Category: roslyn

I am a big fan of Roslyn Source Code Generators – you can read about at https://github.com/dotnet/roslyn/blob/main/docs/features/source-generators.md and https://devblogs.microsoft.com/dotnet/introducing-c-source-generators/. I have tested , until now, 27 examples and discovered other 53 RSCG – you can read about at https://github.com/ignatandrei/RSCG_Examples and download the book from  https://ignatandrei.github.io/RSCG_Examples/

Also, Microsoft is dogfooding this by using at Blazor ( https://devblogs.microsoft.com/aspnet/asp-net-core-updates-in-net-6-preview-2/#razor-compiler-updated-to-use-source-generators ), JSON.NET https://devblogs.microsoft.com/dotnet/try-the-new-system-text-json-source-generator/ . This will alleviate some of the pain points from https://turnerj.com/blog/the-pain-points-of-csharp-source-generators .

Now Microsoft is evolving the specification . I have read about Incremental Generators – https://github.com/dotnet/roslyn/blob/main/docs/features/incremental-generators.md . This sounds promising – and the fact that is called “Incremental” , that can generate more than source code and can be cached sounds great. Let’s see !

This will tracing methods marked with AOPMarkerMethod in CI builds. Does not affect the code run by the programmer.
 

The code that you start with is

    using AOPMethodsCommon;

    using System;

    using System.Threading.Tasks;

    

    namespace AOPMarkerCI

    {

        [AutoMethods(template = TemplateMethod.CustomTemplateFile, MethodPrefix = "auto", CustomTemplateFileName = "../AutoMethod.txt")]

        partial class UnderTest

        {

            [AOPMarkerMethod]

            public async Task<int> Method1()

            {

                await Task.Delay(1000);

                var ret = Method2(DateTime.Now);

                return ret % 2 == 0 ? 1 : 0;

            }

            [AOPMarkerMethod]

            private int Method2(DateTime now)

            {

                return now.Second;

            }

    

        }

    }

The code that you will use is

    Console.WriteLine("Run the autoci file");

    var underTest = new UnderTest();

    int i = await underTest.Method1();

    Console.WriteLine($"result:{i}");

The code that is generated is

    //------------------------------------------------------------------------------

    // <auto-generated>

    //     This code was generated by a tool.

    //

    //     Changes to this file may cause incorrect behavior and will be lost if

    //     the code is regenerated.

    // </auto-generated>

    //------------------------------------------------------------------------------

    using System;

    using System.Collections.Generic;

    using System.CodeDom.Compiler;

    using System.Runtime.CompilerServices;

    using System.Diagnostics;

    namespace AOPMarkerCI {

    

        [GeneratedCode("AOPMethods", "2021.6.11.907")]

        [CompilerGenerated]

        public partial class UnderTest{

            //autoMethod1

                

            public  async  System.Threading.Tasks.Task<int> Method1 (){

    

         Console.WriteLine("start method autoMethod1 at " +utcTime);

    

                try{

                     return   await  autoMethod1();

                }

                catch(Exception ex){

                    Console.WriteLine($"--autoMethod1 exception {ex.Message}");

                    throw;

                }

                finally{

                        utcTime =System.DateTime.UtcNow;

                    Console.WriteLine("end method autoMethod1");                

                }

    

    

            }//end Method1

            

                    //autoMethod2

                

            public  int Method2 (System.DateTime now){

                   var utcTime =System.DateTime.UtcNow;

                 

                   Console.WriteLine("start method autoMethod2 at " +utcTime);

                    string valnow ;

                    try{

                        valnow = System.Text.Json.JsonSerializer.Serialize(now);

                    }

                    catch(Exception ex){

                        valnow = "Error serializing parameter now : "+ ex.Message;

                    }

                    Console.WriteLine("Argument_now :" + valnow);

                    

                 

                

    

                try{

                     return   autoMethod2(now);

                }

                catch(Exception ex){

                    Console.WriteLine($"--autoMethod2 exception {ex.Message}");

                    throw;

                }

                finally{

                        utcTime =System.DateTime.UtcNow;

                    Console.WriteLine("end method autoMethod2");                

                }

    

    

            }//end Method2

            

            

        }

     }

    

    

Example Code: https://github.com/ignatandrei/RSCG_Examples/tree/main/AOPMarkerCI

All RSCG

This will generate interface from a class
 

The code that you start with is

    [AutoGenerateInterface]                        

    public partial class Person: IPerson

    {

        public void Foo()

        {

            Console.WriteLine("Foo");

        }

        //dummy

        private string s { get; set; }

        public int ID { get; set; }

        public string Name { get; set; }

        //dummy

        public static string NewID { get; set; }

    }

The code that you will use is

    IPerson p = new Person();

    p.Name = "Andrei";

    p.Foo();

    Console.WriteLine(p.Name);

The code that is generated is

    public interface IPerson {

    public void Foo();

    public int  ID  {get; set; }

    public string  Name  {get; set; }

    }

Example Code: https://github.com/ignatandrei/RSCG_Examples/tree/main/Class2Interface

All RSCG

This will generate code .ToString. Usefull for debugging
 

The code that you start with is

    [StructGenerators.GenerateToString(PrintTypeName = true)]

    class Person

    {

        [Required]

        public string FirstName { get; set; }

        public string LastName { get; set; }

    }

The code that you will use is

    var p = new Person();

    p.FirstName = "Andrei";

    //put here a debug watch to see p

    Console.WriteLine(p.ToString());

The code that is generated is

    partial class Person

    {

        /// <inheritdoc/>

        public override string ToString()

        {

            var sb = new StringBuilder();

            sb.Append("Person ");

            sb.Append("{ ");

            if (PrintMembers(sb))

            {

                sb.Append(" ");

            }

    

            sb.Append("}");

            return sb.ToString(0, Math.Min(sb.Length, /*String rep limit*/ 1024));

        }

    

        /// <summary>

        /// Prints the content of the instance into a given string builder.

        /// </summary>

        protected virtual bool PrintMembers(StringBuilder sb)

        {

            sb.Append("s = ");

            sb.Append((object)s);

            sb.Append(", ");

            sb.Append("ID = ");

            sb.Append(ID);

            sb.Append(", ");

            sb.Append("FirstName = ");

            sb.Append((object)FirstName);

            sb.Append(", ");

            sb.Append("LastName = ");

            sb.Append((object)LastName);

            return true;

        }

    }

Example Code: https://github.com/ignatandrei/RSCG_Examples/tree/main/DebuggerToString

All RSCG