3.2.0 Release

Directory.Build.props

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project>
+  <PropertyGroup>
+    <Nullable>enable</Nullable>
+    <LangVersion>latest</LangVersion>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <AssemblyOriginatorKeyFile>../../assets/Serilog.snk</AssemblyOriginatorKeyFile>
+    <SignAssembly>true</SignAssembly>
+    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
+  </PropertyGroup>
+</Project>

README.md

@@ -147,7 +147,7 @@ The built-in properties mirror those available in the CLEF format.
 | Array | An array of values, in square brackets | `[1, 'two', null]` |
 | Object | A mapping of string keys to values; keys that are valid identifiers do not need to be quoted | `{a: 1, 'b c': 2, d}` |
 
-Array and object literals support the spread operator: `[1, 2, ..rest]`, `{a: 1, ..other}`. Specifying an undefined
+Array and object literals support the spread operator: `[1, 2, ..others]`, `{a: 1, ..others}`. Specifying an undefined
 property in an object literal will remove it from the result: `{..User, Email: Undefined()}`
 
 ### Operators and conditionals
@@ -184,7 +184,8 @@ calling a function will be undefined if:
 
 | Function | Description |
 | :--- | :--- |
-| `Coalesce(p0, p1, ..pN)` | Returns the first defined, non-null argument. |
+| `Coalesce(p0, p1, [..pN])` | Returns the first defined, non-null argument. |
+| `Concat(s0, s1, [..sN])` | Concatenate two or more strings. |
 | `Contains(s, t)` | Tests whether the string `s` contains the substring `t`. |
 | `ElementAt(x, i)` | Retrieves a property of `x` by name `i`, or array element of `x` by numeric index `i`. |
 | `EndsWith(s, t)` | Tests whether the string `s` ends with substring `t`. |
@@ -195,7 +196,7 @@ calling a function will be undefined if:
 | `LastIndexOf(s, t)` | Returns the last index of substring `t` in string `s`, or -1 if the substring does not appear. |
 | `Length(x)` | Returns the length of a string or array. |
 | `Now()` | Returns `DateTimeOffset.Now`. |
-| `Rest()` | In an `ExpressionTemplate`, returns an object containing the first-class event properties not otherwise referenced in the template or the event's message. |
+| `Rest([deep])` | In an `ExpressionTemplate`, returns an object containing the first-class event properties not otherwise referenced in the template. If `deep` is `true`, also excludes properties referenced in the event's message template. |
 | `Round(n, m)` | Round the number `n` to `m` decimal places. |
 | `StartsWith(s, t)` | Tests whether the string `s` starts with substring `t`. |
 | `Substring(s, start, [length])` | Return the substring of string `s` from `start` to the end of the string, or of `length` characters, if this argument is supplied. |
@@ -352,7 +353,7 @@ convert the result to plain-old-.NET-types like `string`, `bool`, `Dictionary<K,
 User-defined functions can be plugged in by implementing static methods that:
 
  * Return `LogEventPropertyValue?`,
- * Have arguments of type `LogEventPropertyValue?`,
+ * Have arguments of type `LogEventPropertyValue?` or `LogEvent`,
  * If the `ci` modifier is supported, accept a `StringComparison`, and
  * If culture-specific formatting or comparisons are used, accepts an `IFormatProvider`.
 

serilog-expressions.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.26430.15
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.31410.223
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{91E482DE-E1E7-4CE1-9511-C0AF07F3648A}"
 EndProject
@@ -11,6 +11,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "global", "global", "{24B112
 		.gitignore = .gitignore
 		appveyor.yml = appveyor.yml
 		Build.ps1 = Build.ps1
+		Directory.Build.props = Directory.Build.props
 		LICENSE = LICENSE
 		README.md = README.md
 		RunPerfTests.ps1 = RunPerfTests.ps1
@@ -60,4 +61,7 @@ Global
 		{3C2D8E01-5580-426A-BDD9-EC59CD98E618} = {B03B3086-D197-4B32-9AE2-8536C345EA2D}
 		{D7A37F73-BBA3-4DAE-9648-1A753A86F968} = {B03B3086-D197-4B32-9AE2-8536C345EA2D}
 	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {EB6672D6-318E-493E-8B60-77F5A7A90E66}
+	EndGlobalSection
 EndGlobal

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

@@ -20,7 +20,6 @@
 using System.Text.RegularExpressions;
 using Serilog.Events;
 using Serilog.Expressions.Runtime;
-using Serilog.Formatting.Display;
 using Serilog.Parsing;
 using Serilog.Templates.Compilation;
 
@@ -32,7 +31,7 @@ static class Intrinsics
     {
         static readonly LogEventPropertyValue NegativeOne = new ScalarValue(-1);
         static readonly LogEventPropertyValue Tombstone = new ScalarValue("😬 (if you see this you have found a bug.)");
-        
+
         public static List<LogEventPropertyValue?> CollectSequenceElements(LogEventPropertyValue?[] elements)
         {
             return elements.ToList();
@@ -53,18 +52,18 @@ static class Intrinsics
             if (content is SequenceValue sequence)
                 foreach (var element in sequence.Elements)
                     elements.Add(element);
-            
+
             return elements;
         }
 
         public static LogEventPropertyValue ConstructSequenceValue(List<LogEventPropertyValue?> elements)
         {
             if (elements.Any(el => el == null))
                 return new SequenceValue(elements.Where(el => el != null));
-            
+
             return new SequenceValue(elements);
         }
-        
+
         public static List<LogEventProperty> CollectStructureProperties(string[] names, LogEventPropertyValue?[] values)
         {
             var properties = new List<LogEventProperty>();
@@ -85,7 +84,7 @@ public static LogEventPropertyValue ConstructStructureValue(List<LogEventPropert
 
             return new StructureValue(properties);
         }
-        
+
         public static List<LogEventProperty> ExtendStructureValueWithSpread(
             List<LogEventProperty> properties,
             LogEventPropertyValue? content)
@@ -99,7 +98,7 @@ public static List<LogEventProperty> ExtendStructureValueWithSpread(
 
             return properties;
         }
-        
+
         public static List<LogEventProperty> ExtendStructureValueWithProperty(
             List<LogEventProperty> properties,
             string name,
@@ -129,7 +128,7 @@ public static bool CoerceToScalarBoolean(LogEventPropertyValue value)
                 return b;
             return false;
         }
-        
+
         public static LogEventPropertyValue? IndexOfMatch(LogEventPropertyValue value, Regex regex)
         {
             if (value is ScalarValue scalar &&
@@ -193,9 +192,9 @@ public static string RenderMessage(CompiledMessageToken formatter, EvaluationCon
                 if (token is PropertyToken {Format: { }} pt)
                 {
                     elements ??= new List<LogEventPropertyValue>();
-                    
+
                     var space = new StringWriter();
-                  
+
                     pt.Render(logEvent.Properties, space, formatProvider);
                     elements.Add(new ScalarValue(space.ToString()));
                 }

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

@@ -17,6 +17,8 @@
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
+using System.Runtime.InteropServices;
+using System.Text;
 using Serilog.Events;
 using Serilog.Expressions.Ast;
 using Serilog.Expressions.Compilation.Transformations;
@@ -27,6 +29,7 @@
 using ParameterExpression = System.Linq.Expressions.ParameterExpression;
 using LX = System.Linq.Expressions.Expression;
 using ExpressionBody = System.Linq.Expressions.Expression;
+// ReSharper disable UseIndexFromEndExpression
 
 namespace Serilog.Expressions.Compilation.Linq
 {
@@ -101,11 +104,18 @@ protected override ExpressionBody Transform(CallExpression call)
             if (!_nameResolver.TryResolveFunctionName(call.OperatorName, out var m))
                 throw new ArgumentException($"The function name `{call.OperatorName}` was not recognized.");
 
-            var methodParameters = m.GetParameters();
+            var methodParameters = m.GetParameters()
+                .Select(info => (pi: info, optional: info.GetCustomAttribute<OptionalAttribute>() != null))
+                .ToList();
 
-            var parameterCount = methodParameters.Count(pi => pi.ParameterType == typeof(LogEventPropertyValue));
-            if (parameterCount != call.Operands.Length)
-                throw new ArgumentException($"The function `{call.OperatorName}` requires {parameterCount} arguments.");
+            var allowedParameters = methodParameters.Where(info => info.pi.ParameterType == typeof(LogEventPropertyValue)).ToList();
+            var requiredParameterCount = allowedParameters.Count(info => !info.optional);
+
+            if (call.Operands.Length < requiredParameterCount || call.Operands.Length > allowedParameters.Count)
+            {
+                var requirements = DescribeRequirements(allowedParameters.Select(info => (info.pi.Name!, info.optional)).ToList());
+                throw new ArgumentException($"The function `{call.OperatorName}` {requirements}.");
+            }
 
             var operands = new Queue<LX>(call.Operands.Select(Transform));
 
@@ -116,11 +126,15 @@ protected override ExpressionBody Transform(CallExpression call)
             if (Operators.SameOperator(call.OperatorName, Operators.RuntimeOpOr))
                 return CompileLogical(LX.OrElse, operands.Dequeue(), operands.Dequeue());
 
-            var boundParameters = new List<LX>(methodParameters.Length);
-            foreach (var pi in methodParameters)
+            var boundParameters = new List<LX>(methodParameters.Count);
+            foreach (var (pi, optional) in methodParameters)
             {
                 if (pi.ParameterType == typeof(LogEventPropertyValue))
-                    boundParameters.Add(operands.Dequeue());
+                {
+                    boundParameters.Add(operands.Count > 0
+                        ? operands.Dequeue()
+                        : LX.Constant(null, typeof(LogEventPropertyValue)));
+                }
                 else if (pi.ParameterType == typeof(StringComparison))
                     boundParameters.Add(LX.Constant(call.IgnoreCase ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal));
                 else if (pi.ParameterType == typeof(IFormatProvider))
@@ -129,13 +143,38 @@ protected override ExpressionBody Transform(CallExpression call)
                     boundParameters.Add(LX.Property(Context, EvaluationContextLogEventProperty));
                 else if (_nameResolver.TryBindFunctionParameter(pi, out var binding))
                     boundParameters.Add(LX.Constant(binding, pi.ParameterType));
+                else if (optional)
+                    boundParameters.Add(LX.Constant(
+                        pi.GetCustomAttribute<DefaultParameterValueAttribute>()?.Value, pi.ParameterType));
                 else
-                    throw new ArgumentException($"The method `{m.Name}` implementing function `{call.OperatorName}` has parameter `{pi.Name}` which could not be bound.");
+                    throw new ArgumentException($"The method `{m.Name}` implementing function `{call.OperatorName}` has argument `{pi.Name}` which could not be bound.");
             }
 
             return LX.Call(m, boundParameters);
         }
 
+        static string DescribeRequirements(IReadOnlyList<(string name, bool optional)> parameters)
+        {
+            static string DescribeArgument((string name, bool optional) p) =>
+                $"`{p.name}`" + (p.optional ? " (optional)" : "");
+
+            if (parameters.Count == 0)
+                return "accepts no arguments";
+
+            if (parameters.Count == 1)
+                return $"accepts one argument, {DescribeArgument(parameters[0])}";
+
+            if (parameters.Count == 2)
+                return $"accepts two arguments, {DescribeArgument(parameters[0])} and {DescribeArgument(parameters[1])}";
+
+            var result = new StringBuilder("accepts arguments");
+            for (var i = 0; i < parameters.Count - 1; ++i)
+                result.Append($" {DescribeArgument(parameters[i])},");
+
+            result.Append($" and {DescribeArgument(parameters[parameters.Count - 1])}");
+            return result.ToString();
+        }
+
         static ExpressionBody CompileLogical(Func<ExpressionBody, ExpressionBody, ExpressionBody> apply, ExpressionBody lhs, ExpressionBody rhs)
         {
             return LX.Convert(

src/Serilog.Expressions/Expressions/Compilation/Variadics/VariadicCallRewriter.cs

@@ -18,7 +18,7 @@
 
 namespace Serilog.Expressions.Compilation.Variadics
 {
-    // Now a bit of a misnomer - handles variadic `coalesce()`, as well as optional arguments for other functions.
+    // Handles variadic `coalesce()` and `concat()`, as well as optional arguments for other functions.
     class VariadicCallRewriter : IdentityTransformer
     {
         static readonly VariadicCallRewriter Instance = new VariadicCallRewriter();
@@ -30,19 +30,11 @@ public static Expression Rewrite(Expression expression)
 
         protected override Expression Transform(CallExpression call)
         {
-            if (Operators.SameOperator(call.OperatorName, Operators.OpSubstring) && call.Operands.Length == 2)
-            {
-                var operands = call.Operands
-                    .Select(Transform)
-                    .Concat(new[] {CallUndefined()})
-                    .ToArray();
-                return new CallExpression(call.IgnoreCase, call.OperatorName, operands);
-            }
-
-            if (Operators.SameOperator(call.OperatorName, Operators.OpCoalesce))
+            if (Operators.SameOperator(call.OperatorName, Operators.OpCoalesce) ||
+                Operators.SameOperator(call.OperatorName, Operators.OpConcat))
             {
                 if (call.Operands.Length == 0)
-                    return CallUndefined();
+                    return new CallExpression(false, Operators.OpUndefined);
                 if (call.Operands.Length == 1)
                     return Transform(call.Operands.Single());
                 if (call.Operands.Length > 2)
@@ -53,18 +45,7 @@ protected override Expression Transform(CallExpression call)
                 }
             }
 
-            if (Operators.SameOperator(call.OperatorName, Operators.OpToString) &&
-                call.Operands.Length == 1)
-            {
-                return new CallExpression(call.IgnoreCase, call.OperatorName, call.Operands[0], CallUndefined());
-            }
-
             return base.Transform(call);
         }
-
-        static CallExpression CallUndefined()
-        {
-            return new CallExpression(false, Operators.OpUndefined);
-        }
     }
 }

src/Serilog.Expressions/Expressions/Operators.cs

@@ -29,6 +29,7 @@ static class Operators
         // RuntimeOp* means runtime only.
 
         public const string OpCoalesce = "Coalesce";
+        public const string OpConcat = "Concat";
         public const string OpContains = "Contains";
         public const string OpElementAt = "ElementAt";
         public const string OpEndsWith = "EndsWith";