Licensing

This is a paid package, you can use it anywhere if you purchased it.

Introduction

This package provides the API for parsing and expression execution written in C#. It is specially designed to work with the Unity on various platforms. Since it is written in C# 3.5 and has no additional dependencies, it should work with any version of Unity (and .NET framework).

It is tested to work on:

IOS
Android
WebGL
PC/Mac

It should work on any other platforms.

⚠️ For AOT execution platforms (iOS, WebGL, IL2CPP) a link.xml should be added to project's root directory. Read more about IL code stripping in official documentation.

API

CSharpExpression
- Evaluate
- Parse
AotCompilation
- RegisterFunc
- RegisterForFastCall (optional stuff)

Example

Parsing C# expression into System.Linq.Expression.Expression[T]:

var mathExpr = "Math.Max(x, y)";
var exprTree = CSharpExpression.Parse<double, double, double>(mathExpr, arg1Name: "x", arg2Name: "y") 
// exprTree -> Expression<Func<double, double, double>>

Evaluating C# expression:

var arifExpr = "2 * (2 + 3) << 1 + 1 & 7 | 25 ^ 10";
var result = CSharpExpression.Evaluate<int>(arifExpr); 
// result -> 19

Parser

The parser recognizes the C# 4 grammar only. It includes:

Nullable types are supported. Generics are supported. Enumerations are supported. Type inference is not available and your should always specify generic parameters on types and methods.

Known Types

For security reasons the parser does not provide access to any types except:

types used in arguments
primitive types
Math, Array, Func<> types

To access other types your should pass typeResolver parameter in Parse and Evaluate method:

var typeResolver = new KnownTypeResolver(typeof(Mathf), typeof(Time));
CSharpExpression.Evaluate<int>("Mathf.Clamp(Time.time, 1.0f, 3.0f)", typeResolver);

If you want to access all types in UnityEngine you can pass custom AssemblyTypeResolver as typeResolver parameter.

var typeResolver = new AssemblyTypeResolver(typeof(UnityEngine.Application).Assembly);

ℹ️ For security reasons any method/property calls on System.Type will throw exceptions until System.Type is added as known type.

AOT Execution

You can compile and evaluate expression created by System.Linq.Expression and execute it in AOT environment where it is usually impossible.

var expr = (Expression<Func<Vector3>>)(() => new Vector3(1.0f, 1.0f, 1.0f));
var fn = expr.CompileAot();

fn; // -> Func<Vector3>
fn(); // -> Vector3(1.0f, 1.0f, 1.0f)

iOS, WebGL and most console platforms use AOT compilation which imposes following restrictions on the dynamic code execution:

only Expression<Func<...>> delegate type could be used with CompileAot().
only static methods using primitives (int, float, string, object ...) are optimized for fast calls, others are called with reflection.
all used classes/methods/properties should be visible to Unity's static code analyser
⚠️ An additional preparation should be made for AOT execution platforms. This link.xml should be added in project's root folder. Read more about IL code stripping in official documentation.

See Also

WebGL and iOS

Only Func<> (up to 4 arguments) lambdas are supported with CompileAot().
Instance methods calls performs slowly due reflection
Moderate boxing for value types (see roadmap)

You can prepare Func<> lambda for AOT compilation/execution by registering it with AotCompilation.RegisterFunc.

AotCompilation.RegisterFunc<int, bool>(); // will enable Func<int, bool> lambdas anywhere in expressions

Unity 2020.3.2 Issues

This version of Unity has runtime bug related to lambda compilation. Please use following workaround for IL2CPP/AOT runtime:

#if ((UNITY_WEBGL || UNITY_IOS || ENABLE_IL2CPP) && !UNITY_EDITOR)
GameDevWare.Dynamic.Expressions.AotCompilation.IsAotRuntime = true;
#endif

Improving Performance

You can improve the performance of methods invocation by registering their signatures in AotCompilation.RegisterForFastCall().

// Supports up to 3 arguments.
// First generic argument is your class type.
// Last generic argument is return type.

AotCompilation.RegisterForFastCall<InstanceT, ResultT>()
AotCompilation.RegisterForFastCall<InstanceT, Arg1T, ResultT>()
AotCompilation.RegisterForFastCall<InstanceT, Arg1T, Arg2T, ResultT>()
AotCompilation.RegisterForFastCall<InstanceT, Arg1T, Arg2T, Arg3T, ResultT>()

Example:

public class MyVectorMath
{
    public Vector4 Dot(Vector4 vector, Vector4 vector);
    public Vector4 Cross(Vector4 vector, Vector4 vector);
    public Vector4 Scale(Vector4 vector, float scale);    
}

// register Dot and Cross method signatures
AotCompilation.RegisterForFastCall<MyVectorMath, Vector4, Vector4, Vector4>();
// register Scale method signature
AotCompilation.RegisterForFastCall<MyVectorMath, Vector4, float, Vector4>();

Roadmap

You can send suggestions at [email protected]

Expression serialization (in-progress)
Void expressions (System.Action delegates) (done)
Parser: Delegate construction from method reference
Parser: Type inference for generics
Parser: Full C#6 syntax
Parser: Extension methods
Parser: Type initializers, List initializers
Custom editor with auto-completion for Unity

Changes

2.3.0

fix: fixed netcore related error with enumerable.empty
feature: added optional global parameter to all CSharpExpression methods to allow specify global object for expression.
test: removed flaky test with double.tostring() comparison
fix: fixed typo in arg4Name in CSharpExpression.ParseFunc{4} and CSharpExpression.ParseAction{4}

2.2.9

fix: fixed error with instantiated generic method on types (which is impossible in normal conditions, but fine for Unity AOT runtime).

2.2.8

feature:made AotCompilation.IsAotRuntime is mutable, this will allow to signal for AOT runtime and suppress further checks.

2.2.7

feature: added public CSharpExpression.Format method for SyntaxTreeNode

2.2.6

changed order or SyntaxTreeNode fields and added "original C# expression" field to parsed AST.
refactored C# expression rendering to support null-propagation expressions, type aliases (int, byte, object ...),
renamed "Render" methods to "FormatAsCSharp". Now it is "formatting"
moved c# "formatting" methods to CSharpExpression class
mark old "Parse" functions as errors
mark old "Render" methods as obsolete
renamed CSharpExpressionFormatter to CSharpExpressionFormatter
fixed indexer experssion rendering
refactored NameUtils to properly render C# type names

2.2.5

renamed ParseTreeNode.Lexeme to .Token
renamed few member of TokenType for better clarity
added documentation file in Unity project assets
changed 'propertyOrFieldName' attribute to 'name' in SyntaxTreeNode
renamed PropertyOfFieldBinder to MemberBinder
changed 'PropertyOrField' expression type to 'MemberResolve' in SyntaxTreeNode
added backward compatibility checks in all related classes

2.2.4

added protection against wrong expressions like 'a b' which later bound as 'b'
fixed some tokenization errors:
- 'issa'scanned as 'is'[Operator] and 'sa'[Identifier], now as 'issa'
- '.09' scanned as '.'[Operator] and '09'[Number], now as '0.09'
- '0.1x' scanned as '0.1'[Number] and 'x'[Identifier], now cause error
added method calls on numbers (example 1.ToString())
added short number notation (example '.9' for '0.9')
added '@' prefix for identifiers (example '@is') https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/verbatim
done small Tokenizer optimization (reduced string allocation during scanning)

2.2.3

added ExpressionPacker type. This type allows packing/unpacking expressions into primitive structures (Dictionaries, Arrays...). These structures could be serialized and wired by network or stored for future use.
added better error message for some binding cases
denying call to 'Type.InvokeMember' if 'Type' is not within 'known types'.

2.2.2

fixed conditional operator (a ? b : c) parsing with method call in place of 'b'

2.2.1

fixed IL2CPP compilation error due _Attribute interface complilation failure
added few interfaces to AOT.cs file for better AOT coverage

2.2.0

Features

added support for void expressions (Action<> delegates)
added support of '.NET Standart 1.3' and '.NET Core 2.0' platforms

2.1.4

Release version, no actual changes except readme.md

2.1.2-rc

Features

added more descriptive message for member binding error
added autodoc comments for public members
hid ReadOnlyDictionary from public access
removed Unity WebGL #if for unsigned types. Unity's bug was fixed.
added support for generic types and generic methods
added nullable types and ? suffix support

CSharpExpression.Evaluate<int?>("default(int?)"); // -> null

added lambda expressions. Syntax is () => x and new Func(a => x)
added support for expression's parameter re-mapping with lambda expression syntax:

CSharpExpression.Evaluate<int, int, int>("(x,y) => x + y", 2, 2); // -> 4

added support for Func<> lambdas for AOT environments
added additional constructor to Binder class

public Binder(Type lambdaType, ITypeResolver typeResolver = null);

added ArgumentsTree.ToString() method
added aliases for build-in types. Aliases resolved during binding phase inside Binder.Bind() method.

CSharpExpression.Evaluate<int>("int.MaxValue");

Bugs

fixed error with wrongly resolved types (only by name) in KnownTypeResolver
fixed bug with ACCESS_VIOLATION on iOS (Unity 5.x.x IL2CPP)
fixed few Unity 3.4 related errors in code
fixed 'new' expression parsed with error on chained calls new a().b().c()
fixed some cases of lifted binary/unary/conversion operations
fixed some AOT'ed operations on System.Boolean type
fixed null-propagation chains generate invalid code
fixed some edge cases of resolving nested generic types
fixed error with types without type.FullName value
fixed Condition operator types promotion
fixed Power operator types promotion and null-lifting
fixed enum constants threated as underlying types during binary/unary operations

Breaking changes in 2.0

ParserNode renamed to ParseTreeNode
ExpressionTree renamed to SyntaxTreeNode
ExpressionBuilder renamed to Binder
ITypeResolutionService renamed to ITypeResolver
ITypeResolver.GetType removed
ITypeResolver now could be configured with TypeDiscoveryOptions

1.0.1.11

fixed error them creating nullable types via "new" keyword
fixed Embedded Resource addressing problem on IL2CPP WebGL (localized error messages)
fixed some cases of nullable types binding
fixed Enum member resolution
added Power(**) operator into C# syntax

CSharpExpression.Evaluate<int>("2 ** 2"); // -> 4

added TypeResolutionService chaining for better KnownTypes re-use

1.0.1.10

fixed error with nulled constants after first call for AOT-ted expression.
added ToString() impl for ExpressionTree

1.0.1.9

added Null-conditional Operators (example: a.?b.?.c)
fixed array indexing expressions
added array types support in type expressions ('convert', 'typeof', 'is' etc.)

Installation

Nuget:

Install-Package GameDevWare.Dynamic.Expressions

Unity:

Package at Unity Asset Store

Contacts

Please send any questions at [email protected]

License

Asset Store Terms of Service and EULA

deniszykov/csharp-eval-unity3d

deniszykov

Reviews

Repository Details

Licensing

Introduction

Example

Parser

AOT Execution

WebGL and iOS

Unity 2020.3.2 Issues

Roadmap

Changes

2.3.0

2.2.9

2.2.8

2.2.7

2.2.6

2.2.5

2.2.4

2.2.3

2.2.2

2.2.1

2.2.0

2.1.4

2.1.2-rc

Features

Bugs

Breaking changes in 2.0

1.0.1.11

1.0.1.10

1.0.1.9

Installation

Contacts

License

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