CppAst.NET

CppAst provides a C/C++ parser for header files with access to a managed AST model, comments and macros for .NET.

Purpose

The target primary usage of this library is to serve as a simple foundation for domain oriented PInvoke/Interop codegen

Features

• Compatible with net8.0
  • For netstandard2.0 use 0.14.0 version.
• Uses Clang/libclang 21.1.8.x through ClangSharp
• Parses in-memory C/C++ text and C/C++ files from disk
• Supports C, C++ and Objective-C language modes via CppParserOptions.ParserKind
• Simple managed AST model with declarations for namespaces, classes/structs/unions, Objective-C interfaces, enums, fields/global variables, functions/methods, typedefs/using aliases and include directives
• Broad type system for primitive, record, enum, typedef, pointer, reference, array, function, block-function, qualified, template and unexposed/dependent types
• C++ support for common class, inheritance, constructor/destructor, operator, conversion, friend, inline/final/defaulted/deleted, template and specialization metadata
• Provides access to system/annotate attributes, optional token-level attributes (CppParserOptions.ParseTokenAttributes) and comment-based attributes (CppParserOptions.ParseCommentAttribute)
• Provides access to attached comments, including Doxygen comments and parameter comment commands
• Provides access to expressions for variable initializers and default parameter values (e.g. const int x = (1 + 2) << 1 exposes the initializer expression)
• Provides function body source spans with CppParserOptions.ParseFunctionBodies (not a full statement-body AST)
• Provides access to macro definitions, parameters and tokens via CppParserOptions.ParseMacros (default is false)
• Provides target configuration helpers such as ConfigureForWindowsMsvc(...) and ParseSystemIncludes filtering for system headers

Documentation

Check the user guide documentation from the doc/ folder.

Usage Example

Setup

After installing the NuGet package, configure your project to select a platform RID via the RuntimeIdentifier property so the native libclang asset is restored:

  <PropertyGroup>
    <!-- Workaround for issue https://github.com/microsoft/ClangSharp/issues/129 -->
    <RuntimeIdentifier Condition="'$(RuntimeIdentifier)' == '' AND '$(PackAsTool)' != 'true'">$(NETCoreSdkRuntimeIdentifier)</RuntimeIdentifier>
  </PropertyGroup>

Code

You can jump-start with the CppParser.Parse method:

// Parse C++ files
var compilation = CppParser.Parse(@"
enum MyEnum { MyEnum_0, MyEnum_1 };
void function0(int a, int b);
struct MyStruct { int field0; int field1;};
typedef MyStruct* MyStructPtr;
"
);
// Print diagnostic messages
foreach (var message in compilation.Diagnostics.Messages)
    Console.WriteLine(message);

// Print All enums
foreach (var cppEnum in compilation.Enums)
    Console.WriteLine(cppEnum);

// Print All functions
foreach (var cppFunction in compilation.Functions)
    Console.WriteLine(cppFunction);

// Print All classes, structs
foreach (var cppClass in compilation.Classes)
    Console.WriteLine(cppClass);

// Print All typedefs
foreach (var cppTypedef in compilation.Typedefs)
    Console.WriteLine(cppTypedef);

Prints the following result:

enum MyEnum {...}
void function0(int a, int b)
struct MyStruct { ... }
typedef MyStruct* MyStructPtr

Binaries

This library is distributed as a NuGet package

Known issues

CppAst is a lightweight model over libclang and intentionally does not expose every Clang cursor or statement node. Some known limitations are:

• Function bodies are exposed as source spans when requested, not as a full statement AST.
• Template/dependent/unexposed types are represented on a best-effort basis and may require inspecting CppUnexposedType, display names or diagnostics for advanced C++ constructs.
• Token-level attributes are still available for compatibility but are obsolete; prefer system/annotate attributes when possible.
• Type sizes and built-in aliases such as size_t follow the configured target triple/ABI.

License

This software is released under the BSD-Clause 2 license.

Credits

• ClangSharp: .NET managed wrapper around Clang/libclang

Related

The C++ project cppast serves similar purpose although CppAst.NET does not share API or any implementation details.

Author

Alexandre Mutel aka xoofx.