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Merge pull request #109 from nblumhardt/capture-function
Add the `Inspect()` function
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‎README.md

Lines changed: 28 additions & 23 deletions
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@@ -137,6 +137,10 @@ The following properties are available in expressions:
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The built-in properties mirror those available in the CLEF format.
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The exception property `@x` is treated as a scalar and will appear as a string when formatted into text. The properties of
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the underlying `Exception` object can be accessed using `Inspect()`, for example `Inspect(@x).Message`, and the type of the
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exception retrieved using `TypeOf(@x)`.
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### Literals
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| Data type | Description | Examples |
@@ -183,29 +187,30 @@ calling a function will be undefined if:
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* any argument is undefined, or
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* any argument is of an incompatible type.
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| Function | Description |
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| :--- | :--- |
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| `Coalesce(p0, p1, [..pN])` | Returns the first defined, non-null argument. |
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| `Concat(s0, s1, [..sN])` | Concatenate two or more strings. |
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| `Contains(s, t)` | Tests whether the string `s` contains the substring `t`. |
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| `ElementAt(x, i)` | Retrieves a property of `x` by name `i`, or array element of `x` by numeric index `i`. |
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| `EndsWith(s, t)` | Tests whether the string `s` ends with substring `t`. |
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| `IndexOf(s, t)` | Returns the first index of substring `t` in string `s`, or -1 if the substring does not appear. |
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| `IndexOfMatch(s, p)` | Returns the index of the first match of regular expression `p` in string `s`, or -1 if the regular expression does not match. |
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| `IsMatch(s, p)` | Tests whether the regular expression `p` matches within the string `s`. |
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| `IsDefined(x)` | Returns `true` if the expression `x` has a value, including `null`, or `false` if `x` is undefined. |
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| `LastIndexOf(s, t)` | Returns the last index of substring `t` in string `s`, or -1 if the substring does not appear. |
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| `Length(x)` | Returns the length of a string or array. |
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| `Now()` | Returns `DateTimeOffset.Now`. |
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| `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. |
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| `Round(n, m)` | Round the number `n` to `m` decimal places. |
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| `StartsWith(s, t)` | Tests whether the string `s` starts with substring `t`. |
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| `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. |
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| `TagOf(o)` | Returns the `TypeTag` field of a captured object (i.e. where `TypeOf(x)` is `'object'`). |
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| `ToString(x, [format])` | Convert `x` to a string, applying the format string `format` if `x` is `IFormattable`. |
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| `TypeOf(x)` | Returns a string describing the type of expression `x`: a .NET type name if `x` is scalar and non-null, or, `'array'`, `'object'`, `'dictionary'`, `'null'`, or `'undefined'`. |
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| `Undefined()` | Explicitly mark an undefined value. |
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| `UtcDateTime(x)` | Convert a `DateTime` or `DateTimeOffset` into a UTC `DateTime`. |
190+
| Function | Description |
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|:--------------------------------|:------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| `Coalesce(p0, p1, [..pN])` | Returns the first defined, non-null argument. |
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| `Concat(s0, s1, [..sN])` | Concatenate two or more strings. |
194+
| `Contains(s, t)` | Tests whether the string `s` contains the substring `t`. |
195+
| `ElementAt(x, i)` | Retrieves a property of `x` by name `i`, or array element of `x` by numeric index `i`. |
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| `EndsWith(s, t)` | Tests whether the string `s` ends with substring `t`. |
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| `IndexOf(s, t)` | Returns the first index of substring `t` in string `s`, or -1 if the substring does not appear. |
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| `IndexOfMatch(s, p)` | Returns the index of the first match of regular expression `p` in string `s`, or -1 if the regular expression does not match. |
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| `Inspect(o, [deep])` | Read properties from an object captured as the scalar value `o`. |
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| `IsMatch(s, p)` | Tests whether the regular expression `p` matches within the string `s`. |
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| `IsDefined(x)` | Returns `true` if the expression `x` has a value, including `null`, or `false` if `x` is undefined. |
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| `LastIndexOf(s, t)` | Returns the last index of substring `t` in string `s`, or -1 if the substring does not appear. |
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| `Length(x)` | Returns the length of a string or array. |
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| `Now()` | Returns `DateTimeOffset.Now`. |
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| `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. |
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| `Round(n, m)` | Round the number `n` to `m` decimal places. |
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| `StartsWith(s, t)` | Tests whether the string `s` starts with substring `t`. |
208+
| `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. |
209+
| `TagOf(o)` | Returns the `TypeTag` field of a captured object (i.e. where `TypeOf(x)` is `'object'`). |
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| `ToString(x, [format])` | Convert `x` to a string, applying the format string `format` if `x` is `IFormattable`. |
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| `TypeOf(x)` | Returns a string describing the type of expression `x`: a .NET type name if `x` is scalar and non-null, or, `'array'`, `'object'`, `'dictionary'`, `'null'`, or `'undefined'`. |
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| `Undefined()` | Explicitly mark an undefined value. |
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| `UtcDateTime(x)` | Convert a `DateTime` or `DateTimeOffset` into a UTC `DateTime`. |
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Functions that compare text accept an optional postfix `ci` modifier to select case-insensitive comparisons:
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‎src/Serilog.Expressions/Expressions/Operators.cs

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Original file line numberDiff line numberDiff line change
@@ -33,6 +33,7 @@ static class Operators
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public const string OpEndsWith = "EndsWith";
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public const string OpIndexOf = "IndexOf";
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public const string OpIndexOfMatch = "IndexOfMatch";
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public const string OpInspect = "Inspect";
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public const string OpIsMatch = "IsMatch";
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public const string OpIsDefined = "IsDefined";
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public const string OpLastIndexOf = "LastIndexOf";

‎src/Serilog.Expressions/Expressions/Runtime/RuntimeOperators.cs

Lines changed: 40 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -12,6 +12,8 @@
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// See the License for the specific language governing permissions and
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// limitations under the License.
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using System.Reflection;
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using Serilog.Debugging;
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using Serilog.Events;
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using Serilog.Expressions.Compilation.Linq;
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using Serilog.Templates.Rendering;
@@ -538,4 +540,41 @@ public static LogEventPropertyValue _Internal_IsNotNull(LogEventPropertyValue? v
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// DateTimeOffset.Now is the generator for LogEvent.Timestamp.
539541
return new ScalarValue(DateTimeOffset.Now);
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}
541-
}
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public static LogEventPropertyValue? Inspect(LogEventPropertyValue? value, LogEventPropertyValue? deep = null)
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{
546+
if (value is not ScalarValue { Value: {} toCapture })
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return value;
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var result = new List<LogEventProperty>();
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var logger = new LoggerConfiguration().CreateLogger();
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var properties = toCapture.GetType()
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.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.GetProperty);
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foreach (var property in properties)
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{
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object? p;
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try
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{
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p = property.GetValue(toCapture);
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}
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catch (Exception ex)
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{
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SelfLog.WriteLine("Serilog.Expressions Inspect() target property threw exception: {0}", ex);
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continue;
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}
566+
567+
if (deep is ScalarValue { Value: true })
568+
{
569+
if (logger.BindProperty(property.Name, p, destructureObjects: true, out var bound))
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result.Add(bound);
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}
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else
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{
574+
result.Add(new LogEventProperty(property.Name, new ScalarValue(p)));
575+
}
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}
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return new StructureValue(result);
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}
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}

‎test/Serilog.Expressions.Tests/Cases/expression-evaluation-cases.asv

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Original file line numberDiff line numberDiff line change
@@ -264,6 +264,7 @@ typeof(true) ⇶ 'System.Boolean'
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typeof(null) ⇶ 'null'
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typeof([]) ⇶ 'array'
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typeof({}) ⇶ 'object'
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typeof(@x) ⇶ 'System.DivideByZeroException'
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// UtcDateTime
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tostring(utcdatetime(now()), 'o') like '20%' ⇶ true
@@ -313,3 +314,6 @@ tostring(@x) like 'System.DivideByZeroException%' ⇶ true
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@l ⇶ 'Warning'
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@sp ⇶ 'bb1111820570b80e'
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@tr ⇶ '1befc31e94b01d1a473f63a7905f6c9b'
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// Inspect
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inspect(@x).Message ⇶ 'Attempted to divide by zero.'

‎test/Serilog.Expressions.Tests/Expressions/Runtime/RuntimeOperatorsTests.cs

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@@ -0,0 +1,39 @@
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using System.Reflection;
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using Serilog.Events;
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using Serilog.Expressions.Runtime;
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using Serilog.Expressions.Tests.Support;
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using Xunit;
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7+
namespace Serilog.Expressions.Tests.Expressions.Runtime;
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public class RuntimeOperatorsTests
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{
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[Fact]
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public void InspectReadsPublicPropertiesFromScalarValue()
13+
{
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var message = Some.String();
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var ex = new DivideByZeroException(message);
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var scalar = new ScalarValue(ex);
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var inspected = RuntimeOperators.Inspect(scalar);
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var structure = Assert.IsType<StructureValue>(inspected);
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var asProperties = structure.Properties.ToDictionary(p => p.Name, p => p.Value);
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Assert.Contains("Message", asProperties);
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Assert.Contains("StackTrace", asProperties);
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var messageResult = Assert.IsType<ScalarValue>(asProperties["Message"]);
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Assert.Equal(message, messageResult.Value);
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}
25+
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[Fact]
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public void DeepInspectionReadsSubproperties()
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{
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var innerMessage = Some.String();
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var inner = new DivideByZeroException(innerMessage);
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var ex = new TargetInvocationException(inner);
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var scalar = new ScalarValue(ex);
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var inspected = RuntimeOperators.Inspect(scalar, deep: new ScalarValue(true));
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var structure = Assert.IsType<StructureValue>(inspected);
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var innerStructure = Assert.IsType<StructureValue>(structure.Properties.Single(p => p.Name == "InnerException").Value);
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var innerMessageValue = Assert.IsType<ScalarValue>(innerStructure.Properties.Single(p => p.Name == "Message").Value);
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Assert.Equal(innerMessage, innerMessageValue.Value);
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}
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}

‎test/Serilog.Expressions.Tests/Support/Some.cs

Lines changed: 14 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -5,6 +5,8 @@ namespace Serilog.Expressions.Tests.Support;
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static class Some
77
{
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static int _next;
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public static LogEvent InformationEvent(string messageTemplate = "Hello, world!", params object?[] propertyValues)
911
{
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return LogEvent(LogEventLevel.Information, messageTemplate, propertyValues);
@@ -29,11 +31,21 @@ public static LogEvent LogEvent(LogEventLevel level, string messageTemplate = "H
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public static object AnonymousObject()
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{
32-
return new {A = 42};
34+
return new {A = Int()};
3335
}
3436

3537
public static LogEventPropertyValue LogEventPropertyValue()
3638
{
3739
return new ScalarValue(AnonymousObject());
3840
}
39-
}
41+
42+
static int Int()
43+
{
44+
return Interlocked.Increment(ref _next);
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}
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public static string String()
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{
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return $"+S_{Int()}";
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}
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}

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