1. Marco Parenzan
marcoparenzan/CodeGenerationForAzureWithDotNet (github.com)

2. Senior Solution Architect in beanTech
Microsoft Azure MVP
Community Lead 1nn0va // Pordenone
1nn0va After Hour
https://bit.ly/1nn0va-video
Linkedin: https://www.linkedin.com/in/marcoparenzan/
Marco Parenzan

5. • Faster upgrades
• Framework (.NET 6.0 anyone?)
• Cloud Services
• Enforce (best) practices
• Increase maintainability
Challenges for the modern cloud company

6. • Service vs. Web Service
• Servicebusiness logic
• Web Serviceprotocol adaptation
• HTTPS vs GRPC
• Azure Function vs. API App
• Develop in front of a component
• Better testing
• Single Responsability Principle!
• Business logic and protocol adaptation are two responsabilities
Value vs. Not Value

7. • “Code that generates code…”
• Reflection
• Powerful
• Difficult to maintain
• Difficult to customize
• DSL
• Powerful
• Difficult to maintain
• Risk to customize
• Code Generation
• Powerful
• Simpler to maintain
• Simpler(?) to customize
Dynamic (Meta)Programming

8. • Text-based code generation
• T4
• Yeoman
• Razor
• Roslyn-based code generation
Code Generation Tecniques

10. CSC/VBC
Opening up the compiler
IL
AST
AST AST

11. Custom Diagnostic - Analyzer
private void Analyzer(SymbolAnalysisContext context)
{
var symbol = (INamedTypeSymbol)context.Symbol;
if (symbol.BaseType == null) return;
if ((symbol.BaseType.Name == "Controller"
|| symbol.BaseType.Name == "ApiController")
&& !symbol.Name.EndsWith("Controller"))
{
var diagnostic = Diagnostic.Create(
Rule, symbol.Locations[0], symbol.Name);
context.ReportDiagnostic(diagnostic);
}
}

12. C# Scripting / Interactive
var script = CSharpScript.Create<int>("int x = 1;")
.ContinueWith("int y = 2;")
.ContinueWith("x + y");
Assert.AreEqual(
3,
(int)(await script.RunAsync()).ReturnValue);

13. Building your own Fix
var value = 1 + 2;
ExpressionSyntax
SyntaxToken
SyntaxTrivia
var equalsValue =
SyntaxFactory.EqualsValueClause(
SyntaxFactory.BinaryExpression(
SyntaxKind.AddExpression,
SyntaxFactory.LiteralExpression(
SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(1)),
SyntaxFactory.LiteralExpression(
SyntaxKind.NumericLiteralExpression,SyntaxFactory.Literal(2))
));
var typeSyntax =
SyntaxFactory.VariableDeclaration(
SyntaxFactory.ParseTypeName("var"),
new SeparatedSyntaxList<VariableDeclaratorSyntax>()
.Add(SyntaxFactory.VariableDeclarator(“value")
.WithInitializer(equalsValue)))
.NormalizeWhitespace(" ")
.WithAdditionalAnnotations(Formatter.Annotation);
var declaration = SyntaxFactory.LocalDeclarationStatement(typeSyntax);

14. • - Extremely verbose
• + (Extremely) Statically Typed
• + Extremely meaningful
• Can be optimizedStatical VS refactoring
• C#6+ Era of immutability
• This is why some C# syntax exists
• Partial classes
• Partial methods
Roslyn code consideration

17. • Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
• Maintenance first!
Conclusions

18. • Creating code generators is not “mainstream”
• Using cg yes…Razor (again) is a code generator
• Don’t increase complexity
• Don’t implement infrequent situations
• manage infrequent situations with traditional classic manual code
• Roslyn
• Mature (everything Roslyn since C# 6.0+)
• Visual Studio Code Generators
• Difficult to test
• Develop outside Analyzer (whenever possible)
• Standard2.0 basedVisual Studio is .NET 4.8 (not core!!!!)
Conclusions

19. Marco Parenzan
marcoparenzan/CodeGenerationForAzureWithDotNet (github.com)