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14 posts tagged with "c#"

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TreeSitter C# bindings - new languages

· 3 min read

I updated my TreeSitter.Bindings packages to support additional languages. I wanted to check how solid the bindings were and if I could implement a more complex sample with the respect to the json one I started with.

The tree-sitter documentation provides a multilanguage sample which involves three languages:

  • embedded template
  • ruby
  • html

Implementing APIs with the visitor pattern

· 4 min read

I want to leverage my visitor pattern source generator to implement a simple minimal api.

I aim to:

  • Have a request and a request handler for my endpoint. I will not use mediatr or any similar library and I will not use any real storage, only some in memory data structure to showcase the visitor pattern approach.
  • The request handler Handle method returns an interface, every subtype represents a different type of result, a success, and one type for each error (provided) emitted by the handled.
  • For each subtype we want to be able to return a possibly different http response.

TreeSitter C# bindings

· 6 min read

In a previous experiment I made I used the LLVMSharp library and I was quite curious on how the bindings are made. In the readme is it stated they are generated using che ClangSharp library, this one auto-generate hitself from the headers of Clang C header.

This functionality is exposed through a dotnet tool: ClangSharpPInvokeGenerator. So I wanted to try and hack my way into parsing the tree-sitter headers and use the generated code to run a very small sample using C#, in particular I was aiming for the one that's in the getting started section of the docs

Visitor pattern source generator

· 5 min read

I am a big fan of the visitor pattern, I think it is a very good approach for adding behaviors to a group of classes without modifying all of them.

For example if we are building a compiler we may have an abstract syntax tree that represents the code that the compiler is compiling. Two different visitors can be, for example:

  • a type checker
  • a code emitter

Using EF6 with SQLite on dotnet core

· 2 min read

In this post we will see how to use EF6 (not EF Core) in a .NET Core application with SQLite. Why we would like to do this? Maybe we are migrating a project from the full framework to .NET Core but we are not ready to migrate also EF6 to EF Core. I will not show how to work with migrations.

First of all, we need to install two packages in our project:

  • System.Data.SQLite.EF6
  • System.Data.SQLite

LLVM Kaleidoscope .NET

· 5 min read

LLVM Kaleidoscope .NET

If you're reading and learning about compilers in these days you will at some point find something about LLVM. I did and I tried to implement the Kaleidoscope tutorial from the official documentation using C#. I won't write a full blown tutorial and in the end I didn't actually follow the official tutorial as it was pretty hard for me to read C++ code.

Workflows with the visitor pattern

· 11 min read

Workflows

As a software developer I work, most of the times, on LOB applications that support some kind of process or workflow for a specific company. That means that there are some entities, such as customers, orders or support tickets, and that they evolve during the lifecycle of the application. For example we could have a CRM with a lead entity that evolves into a customer or we could track the state of a ticket: open -> analysis -> work -> deploy.

Parsing polynomials with the Pratt algorithm

· 4 min read

polynomials-pratt-algorithm

Using a Pratt parser I aim to parse expressions like this x^2+y^2-1, x=1, y=1 and xy, x=2, y=3. Parsing mathematical expressions it's not hard but it already contains some interesting behaviour such as associativity between operators x+y*z is equal to x+(y*z) and not (x+y)*z. For no particular reason I decided to put the variable assignments after the polynomial. The expression x^2+y^2-1, x=1, y=1 is to be interpreted as you would with this pseudo code

Antlr4 polynomial grammar - 2020 update

· 5 min read

Antlr4

A few years back I was playing with Antlr to build a polynomial evaluator. The result was working but not very sofisticated o particularly good, just a minimal working example. In these days of quarantine in Italy, I decided to get back a that project and try to make something better. The final result can be found at this repo.