Update to Serilog 4, tidy up

serilog-expressions.sln.DotSettings

@@ -1,4 +1,5 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=CI/@EntryIndexedValue">CI</s:String>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Acerola/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Comparand/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=delim/@EntryIndexedValue">True</s:Boolean>

src/Serilog.Expressions/Expressions/Ast/AccessorExpression.cs

@@ -14,6 +14,14 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An accessor retrieves a property from a (structured) object. For example, in the expression
+/// <code>Headers.ContentType</code> the <code>.</code> operator forms an accessor expression that
+/// retrieves the <code>ContentType</code> property from the <code>Headers</code> object.
+/// </summary>
+/// <remarks>Note that the AST type can represent accessors that cannot be validly written using
+/// <code>.</code> notation. In these cases, if the accessor is formatted back out as an expression,
+/// <see cref="IndexerExpression"/> notation will be used.</remarks>
 class AccessorExpression : Expression
 {
     public AccessorExpression(Expression receiver, string memberName)

src/Serilog.Expressions/Expressions/Ast/AmbientNameExpression.cs

@@ -14,6 +14,11 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An ambient name is generally a property name or built-in that appears standalone in an expression. For example,
+/// in <code>Headers.ContentType</code>, <code>Headers</code> is an ambient name that produces an
+/// <see cref="AmbientNameExpression"/>. Built-ins like <code>@Level</code> are also parsed as ambient names.
+/// </summary>
 class AmbientNameExpression : Expression
 {
     readonly bool _requiresEscape;

src/Serilog.Expressions/Expressions/Ast/ArrayExpression.cs

@@ -14,6 +14,13 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An array expression constructs an array from a list of elements. For example, <code>[1, 2, 3]</code> is an
+/// array expression. The items in an array expression can be literal values or expressions, like in the
+/// above example, or they can be spread expressions that describe zero or more elements to include in the
+/// list. Whether included via regular elements or spread expressions, undefined values are ignored and won't
+/// appear in the resulting array value.
+/// </summary>
 class ArrayExpression : Expression
 {
     public ArrayExpression(Element[] elements)

src/Serilog.Expressions/Expressions/Ast/CallExpression.cs

@@ -14,6 +14,10 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// A <see cref="CallExpression"/> is a function call made up of the function name, parenthesised argument
+/// list, and optional postfix <code>ci</code> modifier. For example, <code>Substring(RequestPath, 0, 5)</code>.
+/// </summary>
 class CallExpression : Expression
 {
     public CallExpression(bool ignoreCase, string operatorName, params Expression[] operands)

src/Serilog.Expressions/Expressions/Ast/ConstantExpression.cs

@@ -17,6 +17,9 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// A constant such as <code>'hello'</code>, <code>true</code>, <code>null</code>, or <code>123.45</code>.
+/// </summary>
 class ConstantExpression : Expression
 {
     public ConstantExpression(LogEventPropertyValue constant)
@@ -30,19 +33,14 @@ public override string ToString()
     {
         if (Constant is ScalarValue sv)
         {
-            switch (sv.Value)
+            return sv.Value switch
             {
-                case string s:
-                    return "'" + s.Replace("'", "''") + "'";
-                case true:
-                    return "true";
-                case false:
-                    return "false";
-                case IFormattable formattable:
-                    return formattable.ToString(null, CultureInfo.InvariantCulture);
-                default:
-                    return (sv.Value ?? "null").ToString() ?? "<ToString() returned null>";
-            }
+                string s => "'" + s.Replace("'", "''") + "'",
+                true => "true",
+                false => "false",
+                IFormattable formattable => formattable.ToString(null, CultureInfo.InvariantCulture),
+                _ => (sv.Value ?? "null").ToString() ?? "<ToString() returned null>"
+            };
         }
 
         return Constant.ToString();

src/Serilog.Expressions/Expressions/Ast/Element.cs

@@ -14,6 +14,7 @@
 
 namespace Serilog.Expressions.Ast;
 
-abstract class Element
-{
-}
+/// <summary>
+/// An element in an <see cref="ArrayExpression"/>.
+/// </summary>
+abstract class Element;

src/Serilog.Expressions/Expressions/Ast/Expression.cs

@@ -14,8 +14,15 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An AST node.
+/// </summary>
 abstract class Expression
 {
-    // Used only as an enabler for testing and debugging.
+    /// <summary>
+    /// The <see cref="ToString"/> representation of an <see cref="Expression"/> is <strong>not</strong>
+    /// guaranteed to be syntactically valid: this is provided for debugging purposes only.
+    /// </summary>
+    /// <returns>A textual representation of the expression.</returns>
     public abstract override string ToString();
 }

src/Serilog.Expressions/Expressions/Ast/IndexOfMatchExpression.cs

@@ -16,6 +16,10 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// A non-syntax expression tree node used when compiling the <see cref="Operators.OpIndexOfMatch"/>,
+/// <see cref="Operators.OpIsMatch"/>, and SQL-style <code>like</code> expressions.
+/// </summary>
 class IndexOfMatchExpression : Expression
 {
     public Expression Corpus { get; }

src/Serilog.Expressions/Expressions/Ast/IndexerExpression.cs

@@ -14,6 +14,11 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An <see cref="IndexerExpression"/> retrieves a property from an object, by name, or an item from an array
+/// by zero-based numeric index. For example, <code>Headers['Content-Type']</code> and <code>Items[2]</code> are
+/// parsed as indexer expressions.
+/// </summary>
 class IndexerExpression : Expression
 {
     public Expression Receiver { get; }

src/Serilog.Expressions/Expressions/Ast/IndexerWildcard.cs

@@ -14,4 +14,7 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// Describes the wildcard in a <see cref="IndexerWildcardExpression"/>.
+/// </summary>
 enum IndexerWildcard { Undefined, Any, All }

src/Serilog.Expressions/Expressions/Ast/IndexerWildcardExpression.cs

@@ -14,6 +14,11 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An indexer wildcard is a placeholder in a property path expression. For example,
+/// in <code>Headers[?] = 'test'</code>, the question-mark token is a wildcard that means "any property of
+/// the <code>Headers</code> object". The other wildcard indexer is the asterisk, meaning "all".
+/// </summary>
 class IndexerWildcardExpression : Expression
 {
     public IndexerWildcardExpression(IndexerWildcard wildcard)

src/Serilog.Expressions/Expressions/Ast/ItemElement.cs

@@ -14,6 +14,9 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// A single item in an <see cref="ArrayExpression"/>.
+/// </summary>
 class ItemElement : Element
 {
     public Expression Value { get; }

src/Serilog.Expressions/Expressions/Ast/LambdaExpression.cs

@@ -14,6 +14,10 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// A non-syntax expression tree node used in the compilation of <see cref="IndexerWildcardExpression"/>. Only
+/// very limited support for lambda expressions is currently present.
+/// </summary>
 class LambdaExpression : Expression
 {
     public LambdaExpression(ParameterExpression[] parameters, Expression body)

src/Serilog.Expressions/Expressions/Ast/LocalNameExpression.cs

@@ -14,6 +14,9 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// Represents the iteration variable in template <code>#each</code> directives.
+/// </summary>
 class LocalNameExpression : Expression
 {
     public LocalNameExpression(string name)

src/Serilog.Expressions/Expressions/Ast/Member.cs

@@ -14,6 +14,7 @@
 
 namespace Serilog.Expressions.Ast;
 
-abstract class Member
-{
-}
+/// <summary>
+/// A member in an <see cref="ObjectExpression"/>.
+/// </summary>
+abstract class Member;

src/Serilog.Expressions/Expressions/Ast/ObjectExpression.cs

@@ -14,6 +14,11 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// Constructs an object given a list of members. Members can be <code>name: value</code> pairs, or spread
+/// expressions that include members from another object. Where names conflict, the rightmost appearance of
+/// a name wins. Members that evaluate to an undefined value do not appear in the resulting object.
+/// </summary>
 class ObjectExpression : Expression
 {
     public ObjectExpression(Member[] members)

src/Serilog.Expressions/Expressions/Ast/ParameterExpression.cs

@@ -14,6 +14,9 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// Non-syntax expression type used to represent parameters in <see cref="LambdaExpression"/> bodies.
+/// </summary>
 class ParameterExpression : Expression
 {
     public ParameterExpression(string parameterName)

src/Serilog.Expressions/Expressions/Ast/PropertyMember.cs

@@ -16,6 +16,11 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An <see cref="ObjectExpression"/> member comprising an optionally-quoted name and a value, for example
+/// the object <code>{Username: 'alice'}</code> includes a single <see cref="PropertyMember"/> with name
+/// <code>Username</code> and value <code>'alice'</code>.
+/// </summary>
 class PropertyMember : Member
 {
     public string Name { get; }

src/Serilog.Expressions/Expressions/Ast/SpreadElement.cs

@@ -14,6 +14,13 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An element in an <see cref="ArrayExpression"/> that describes zero or more items to include in the array.
+/// Spread elements are written with two dots preceding an expression that evaluates to an array of elements to
+/// insert into the result array at the position of the spread element, for example, in <code>[1, 2, ..Others]</code>,
+/// the <code>..Others</code> expression is a spread element. If the value of the array in the spread is
+/// undefined, no items will be added to the list.
+/// </summary>
 class SpreadElement : Element
 {
     public Expression Content { get; }

src/Serilog.Expressions/Expressions/Ast/SpreadMember.cs

@@ -14,6 +14,11 @@
 
 namespace Serilog.Expressions.Ast;
 
+/// <summary>
+/// An <see cref="ObjectExpression"/> member that designates another object from which to copy members into the
+/// current object. Spread member expressions comprise two dots preceding an expression that is expected to
+/// evaluate to an object.
+/// </summary>
 class SpreadMember : Member
 {
     public Expression Content { get; }

src/Serilog.Expressions/Expressions/Compilation/DefaultFunctionNameResolver.cs

@@ -22,7 +22,7 @@ public static NameResolver Build(NameResolver? additionalNameResolver)
     {
         var defaultResolver = new StaticMemberNameResolver(typeof(RuntimeOperators));
         return additionalNameResolver == null
-            ? (NameResolver) defaultResolver
+            ? defaultResolver
             : new OrderedNameResolver(new[] {defaultResolver, additionalNameResolver });
     }
 }

src/Serilog.Expressions/Expressions/Compilation/Linq/LinqExpressionCompiler.cs

@@ -176,7 +176,7 @@ static ExpressionBody CompileLogical(Func<ExpressionBody, ExpressionBody, Expres
     {
         return LX.Convert(
             LX.New(
-                typeof(ScalarValue).GetConstructor(new[]{typeof(object)})!,
+                typeof(ScalarValue).GetConstructor([typeof(object)])!,
                 LX.Convert(apply(
                     LX.Call(CoerceToScalarBooleanMethod, lhs),
                     LX.Call(CoerceToScalarBooleanMethod, rhs)), typeof(object))),
@@ -253,7 +253,7 @@ protected override ExpressionBody Transform(Ast.LambdaExpression lmx)
         var lambda = LX.Lambda(delegateType, rewritten!, parameters.Select(px => px.Item2).ToArray());
 
         // Unfortunately, right now, functions need to be threaded through in constant scalar values :-D
-        return LX.New(typeof(ScalarValue).GetConstructor(new[] {typeof(object)})!,
+        return LX.New(typeof(ScalarValue).GetConstructor([typeof(object)])!,
             LX.Convert(lambda, typeof(object)));
     }
 

src/Serilog.Expressions/Expressions/Compilation/Linq/ParameterReplacementVisitor.cs

@@ -23,7 +23,7 @@ class ParameterReplacementVisitor : ExpressionVisitor
     public static Expression ReplaceParameters(LambdaExpression lambda, params ParameterExpression[] newParameters)
     {
         var v = new ParameterReplacementVisitor(lambda.Parameters.ToArray(), newParameters);
-        return v.Visit(lambda.Body);
+        return v.Visit(lambda.Body)!;
     }
 
     ParameterReplacementVisitor(ParameterExpression[] from, ParameterExpression[] to)

src/Serilog.Expressions/Expressions/Compilation/Text/LikeSyntaxTransformer.cs

@@ -48,9 +48,7 @@ protected override Expression Transform(CallExpression call)
 
     Expression TryCompileLikeExpression(bool ignoreCase, Expression corpus, Expression like)
     {
-        if (like is ConstantExpression cx &&
-            cx.Constant is ScalarValue scalar &&
-            scalar.Value is string s)
+        if (like is ConstantExpression { Constant: ScalarValue { Value: string s } })
         {
             var regex = LikeToRegex(s);
             var opts = RegexOptions.Compiled | RegexOptions.ExplicitCapture;

src/Serilog.Expressions/Expressions/Compilation/Text/TextMatchingTransformer.cs

@@ -49,9 +49,7 @@ protected override Expression Transform(CallExpression call)
 
     Expression TryCompileIndexOfMatch(bool ignoreCase, Expression corpus, Expression regex)
     {
-        if (regex is ConstantExpression cx &&
-            cx.Constant is ScalarValue scalar &&
-            scalar.Value is string s)
+        if (regex is ConstantExpression { Constant: ScalarValue { Value: string s } })
         {
             var opts = RegexOptions.Compiled | RegexOptions.ExplicitCapture;
             if (ignoreCase)

src/Serilog.Expressions/Expressions/Compilation/Wildcards/WildcardComprehensionTransformer.cs

@@ -68,7 +68,7 @@ protected override Expression Transform(CallExpression lx)
         comparisonArgs[indexerOperand] = nestedComparand;
         var body = new CallExpression(lx.IgnoreCase, lx.OperatorName, comparisonArgs);
 
-        var lambda = new LambdaExpression(new[] { px }, body);
+        var lambda = new LambdaExpression([px], body);
 
         var op = Operators.ToRuntimeWildcardOperator(wc);
         var call = new CallExpression(false, op, coll, lambda);
@@ -84,7 +84,7 @@ protected override Expression Transform(IndexerExpression ix)
 
         var px = new ParameterExpression("p" + _nextParameter++);
         var coll = Transform(ix.Receiver);
-        var lambda = new LambdaExpression(new[] { px }, px);
+        var lambda = new LambdaExpression([px], px);
         var op = Operators.ToRuntimeWildcardOperator(wx.Wildcard);
         return new CallExpression(false, op, coll, lambda);
     }

src/Serilog.Expressions/Expressions/Helpers.cs

@@ -19,7 +19,7 @@ namespace Serilog.Expressions
     /// <summary>
     /// Helper methods.
     /// </summary>
-    internal static class Helpers
+    static class Helpers
     {
         /// <summary>
         /// Backport .NET Standard 2.1 additions to maintain .NET Standard 2.0 compatibility.
@@ -35,7 +35,7 @@ internal static class Helpers
         /// <returns></returns>
         public static bool Contains(this string source, string value, StringComparison comparisonType)
         {
-            return source?.IndexOf(value, comparisonType) >= 0;
+            return source.IndexOf(value, comparisonType) >= 0;
         }
     }
 }

src/Serilog.Expressions/Expressions/Parsing/ExpressionTextParsers.cs

@@ -29,7 +29,7 @@ static class ExpressionTextParsers
 
     public static readonly TextParser<string> HexInteger =
         Span.EqualTo("0x")
-            .IgnoreThen(Character.Digit.Or(Character.Matching(ch => ch >= 'a' && ch <= 'f' || ch >= 'A' && ch <= 'F', "a-f"))
+            .IgnoreThen(Character.Digit.Or(Character.Matching(ch => ch is >= 'a' and <= 'f' or >= 'A' and <= 'F', "a-f"))
                 .Named("hex digit")
                 .AtLeastOnce())
             .Select(chars => new string(chars));