: { FirstName: 'D', LastName: 'L' }, recentTasks: ['task1'] }));
 
     });
 
@@ -646,7 +646,7 @@ describe('LG', function() {
         }
 
         evaled = engine.evaluateTemplate('AskForAge.prompt3');
-        assert.deepStrictEqual(evaled, JSON.parse('{"lgType":"Activity","text":"@{GetAge()}","suggestions":["10 | cards","20 | cards"]}'));
+        assert.deepStrictEqual(evaled, JSON.parse('{"lgType":"Activity","text":"${GetAge()}","suggestions":["10 | cards","20 | cards"]}'));
 
         evaled = engine.evaluateTemplate('T1');
         assert.deepStrictEqual(evaled, JSON.parse('{"lgType":"Activity","text":"This is awesome","speak":"foo bar I can also speak!"}'));

libraries/botbuilder-lg/tests/testData/adaptiveCard.json

@@ -5,7 +5,7 @@
     "body": [
         {
             "type": "TextBlock",
-            "text": "@{adaptiveCardTitle}",
+            "text": "${adaptiveCardTitle}",
             "weight": "bolder",
             "size": "medium"
         },

libraries/botbuilder-lg/tests/testData/examples/3.lg

@@ -8,6 +8,6 @@
 > Using a template in another template
 > Sometimes the bot will say 'Hi' and other times it will say 'Hi :)'
 # welcome-user()
-- @{wPhrase()}
-- @{wPhrase()} :)
+- ${wPhrase()}
+- ${wPhrase()} :)
 

libraries/botbuilder-lg/tests/testData/examples/4.lg

@@ -8,10 +8,10 @@
 > Using a template in another template
 > Sometimes the bot will say 'Hi' and other times it will say 'Hi :)'
 # welcome
-- @{wPhrase()}
-- @{wPhrase()} :)
+- ${wPhrase()}
+- ${wPhrase()} :)
 
 > Using entity references. Unless explicitly specified, entities default to string. Valid types are String, Int, Long, Float, Double, Bool, DateTime
 # welcome-user
-- @{wPhrase()} @{userName}
-- @{wPhrase()} @{userName} :)
+- ${wPhrase()} ${userName}
+- ${wPhrase()} ${userName} :)

libraries/botbuilder-lg/tests/testData/examples/5.lg

@@ -8,19 +8,19 @@
 > Using a template in another template
 > Sometimes the bot will say 'Hi' and other times it will say 'Hi :)'
 # welcome-user
-- @{wPhrase()}
-- @{wPhrase()} :)
+- ${wPhrase()}
+- ${wPhrase()} :)
 
 > Using entity references
 # welcome-user2
-- @{wPhrase()}
-- @{wPhrase()} @{userName}
-- @{wPhrase()} @{userName} :)
+- ${wPhrase()}
+- ${wPhrase()} ${userName}
+- ${wPhrase()} ${userName} :)
 
 > Conditional response template
 > Outer list is condition expression; L2 list is one-of collection
 # time-of-day-readout
-- IF: @{timeOfDay == 'morning'}
+- IF: ${timeOfDay == 'morning'}
     - Good morning
     - Morning! 
 - ELSE:
@@ -30,16 +30,16 @@
 > Conditional response template
 > Outer list is condition expression; L2 list is one-of collection
 # time-of-day-readout-without-default
-- IF: @{timeOfDay == 'morning'}
+- IF: ${timeOfDay == 'morning'}
     - Good morning
     - Morning! 
-- ELSEIF: @{timeOfDay != 'morning'}
+- ELSEIF: ${timeOfDay != 'morning'}
     - Good evening
     - Evening! 
 
 > Conditional response template
 > Outer list is condition expression; L2 list is one-of collection
 # time-of-day-readout-without-default2
-- IF: @{timeOfDay == 'morning'}
+- IF: ${timeOfDay == 'morning'}
     - Good morning
     - Morning! 

libraries/botbuilder-lg/tests/testData/examples/6.lg

@@ -8,40 +8,40 @@
 > Using a template in another template
 > Sometimes the bot will say 'Hi' and other times it will say 'Hi :)'
 # welcome-user(userName)
-- @{wPhrase()} @{userName} :)
+- ${wPhrase()} ${userName} :)
 
 > Using entity references
 # welcome
-- IF: @{userName}
-    - @{welcome-user(userName)}
+- IF: ${userName}
+    - ${welcome-user(userName)}
 - ELSE:
-    - @{welcome-user('DongLei')}
+    - ${welcome-user('DongLei')}
 
 
 
 # ShowAlarm(alarm)
-- @{alarm.time} at @{alarm.date}
+- ${alarm.time} at ${alarm.date}
 
 # ShowAlarmsWithForeach
-- IF: @{count(alarms) == 1}
-   - You have one alarm @{ShowAlarm(alarms[0])}
-- ELSEIF: @{count(alarms) == 2}
-  - You have @{count(alarms)} alarms, @{join(foreach(alarms, x, ShowAlarm(x)), ', ', ' and ')}
+- IF: ${count(alarms) == 1}
+   - You have one alarm ${ShowAlarm(alarms[0])}
+- ELSEIF: ${count(alarms) == 2}
+  - You have ${count(alarms)} alarms, ${join(foreach(alarms, x, ShowAlarm(x)), ', ', ' and ')}
 - ELSE:
   - You don't have any alarms
 
 # ShowAlarmsWithLgTemplate
-- IF: @{count(alarms) == 1}
-   - You have one alarm @{ShowAlarm(alarms[0])}
-- ELSEIF: @{count(alarms) == 2}
-  - You have @{count(alarms)} alarms, @{join(foreach(alarms, x, template('ShowAlarm', x)), ', ', ' and ')}
+- IF: ${count(alarms) == 1}
+   - You have one alarm ${ShowAlarm(alarms[0])}
+- ELSEIF: ${count(alarms) == 2}
+  - You have ${count(alarms)} alarms, ${join(foreach(alarms, x, template('ShowAlarm', x)), ', ', ' and ')}
 - ELSE:
   - You don't have any alarms
 
 # ShowAlarmsWithDynamicLgTemplate(templateName)
-- IF: @{count(alarms) == 1}
-   - You have one alarm @{ShowAlarm(alarms[0])}
-- ELSEIF: @{count(alarms) == 2}
-  - You have @{count(alarms)} alarms, @{join(foreach(alarms, x, template(templateName, x)), ', ', ' and ')}
+- IF: ${count(alarms) == 1}
+   - You have one alarm ${ShowAlarm(alarms[0])}
+- ELSEIF: ${count(alarms) == 2}
+  - You have ${count(alarms)} alarms, ${join(foreach(alarms, x, template(templateName, x)), ', ', ' and ')}
 - ELSE:
   - You don't have any alarms

libraries/botbuilder-lg/tests/testData/examples/8.lg

@@ -1,12 +1,12 @@
 # RecentTasks
-- IF: @{count(recentTasks) == 1}
-    - Your most recent task is @{recentTasks[0]}. You can let me know if you want to add or complete a task.
-- ELSEIF: @{count(recentTasks) == 2}
-    - Your most recent tasks are @{join(recentTasks, ',', 'and')}. You can let me know if you want to add or complete a task.
-- ELSEIF: @{count(recentTasks) > 2}
-    - Your most recent @{count(recentTasks)} tasks are @{join(recentTasks, ',', 'and')}. You can let me know if you want to add or complete a task.
+- IF: ${count(recentTasks) == 1}
+    - Your most recent task is ${recentTasks[0]}. You can let me know if you want to add or complete a task.
+- ELSEIF: ${count(recentTasks) == 2}
+    - Your most recent tasks are ${join(recentTasks, ',', 'and')}. You can let me know if you want to add or complete a task.
+- ELSEIF: ${count(recentTasks) > 2}
+    - Your most recent ${count(recentTasks)} tasks are ${join(recentTasks, ',', 'and')}. You can let me know if you want to add or complete a task.
 - ELSE:
     - You don't have any tasks.
 
 # ShowTasks
-- @{RecentTasks()}
+- ${RecentTasks()}

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

@@ -7,7 +7,7 @@
   "body": [
     {
       "type": "TextBlock",
-      "text": "@{adaptiveCardTitle}",
+      "text": "${adaptiveCardTitle}",
       "weight": "bolder",
       "size": "medium"
     },