ANSI terminal themes; culture-specific formatting (#38)

* Pass theme through at compile time
* Exception rendering
* Themed JSON
* Nullability juggling
* Themed message templates
* Missing license headers
* Construction of themes from existing themes

* Finish off some TODOs; thread IFormatProvider through consistently; fixes #19

* Sample tidy-up

* Tiny sample tweak

Author: nblumhardt

example/Sample/Program.cs

@@ -1,7 +1,9 @@
 using System;
+using System.Collections.Generic;
 using Serilog;
 using Serilog.Debugging;
 using Serilog.Templates;
+using Serilog.Templates.Themes;
 
 namespace Sample
 {
@@ -24,7 +26,8 @@ static void TextFormattingExample1()
                 .WriteTo.Console(new ExpressionTemplate(
                     "[{@t:HH:mm:ss} {@l:u3}" +
                     "{#if SourceContext is not null} ({Substring(SourceContext, LastIndexOf(SourceContext, '.') + 1)}){#end}] " +
-                    "{@m} (first item is {coalesce(Items[0], '<empty>')})\n{@x}"))
+                    "{@m} (first item is {coalesce(Items[0], '<empty>')})\n{@x}",
+                    theme: TemplateTheme.Code))
                 .CreateLogger();
 
             log.Information("Running {Example}", nameof(TextFormattingExample1));
@@ -41,7 +44,7 @@ static void JsonFormattingExample()
             using var log = new LoggerConfiguration()
                 .Enrich.WithProperty("Application", "Example")
                 .WriteTo.Console(new ExpressionTemplate(
-                    "{ {@t, @mt, @l: if @l = 'Information' then undefined() else @l, @x, ..@p} }\n"))
+                    "{ {@t: UtcDateTime(@t), @mt, @l: if @l = 'Information' then undefined() else @l, @x, ..@p} }\n"))
                 .CreateLogger();
 
             log.Information("Running {Example}", nameof(JsonFormattingExample));
@@ -75,23 +78,35 @@ static void PipelineComponentExample()
 
         static void TextFormattingExample2()
         {
+            // Emulates `Microsoft.Extensions.Logging`'s `ConsoleLogger`.
+            
+            var melon = new TemplateTheme(TemplateTheme.Literate, new Dictionary<TemplateThemeStyle, string>
+            {
+                // `Information` is dark green in MEL.
+                [TemplateThemeStyle.LevelInformation] = "\x1b[38;5;34m",
+                [TemplateThemeStyle.String] = "\x1b[38;5;159m",
+                [TemplateThemeStyle.Number] = "\x1b[38;5;159m"
+            });
+
             using var log = new LoggerConfiguration()
                 .WriteTo.Console(new ExpressionTemplate(
                     "{@l:w4}: {SourceContext}\n" +
                     "{#if Scope is not null}" +
                     "      {#each s in Scope}=> {s}{#delimit} {#end}\n" +
                     "{#end}" +
                     "      {@m}\n" +
-                    "{@x}"))
+                    "{@x}",
+                    theme: melon))
                 .CreateLogger();
 
             var program = log.ForContext<Program>();
-            program.Information("Starting up");
+            program.Information("Host listening at {ListenUri}", "https://hello-world.local");
 
-            // Emulate data produced by the Serilog.AspNetCore integration
-            var scoped = program.ForContext("Scope", new[] {"Main", "TextFormattingExample2()"});
+            program
+                .ForContext("Scope", new[] {"Main", "TextFormattingExample2()"})
+                .Information("HTTP {Method} {Path} responded {StatusCode} in {Elapsed:0.000} ms", "GET", "/api/hello", 200, 1.23);
 
-            scoped.Information("Hello, world!");
+            program.Warning("We've reached the end of the line");
         }
     }
 }

example/Sample/Sample.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
 

serilog-expressions.sln.DotSettings

@@ -1,6 +1,7 @@
 <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: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>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Enricher/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Evaluatable/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Existentials/@EntryIndexedValue">True</s:Boolean>

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

@@ -1,4 +1,18 @@
-using System;
+// Copyright © Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
 
 namespace Serilog.Expressions.Ast
 {

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

@@ -1,16 +1,30 @@
-using System;
+// Copyright © Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
 
 namespace Serilog.Expressions.Ast
 {
     class AmbientNameExpression : Expression
     {
         readonly bool _requiresEscape;
 
-        public AmbientNameExpression(string Name, bool isBuiltIn)
+        public AmbientNameExpression(string name, bool isBuiltIn)
         {
-            PropertyName = Name ?? throw new ArgumentNullException(nameof(Name));
+            PropertyName = name ?? throw new ArgumentNullException(nameof(name));
             IsBuiltIn = isBuiltIn;
-            _requiresEscape = !SerilogExpression.IsValidIdentifier(Name);
+            _requiresEscape = !SerilogExpression.IsValidIdentifier(name);
         }
 
         public string PropertyName { get; }

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

@@ -1,4 +1,18 @@
-using System;
+// Copyright © Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
 using System.Linq;
 
 namespace Serilog.Expressions.Ast

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

@@ -1,4 +1,18 @@
-using System;
+// Copyright © Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
 using System.Linq;
 
 namespace Serilog.Expressions.Ast

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

@@ -1,4 +1,18 @@
-using System;
+// Copyright © Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
 using System.Globalization;
 using Serilog.Events;
 

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

@@ -1,4 +1,18 @@
-namespace Serilog.Expressions.Ast
+// Copyright © Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+namespace Serilog.Expressions.Ast
 {
     abstract class Element
     {

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

@@ -1,4 +1,18 @@
-namespace Serilog.Expressions.Ast
+// Copyright © Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+namespace Serilog.Expressions.Ast
 {
     abstract class Expression
     {