tlin: Lint for gno

Advance Linter for go-like grammar languages.

Introduction

tlin is an linter designed for both Go and gno programming languages. It leverages the functionality of golangci-lint as its main linting engine, providing powerful code analysis for go-like grammar languages.

Inspired by Rust's clippy, tlin aims to provide additional code improvement suggestions beyond the default golangci-lint rules.

Features

• Support for Go (.go) and Gno (.gno) files
• Ability to add custom lint rules
• Additional code improvement suggestion, such as detecting unnecessary code (🚧 WIP)

Installation

• Requirements:
  • Go: 1.22 or higher
  • latest version of gno

To install tlin CLI, run:

go install ./cmd/tlin

Usage

tlin <path>

Replace <path> with the file or directory path you want to analyze.

To check the current directory, run:

tlin .

Adding Custom Lint Rules

tlin allows addition of custom lint rules beyond the default golangci-lint rules. To add a new lint rule, follow these steps:

⚠️ Must update relevant tests if you have added a new rule or formatter.

1. Implement the LintRule interface for your new rule:

type NewRule struct{}

func (r *NewRule) Check(filename string) ([]Issue, error) {
    // Implement your lint rule logic here
    // return a slice of Issues and any error encountered
}

2. Register your new rule in the registerDefaultRules method of the Engine struct in internal/engine.go:

func (e *Engine) registerDefaultRules() {
    e.rules = append(e.rules,
        &GolangciLintRule{},
        // ...
        &NewRule{}, // Add your new rule here
    )
}

3. (Optional) if your rule requires special formatting, create a new formatter in the formatter package:

   a. Create a new file (e.g., formatter/new_rule.go). b. Implement the IssueFormatter interface for your new rule:

   type NewRuleFormatter struct{}
   
   func (f *NewRuleFormatter) Format(
       issue internal.Issue,
       snippet *internal.SourceCode,
   ) string {
       // Implement formatting logic for new rule here.
   }

   c. Add the new formatter to the GetFormatter function in formatter/fmt.go.

   func GetFormatter(rule string) IssueFormatter {
       switch rule {
       // ...
       case "new_rule": // Add your new rule here
           return &NewRuleFormatter{}
       default:
           return &DefaultFormatter{}
       }
   }

By following these steps, you can add new lint rules and ensure they are properly formatted when displayed in the CLI.

Contributing

We welcome all forms of contributions, including bug reports, feature requests, and pull requests. Please feel free to open an issue or submit a pull request.

License

This project is distributed under the MIT License. See LICENSE for more information.