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Rule Templates

Reusable rule templates with placeholders for type-safe rule generation.

using RoslynRules.Templates;

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RuleTemplate

public class RuleTemplate

Properties

Property	Type	Description
Description	string	Template description
Expression	string	Expression template with {placeholder} syntax
Action	string	Action template (optional)
Placeholders	Dictionary<string, PlaceholderKind>	Defined placeholders

Methods

Instantiate(Dictionary<string, object>, ExpressionCompiler, RuleParameter[], string[]?)

Creates a compiled Rule from the template with placeholder values substituted.

var template = new RuleTemplate
{
    Description = "Age threshold",
    Expression = "customer.Age >= {minAge}"
};
template.Placeholders.Add("minAge", PlaceholderKind.Value);

var values = new Dictionary<string, object> { ["minAge"] = 18 };
var rule = template.Instantiate(values, compiler, parameters, Array.Empty<string>());

ExtractPlaceholders(string)

Extracts placeholder names from an expression string.

var names = RuleTemplate.ExtractPlaceholders("customer.Age >= {minAge} && customer.Score >= {minScore}");
// ["minAge", "minScore"]

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PlaceholderKind

Kind	Substitution	Example
Value	Quoted/escaped value	"Alice", 42, true
Type	Unquoted type name	Customer, System.String
Identifier	Raw text	Name, Age

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Related

• Rule — Produced by template instantiation
• ExpressionCompiler — Required for instantiation