Merge pull request #3899 from microsoft/hond/lambda

[Expression] Support lambda style expression
microsoft · Jun 14, 2020 · 2f0e402 · 2f0e402
2 parents 2963d0d + 0e63364
commit 2f0e402
Show file tree

Hide file tree

Showing 4 changed files with 34 additions and 7 deletions.
diff --git a/libraries/AdaptiveExpressions/parser/ExpressionAntlrLexer.g4 b/libraries/AdaptiveExpressions/parser/ExpressionAntlrLexer.g4
@@ -65,6 +65,8 @@ COMMA: ',';
 
 COLON: ':';
 
+ARROW: '=>';
+
 NUMBER : DIGIT + ( '.' DIGIT +)? ;
 
 WHITESPACE : (' '|'\t'|'\ufeff'|'\u00a0') {ignoreWS}? -> skip;

diff --git a/libraries/AdaptiveExpressions/parser/ExpressionAntlrParser.g4 b/libraries/AdaptiveExpressions/parser/ExpressionAntlrParser.g4
@@ -42,7 +42,11 @@ textContent
     ;
 
 argsList
-    : expression (COMMA expression)*
+    : (lambda|expression) (COMMA (lambda|expression))*
+    ;
+
+lambda
+    : IDENTIFIER ARROW expression
     ;
 
 keyValuePairList

diff --git a/libraries/AdaptiveExpressions/parser/ExpressionParser.cs b/libraries/AdaptiveExpressions/parser/ExpressionParser.cs
@@ -113,7 +113,7 @@ public override Expression VisitBinaryOpExp([NotNull] ExpressionAntlrParser.Bina
 
             public override Expression VisitFuncInvokeExp([NotNull] ExpressionAntlrParser.FuncInvokeExpContext context)
             {
-                var parameters = ProcessArgsList(context.argsList()).ToList();
+                var parameters = ProcessArgsList(context.argsList());
 
                 // Remove the check to check primaryExpression is just an IDENTIFIER to support "." in template name
                 var functionName = context.primaryExpression().GetText();
@@ -191,7 +191,7 @@ public override Expression VisitNumericAtom([NotNull] ExpressionAntlrParser.Nume
 
             public override Expression VisitArrayCreationExp([NotNull] ExpressionAntlrParser.ArrayCreationExpContext context)
             {
-                var parameters = ProcessArgsList(context.argsList()).ToList();
+                var parameters = ProcessArgsList(context.argsList());
                 return MakeExpression(ExpressionType.CreateArray, parameters.ToArray());
             }
 
@@ -276,15 +276,30 @@ public override Expression VisitStringInterpolationAtom([NotNull] ExpressionAntl
             private Expression MakeExpression(string functionType, params Expression[] children)
                 => Expression.MakeExpression(_lookupFunction(functionType) ?? throw new SyntaxErrorException($"{functionType} does not have an evaluator, it's not a built-in function or a custom function."), children);
 
-            private IEnumerable<Expression> ProcessArgsList(ExpressionAntlrParser.ArgsListContext context)
+            private IList<Expression> ProcessArgsList(ExpressionAntlrParser.ArgsListContext context)
             {
-                if (context != null)
+                var result = new List<Expression>();
+                if (context == null)
                 {
-                    foreach (var expression in context.expression())
+                    return result;
+                }
+
+                foreach (var child in context.children)
+                {
+                    if (child is ExpressionAntlrParser.LambdaContext lambda)
                     {
-                        yield return Visit(expression);
+                        var evalParam = MakeExpression(ExpressionType.Accessor, Expression.ConstantExpression(lambda.IDENTIFIER().GetText()));
+                        var evalFun = Visit(lambda.expression());
+                        result.Add(evalParam);
+                        result.Add(evalFun);
+                    }
+                    else if (child is ExpressionAntlrParser.ExpressionContext expression)
+                    {
+                        result.Add(Visit(expression));
                     }
                 }
+
+                return result;
             }
 
             private string EvalEscape(string text)

diff --git a/tests/AdaptiveExpressions.Tests/ExpressionParserTests.cs b/tests/AdaptiveExpressions.Tests/ExpressionParserTests.cs
@@ -830,15 +830,20 @@ public class ExpressionParserTests
             Test("join(createArray('a', 'b'), ',', ' and ')", "a and b"),
             Test("join(createArray(\r\n'a',\r\n 'b'), ','\r\n,\r\n ' and ')", "a and b"),
             Test("join(foreach(dialog, item, item.key), ',')", "x,instance,options,title,subTitle"),
+            Test("join(foreach(dialog, item => item.key), ',')", "x,instance,options,title,subTitle"),
             Test("foreach(dialog, item, item.value)[1].xxx", "instance"),
+            Test("foreach(dialog, item=>item.value)[1].xxx", "instance"),
             Test("join(foreach(items, item, item), ',')", "zero,one,two"),
+            Test("join(foreach(items, item=>item), ',')", "zero,one,two"),
             Test("join(foreach(indicesAndValues(items), item, item.value), ',')", "zero,one,two"),
             Test("join(foreach(nestedItems, i, i.x + first(nestedItems).x), ',')", "2,3,4", new HashSet<string> { "nestedItems" }),
             Test("join(foreach(items, item, concat(item, string(count(items)))), ',')", "zero3,one3,two3", new HashSet<string> { "items" }),
             Test("join(select(items, item, item), ',')", "zero,one,two"),
+            Test("join(select(items, item=> item), ',')", "zero,one,two"),
             Test("join(select(nestedItems, i, i.x + first(nestedItems).x), ',')", "2,3,4", new HashSet<string> { "nestedItems" }),
             Test("join(select(items, item, concat(item, string(count(items)))), ',')", "zero3,one3,two3", new HashSet<string> { "items" }),
             Test("join(where(items, item, item == 'two'), ',')", "two"),
+            Test("join(where(items, item => item == 'two'), ',')", "two"),
             Test("string(where(dialog, item, item.value=='Dialog Title'))", "{\"title\":\"Dialog Title\"}"),
             Test("first(where(indicesAndValues(items), elt, elt.index > 1)).value", "two"),
             Test("first(where(indicesAndValues(bag), elt, elt.index == \"three\")).value", 3),
@@ -899,6 +904,7 @@ public class ExpressionParserTests
             Test("{text: 'hello'}.text", "hello"),
             Test("string(addProperty({'key1':'value1'}, 'key2','value2'))", "{\"key1\":\"value1\",\"key2\":\"value2\"}"),
             Test("foreach(items, x, addProperty({}, 'a', x))[0].a", "zero"),
+            Test("foreach(items, x => addProperty({}, 'a', x))[0].a", "zero"),
             Test("string(setProperty({'key1':'value1'}, 'key1','value2'))", "{\"key1\":\"value2\"}"),
             Test("string(setProperty({}, 'key1','value2'))", "{\"key1\":\"value2\"}"),
             Test("string([{a: 1}, {b: 2}, {c: 3}][0])", "{\"a\":1}"),