add indexability in expressions (#3682)

allows us to change lines like this ```c# new IndexerExpression(output, i).Assign(Literal('-')).Terminate() ``` into lines like this ```c# output[i].Assign(Literal('-')).Terminate() ```
microsoft · Jun 27, 2024 · 7e68cdc · 7e68cdc
1 parent 8f837b1
commit 7e68cdc
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Showing 15 changed files with 67 additions and 63 deletions.
diff --git a/...p-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/ClientModelPlugin.cs b/...p-client-csharp/generator/Microsoft.Generator.CSharp.ClientModel/src/ClientModelPlugin.cs
@@ -7,10 +7,8 @@
 using System.ComponentModel.Composition;
 using Microsoft.CodeAnalysis;
 using Microsoft.Generator.CSharp.ClientModel.Providers;
-using Microsoft.Generator.CSharp.ClientModel.Snippets;
 using Microsoft.Generator.CSharp.Input;
 using Microsoft.Generator.CSharp.Providers;
-using Microsoft.Generator.CSharp.Snippets;
 
 namespace Microsoft.Generator.CSharp.ClientModel
 {

diff --git a/...rosoft.Generator.CSharp.ClientModel/src/Providers/ModelSerializationExtensionsProvider.cs b/...rosoft.Generator.CSharp.ClientModel/src/Providers/ModelSerializationExtensionsProvider.cs
@@ -13,7 +13,6 @@
 using Microsoft.Generator.CSharp.Providers;
 using Microsoft.Generator.CSharp.Snippets;
 using Microsoft.Generator.CSharp.Statements;
-using Microsoft.Generator.CSharp.TypedSnippets;
 using static Microsoft.Generator.CSharp.Snippets.Snippet;
 using static Microsoft.Generator.CSharp.ClientModel.Snippets.TypeFormattersSnippet;
 using static Microsoft.Generator.CSharp.ClientModel.Snippets.ModelSerializationExtensionsSnippet;
@@ -270,7 +269,7 @@ private MethodProvider BuildGetCharMethodProvider()
                     {
                         Throw(New.NotSupportedException(new FormattableStringExpression("Cannot convert \\\"{0}\\\" to a char", [text])))
                     },
-                    Return(text.Index(0))
+                    Return(text[0])
                 },
                 Throw(New.NotSupportedException(new FormattableStringExpression("Cannot convert {0} to a char", [element.ValueKind])))
                 );

diff --git a/.../generator/Microsoft.Generator.CSharp.ClientModel/src/Providers/TypeFormattersProvider.cs b/.../generator/Microsoft.Generator.CSharp.ClientModel/src/Providers/TypeFormattersProvider.cs
@@ -165,23 +165,24 @@ private MethodProvider BuildToBase64UrlStringMethodProvider()
                 Declare("numWholeOrPartialInputBlocks", new IntSnippet(new BinaryOperatorExpression("/", new KeywordExpression("checked", new BinaryOperatorExpression("+", valueLength, Int(2))), Int(3))), out var numWholeOrPartialInputBlocks),
                 Declare("size", new IntSnippet(new KeywordExpression("checked", new BinaryOperatorExpression("*", numWholeOrPartialInputBlocks, Int(4)))), out var size),
             };
-            var output = new VariableExpression(typeof(char[]), "output");
+            var outputVar = new VariableExpression(typeof(char[]), "output");
+            var output = new IndexableExpression(outputVar);
             body.Add(new MethodBodyStatement[]
             {
-                Declare(output, New.Array(typeof(char), size)),
+                Declare(outputVar, New.Array(typeof(char), size)),
                 EmptyLineStatement,
                 Declare("numBase64Chars", new IntSnippet(new InvokeStaticMethodExpression(typeof(Convert), nameof(Convert.ToBase64CharArray), [value, Int(0), valueLength, output, Int(0)])), out var numBase64Chars),
                 EmptyLineStatement,
                 Declare("i", Int(0), out var i),
                 new ForStatement(null, LessThan(i, numBase64Chars), new UnaryOperatorExpression("++", i, true))
                 {
-                    Declare("ch", new CharSnippet(new IndexerExpression(output, i)), out var ch),
+                    Declare("ch", new CharSnippet(output[i]), out var ch),
                     new IfElseStatement(new IfStatement(Equal(ch, Literal('+')))
                     {
-                        new IndexerExpression(output, i).Assign(Literal('-')).Terminate()
+                        output[i].Assign(Literal('-')).Terminate()
                     }, new IfElseStatement(new IfStatement(Equal(ch, Literal('/')))
                     {
-                        new IndexerExpression(output, i).Assign(Literal('_')).Terminate()
+                        output[i].Assign(Literal('_')).Terminate()
                     }, new IfStatement(Equal(ch, Literal('=')))
                     {
                         Break
@@ -215,27 +216,28 @@ private MethodProvider BuildFromBase64UrlString()
                     SwitchCaseExpression.Default(ThrowExpression(New.InvalidOperationException(Literal("Malformed input"))))
                 })), out var paddingCharsToAdd)
             };
-            var output = new VariableExpression(typeof(char[]), "output");
+            var outputVar = new VariableExpression(typeof(char[]), "output");
+            var output = new IndexableExpression(outputVar);
             var outputLength = output.Property("Length");
             body.Add(new MethodBodyStatement[]
             {
-                Declare(output, New.Array(typeof(char), new BinaryOperatorExpression("+", value.Length, paddingCharsToAdd))),
+                Declare(outputVar, New.Array(typeof(char), new BinaryOperatorExpression("+", value.Length, paddingCharsToAdd))),
                 Declare("i", Int(0), out var i),
                 new ForStatement(null, LessThan(i, value.Length), new UnaryOperatorExpression("++", i, true))
                 {
-                    Declare("ch", value.Index(i), out var ch),
+                    Declare("ch", value[i], out var ch),
                     new IfElseStatement(new IfStatement(Equal(ch, Literal('-')))
                     {
-                        new IndexerExpression(output, i).Assign(Literal('+')).Terminate()
+                        output[i].Assign(Literal('+')).Terminate()
                     }, new IfElseStatement(new IfStatement(Equal(ch, Literal('_')))
                     {
-                        new IndexerExpression(output, i).Assign(Literal('/')).Terminate()
-                    }, new IndexerExpression(output, i).Assign(ch).Terminate()))
+                        output[i].Assign(Literal('/')).Terminate()
+                    }, output[i].Assign(ch).Terminate()))
                 },
                 EmptyLineStatement,
                 new ForStatement(null, LessThan(i, outputLength), new UnaryOperatorExpression("++", i, true))
                 {
-                    new IndexerExpression(output, i).Assign(Literal('=')).Terminate()
+                    output[i].Assign(Literal('=')).Terminate()
                 },
                 EmptyLineStatement,
                 Return(new InvokeStaticMethodExpression(typeof(Convert), nameof(Convert.FromBase64CharArray), new[] { output, Int(0), outputLength }))

diff --git a/...ent-csharp/generator/Microsoft.Generator.CSharp/src/Expressions/ArrayElementExpression.cs b/...ent-csharp/generator/Microsoft.Generator.CSharp/src/Expressions/ArrayElementExpression.cs
diff --git a/...client-csharp/generator/Microsoft.Generator.CSharp/src/Expressions/IndexableExpression.cs b/...client-csharp/generator/Microsoft.Generator.CSharp/src/Expressions/IndexableExpression.cs
@@ -0,0 +1,21 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using Microsoft.Generator.CSharp.Expressions;
+
+namespace Microsoft.Generator.CSharp.Snippets
+{
+    public record IndexableExpression(ValueExpression Inner) : ValueExpression
+    {
+        public IndexableExpression(CSharpType type, string name) : this(new VariableExpression(type, name))
+        {
+        }
+
+        public ValueExpression this[ValueExpression index] => new IndexerExpression(this, index);
+
+        internal override void Write(CodeWriter writer)
+        {
+            Inner.Write(writer);
+        }
+    }
+}
diff --git a/...rp/generator/Microsoft.Generator.CSharp/src/Providers/ChangeTrackingDictionaryProvider.cs b/...rp/generator/Microsoft.Generator.CSharp/src/Providers/ChangeTrackingDictionaryProvider.cs
@@ -28,7 +28,7 @@ private class ChangeTrackingDictionaryTemplate<TKey, TValue> { }
         private readonly DictionarySnippet _innerDictionary;
         private readonly MethodSignature _ensureDictionarySignature;
 
-        private InvokeInstanceMethodExpression EnsureDictionary { get; init; }
+        private IndexableExpression EnsureDictionary { get; init; }
         private BoolSnippet IsUndefined { get; } = new BoolSnippet(new MemberExpression(This, "IsUndefined"));
 
         public ChangeTrackingDictionaryProvider()
@@ -43,7 +43,7 @@ public ChangeTrackingDictionaryProvider()
             _innerDictionaryField = new FieldProvider(FieldModifiers.Private, new CSharpType(typeof(IDictionary<,>), _tKey, _tValue), "_innerDictionary");
             _innerDictionary = new DictionarySnippet(_tKey, _tValue, new VariableExpression(_IDictionary, _innerDictionaryField.Declaration));
             _ensureDictionarySignature = new MethodSignature("EnsureDictionary", null, MethodSignatureModifiers.Public, _IDictionary, null, Array.Empty<ParameterProvider>());
-            EnsureDictionary = This.Invoke(_ensureDictionarySignature);
+            EnsureDictionary = new(This.Invoke(_ensureDictionarySignature));
         }
 
         protected override TypeSignatureModifiers GetDeclarationModifiers()
@@ -160,11 +160,11 @@ private PropertyProvider BuildIndexer()
                     {
                         Throw(New.Instance(typeof(KeyNotFoundException), Nameof(_indexParam)))
                     },
-                    Return(new ArrayElementExpression(EnsureDictionary, _indexParam)),
+                    Return(EnsureDictionary[_indexParam]),
                 },
                 new MethodBodyStatement[]
                 {
-                    new ArrayElementExpression(EnsureDictionary, _indexParam).Assign(new KeywordExpression("value", null)).Terminate()
+                    EnsureDictionary[_indexParam].Assign(Value).Terminate()
                 }));
         }
 

diff --git a/...t-csharp/generator/Microsoft.Generator.CSharp/src/Providers/ChangeTrackingListProvider.cs b/...t-csharp/generator/Microsoft.Generator.CSharp/src/Providers/ChangeTrackingListProvider.cs
@@ -28,7 +28,7 @@ private class ChangeTrackingListTemplate<T> { }
         private readonly CSharpType _iReadOnlyListOfT;
 
         private BoolSnippet IsUndefined { get; } = new BoolSnippet(new MemberExpression(This, "IsUndefined"));
-        private InvokeInstanceMethodExpression EnsureList { get; init; }
+        private IndexableExpression EnsureList { get; init; }
 
         public ChangeTrackingListProvider()
         {
@@ -42,7 +42,7 @@ public ChangeTrackingListProvider()
             _innerList = new VariableExpression(_iListOfT, _innerListField.Declaration);
             _tArray = typeof(ChangeTrackingListTemplate<>).GetGenericArguments()[0].MakeArrayType();
             _tParam = new ParameterProvider("item", $"The item.", _t);
-            EnsureList = This.Invoke(_ensureListSignature);
+            EnsureList = new(This.Invoke(_ensureListSignature));
         }
 
         protected override TypeSignatureModifiers GetDeclarationModifiers()
@@ -136,15 +136,15 @@ private PropertyProvider BuildIndexer()
                     {
                         Throw(New.Instance(typeof(ArgumentOutOfRangeException), Nameof(_indexParam)))
                     },
-                    Return(new ArrayElementExpression(EnsureList, _indexParam)),
+                    Return(EnsureList[_indexParam]),
                 },
                 new MethodBodyStatement[]
                 {
                     new IfStatement(IsUndefined)
                     {
                         Throw(New.Instance(typeof(ArgumentOutOfRangeException), Nameof(_indexParam)))
                     },
-                    new ArrayElementExpression(EnsureList, _indexParam).Assign(new KeywordExpression("value", null)).Terminate()
+                    EnsureList[_indexParam].Assign(Value).Terminate()
                 }));
         }
 

diff --git a/packages/http-client-csharp/generator/Microsoft.Generator.CSharp/src/Snippets/Snippet.New.cs b/packages/http-client-csharp/generator/Microsoft.Generator.CSharp/src/Snippets/Snippet.New.cs
@@ -41,10 +41,10 @@ public static ValueExpression ArgumentException(ValueExpression parameter, Value
             public static ValueExpression JsonException(ValueExpression message)
                 => Instance(typeof(JsonException), message);
 
-            public static EnumerableSnippet Array(CSharpType? elementType) => new(elementType ?? typeof(object), new NewArrayExpression(elementType));
-            public static EnumerableSnippet Array(CSharpType? elementType, params ValueExpression[] items) => new(elementType ?? typeof(object), new NewArrayExpression(elementType, new ArrayInitializerExpression(items)));
-            public static EnumerableSnippet Array(CSharpType? elementType, bool isInline, params ValueExpression[] items) => new(elementType ?? typeof(object), new NewArrayExpression(elementType, new ArrayInitializerExpression(items, isInline)));
-            public static EnumerableSnippet Array(CSharpType? elementType, ValueExpression size) => new(elementType ?? typeof(object), new NewArrayExpression(elementType, Size: size));
+            public static IndexableExpression Array(CSharpType? elementType) => new(new NewArrayExpression(elementType));
+            public static IndexableExpression Array(CSharpType? elementType, params ValueExpression[] items) => new(new NewArrayExpression(elementType, new ArrayInitializerExpression(items)));
+            public static IndexableExpression Array(CSharpType? elementType, bool isInline, params ValueExpression[] items) => new(new NewArrayExpression(elementType, new ArrayInitializerExpression(items, isInline)));
+            public static IndexableExpression Array(CSharpType? elementType, ValueExpression size) => new(new NewArrayExpression(elementType, Size: size));
 
             public static DictionarySnippet Dictionary(CSharpType keyType, CSharpType valueType)
                 => new(keyType, valueType, new NewInstanceExpression(new CSharpType(typeof(Dictionary<,>), keyType, valueType), []));

diff --git a/packages/http-client-csharp/generator/Microsoft.Generator.CSharp/src/Snippets/Snippet.cs b/packages/http-client-csharp/generator/Microsoft.Generator.CSharp/src/Snippets/Snippet.cs
@@ -30,6 +30,7 @@ internal override void Write(CodeWriter writer)
 
         public static ValueExpression DefaultOf(CSharpType type) => type is { IsValueType: true, IsNullable: false } ? Default.CastTo(type) : Null.CastTo(type);
 
+        public static ValueExpression Value { get; } = new KeywordExpression("value", null);
         public static ValueExpression Default { get; } = new KeywordExpression("default", null);
         public static ValueExpression Null { get; } = new KeywordExpression("null", null);
         public static ValueExpression This { get; } = new KeywordExpression("this", null);

diff --git a/...client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/DictionarySnippet.cs b/...client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/DictionarySnippet.cs
@@ -14,5 +14,7 @@ public MethodBodyStatement Add(ValueExpression key, ValueExpression value)
 
         public MethodBodyStatement Add(KeyValuePairSnippet pair)
             => Untyped.Invoke(nameof(Dictionary<object, object>.Add), pair).Terminate();
+
+        public ValueExpression this[ValueExpression key] => new IndexerExpression(Untyped, key);
     }
 }
diff --git a/.../http-client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/ListSnippet.cs b/.../http-client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/ListSnippet.cs
@@ -11,6 +11,8 @@ public sealed record ListSnippet(CSharpType ItemType, ValueExpression Untyped) :
     {
         public MethodBodyStatement Add(ValueExpression item) => Untyped.Invoke(nameof(List<object>.Add), item).Terminate();
 
-        public ValueExpression ToArray() => Untyped.Invoke(nameof(List<object>.ToArray));
+        public IndexableExpression ToArray() => new(Untyped.Invoke(nameof(List<object>.ToArray)));
+
+        public ValueExpression this[ValueExpression index] => new IndexerExpression(Untyped, index);
     }
 }
diff --git a/...ttp-client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/ObjectSnippet.cs b/...ttp-client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/ObjectSnippet.cs
@@ -2,9 +2,8 @@
 // Licensed under the MIT License.
 
 using Microsoft.Generator.CSharp.Expressions;
-using Microsoft.Generator.CSharp.Snippets;
 
-namespace Microsoft.Generator.CSharp.TypedSnippets
+namespace Microsoft.Generator.CSharp.Snippets
 {
     public sealed record ObjectSnippet(ValueExpression Untyped) : TypedSnippet<object>(Untyped)
     {

diff --git a/...ttp-client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/StringSnippet.cs b/...ttp-client-csharp/generator/Microsoft.Generator.CSharp/src/TypedSnippets/StringSnippet.cs
@@ -9,8 +9,6 @@ namespace Microsoft.Generator.CSharp.Snippets
 {
     public sealed record StringSnippet(ValueExpression Untyped) : TypedSnippet<string>(Untyped)
     {
-        public CharSnippet Index(ValueExpression index) => new(new IndexerExpression(this, index));
-        public CharSnippet Index(int index) => Index(Snippet.Literal(index));
         public ValueExpression Length => Property(nameof(string.Length));
 
         public static BoolSnippet Equals(StringSnippet left, StringSnippet right, StringComparison comparisonType)
@@ -29,5 +27,9 @@ public StringSnippet Substring(ValueExpression startIndex)
             => new(new InvokeInstanceMethodExpression(this, nameof(string.Substring), new[] { startIndex }, null, false));
         public ValueExpression ToCharArray()
             => new InvokeInstanceMethodExpression(this, nameof(string.ToCharArray), Array.Empty<ValueExpression>(), null, false);
+
+        public CharSnippet this[ValueExpression index] => new(new IndexerExpression(this, index));
+
+        public CharSnippet this[int index] => this[Snippet.Literal(index)];
     }
 }
diff --git a/...http-client-csharp/generator/Microsoft.Generator.CSharp/test/Mocks/MockCodeModelPlugin.cs b/...http-client-csharp/generator/Microsoft.Generator.CSharp/test/Mocks/MockCodeModelPlugin.cs
@@ -5,7 +5,6 @@
 using System.Collections.Generic;
 using Microsoft.Generator.CSharp.Input;
 using Microsoft.Generator.CSharp.Providers;
-using Microsoft.Generator.CSharp.Snippets;
 
 namespace Microsoft.Generator.CSharp.Tests
 {