git clone https://github.com/yang-sanmu/EasyExpression.git
cd EasyExpression
dotnet build
🚀 Quick Start
Basic Usage
using EasyExpression.Core.Engine;
// Create engine
var factory = new DefaultExpressionEngineFactory();
var engine = factory.Create();
// Define input fields
var inputs = new Dictionary<string, object?>
{
{ "price", 100m },
{ "quantity", 5 }
};
// Execute script
var script = @"
{
set(total, [price:decimal] * [quantity:decimal])
set(discount, [total] * 0.1)
set(finalPrice, [total] - [discount])
}";
var result = engine.Execute(script, inputs);
// Access results
Console.WriteLine(result.Assignments["total"]); // 500
Console.WriteLine(result.Assignments["discount"]); // 50
Console.WriteLine(result.Assignments["finalPrice"]); // 450
Script Validation
var validationResult = engine.Validate(script);
if (!validationResult.Success)
{
Console.WriteLine($"Error at line {validationResult.ErrorLine}: {validationResult.ErrorMessage}");
}
📖 Language Syntax
Data Types
Type
Example
Number (decimal)
123, 45.67, -10
String
'hello', "world"
Boolean
true, false
DateTime
now (current time)
Null
null
Operators
Category
Operators
Arithmetic
+, -, *, /, %
Comparison
==, !=, >, <, >=, <=
Logical
&&, ||, !
Field References
Access input fields using square brackets:
[fieldName] // Basic reference
[fieldName:decimal] // With type annotation
[fieldName:datetime] // DateTime type
[fieldName:bool] // Boolean type
[fieldName:string] // String type
Statements
Set Statement
set(variableName, expression)
set(variableName:type, expression) // With type annotation
public class MyFunction : IFunction
{
public string Name => "MyFunc";
public object? Invoke(object?[] args, InvocationContext ctx)
{
// Implementation
return args[0]?.ToString()?.ToUpperInvariant();
}
}
// Register via contributor
public class MyContributor : IEngineContributor
{
public void Configure(EngineServices services)
{
services.Functions.Register(new MyFunction());
}
}
// Use contributor
var engine = factory.Create(contributors: new[] { new MyContributor() });
Custom Type Converters
public class MyConverter : ITypeConverter
{
public Type InputType => typeof(string);
public Type OutputType => typeof(MyType);
public bool TryConvert(object? value, out object? result)
{
// Conversion logic
}
}
// Register in contributor
services.Converters.Register(new MyConverter());
📊 Execution Result
var result = engine.Execute(script, inputs);
// Check for errors
if (result.HasError)
{
Console.WriteLine($"Error: {result.ErrorMessage}");
Console.WriteLine($"Location: Line {result.ErrorLine}, Column {result.ErrorColumn}");
Console.WriteLine($"Code: {result.ErrorSnippet}");
Console.WriteLine($"Error Code: {result.ErrorCode}");
}
// Access assigned variables
foreach (var kvp in result.Assignments)
{
Console.WriteLine($"{kvp.Key} = {kvp.Value}");
}
// Access messages
foreach (var msg in result.Messages)
{
Console.WriteLine($"[{msg.Level}] {msg.Text}");
}
// Execution time
Console.WriteLine($"Elapsed: {result.Elapsed}");
