An implementation of named string replacements, which allows formatting, parsing, and capturing properties. MessageTemplates is compatible with the Serilog template format.
The C# implementation was extracted from Serilog itself.
The F# implementation was designed to be copied (or paket github referenced) into existing libraries or applications directly, however there may also be a Nuget package in the future.
type User = { Id:int; Name:string }
format (parse "Hello, {@user}") [| {Id=1; Name="Adam"} |]
// > val it : string = "Hello, User { Id: 1, Name: "Adam" }"class Chair {
public string Back { get { return "straight"; } }
public int[] Legs { get { return new[] { 1, 2, 3, 4 }; } }
public override string ToString() { return "a chair"; }
}
Assert.Equal(
"I sat at Chair { Back: \"straight\", Legs: [1, 2, 3, 4] }",
MessageTemplate.Format("I sat at {@Chair}", new Chair()));Message templates are a superset of standard .NET format strings, so any format string acceptable to string.Format() will also be correctly processed by MessageTemplates.
- Property names are written between
{and}brackets - Brackets can be escaped by doubling them, e.g.
{{will be rendered as{ - Formats that use numeric property names, like
{0}and{1}exclusively, will be matched with theFormatmethod's parameters by treating the property names as indexes; this is identical tostring.Format()'s behaviour - If any of the property names are non-numeric, then all property names will be matched from left-to-right with the
Formatmethod's parameters - Property names may be prefixed with an optional operator,
@or$, to control how the property is serialised - Property names may be suffixed with an optional format, e.g.
:000, to control how the property is rendered; these format strings behave exactly as their counterparts within thestring.Format()syntax
public class MessageTemplate
{
public string Text { get; }
public IEnumerable<MessageTemplateToken> Tokens { get; }
public string Render(IReadOnlyDictionary<string, TemplatePropertyValue> properties, IFormatProvider formatProvider = null) { }
public void Render(IReadOnlyDictionary<string, TemplatePropertyValue> properties, TextWriter output, IFormatProvider formatProvider = null) { }
public void Format(IFormatProvider formatProvider, TextWriter output, params object[] values) { }
public string Format(IFormatProvider formatProvider, params object[] values) { }
public static MessageTemplate Parse(string templateMessage) { }
public static IEnumerable<TemplateProperty> Capture(
string templateMessage, params object[] values) { }
public static IEnumerable<TemplateProperty> Capture(
MessageTemplate template, params object[] values) { }
public static IEnumerable<TemplateProperty> CaptureWith(
int maximumDepth, IEnumerable<Type> additionalScalarTypes,
IEnumerable<Core.IDestructuringPolicy> additionalDestructuringPolicies,
MessageTemplate template, params object[] values) { }
public static string Format(string templateMessage, params object[] values)
public static void Format(
IFormatProvider formatProvider, TextWriter output, string templateMessage, params object[] values) { }
public static string Format(
IFormatProvider formatProvider, string templateMessage, params object[] values)
}/// Parses a message template string.
val parse: template:string -> Template
/// Extracts the properties for a template from the array of objects.
val captureProperties: template:Template -> args:obj[] -> PropertyNameAndValue seq
/// Extracts the properties from a message template and the array of objects.
val captureMessageProperties: template:string -> args:obj[] -> PropertyNameAndValue seq
/// Formats a message template as a string, replacing the properties
/// with the provided values.
val format: template:Template -> values:obj[] -> string
/// Prints the message template to a string builder.
val bprintsm: sb:System.Text.StringBuilder -> template:string -> args:obj[] -> unit
/// Prints the message template to a string.
val sprintsm: provider:System.IFormatProvider -> template:string -> args:obj[] -> string
/// Prints the message template a text writer.
val fprintsm: tw:System.IO.TextWriter -> template:string -> args:obj[] -> unit
/// Prints the message template to a string builder.
val bprintm: template:Template -> sb:System.Text.StringBuilder -> args:obj[] -> unit
/// Prints the message template to a string.
val sprintm: template:Template -> provider:System.IFormatProvider -> args:obj[] -> string
/// Prints the message template a text writer.
val fprintm: template:Template -> tw:System.IO.TextWriter -> args:obj[] -> unit