validategen-docs

What I do

When validategen is referenced (tool name, GitHub URL, or any question about Go struct validation), I clone the devgen repository locally for thorough analysis to understand:

• •validategen annotation syntax and validation rules
• •Generated Validate() method signatures
• •Supported field types and validation constraints
• •Integration with enumgen (@oneof_enum)

When to use me

• •Any question about validategen or Go struct validation code generation
• •Understanding validategen:@validate annotation syntax
• •Questions about validation rules (@required, @email, @regex, etc.)
• •Looking for struct validation patterns and best practices

Instructions

1. •

   Clone to a temp directory using shallow clone:

   bash

   git clone --depth 1 https://github.com/tlipoca9/devgen /tmp/devgen
   

2. •

   Analyze locally using file tools:

   • •Read key files in /tmp/devgen/cmd/validategen/:
     • •README.md - Complete documentation (Chinese)
     • •README_EN.md - Complete documentation (English)
     • •generator/generator.go - Main generator logic
     • •generator/rule.go - Rule definitions
     • •generator/registry.go - Rule registry
     • •rules/validategen.md - AI Rules for CodeBuddy/Cursor/Kiro
   • •Use Grep/AST-grep to find specific patterns
3. •

   Reuse existing clones — if /tmp/devgen already exists, don't re-clone

4. •

   Clean up when analysis is complete:

   bash

   rm -rf /tmp/devgen
   

Key Concepts

Annotation Format

// validategen:@validate
type MyStruct struct {
    // validategen:@required
    // validategen:@email
    Field string
}

Validation Rules Overview

Key Annotations

@validate - Mark struct for validation

// validategen:@validate
type User struct {
    Name string
}

@required - Field must be non-zero

// validategen:@required
Name string  // non-empty string
Age int      // > 0
IsActive bool // must be true
Tags []string // non-empty slice
Profile *Profile // non-nil pointer

@oneof_enum - Enum type validation

// enumgen:@enum(string)
type Role int

// validategen:@validate
type User struct {
    // validategen:@oneof_enum(Role)
    Role Role  // auto-uses RoleEnums.Contains()
}

@method - Call custom validation

type Address struct {
    Street string
}

func (a Address) Validate() error { ... }

// validategen:@validate
type User struct {
    // validategen:@method(Validate)
    Address Address
}

postValidate hook

// validategen:@validate
type User struct {
    Role string
    Age int
}

func (x User) postValidate(errs []string) error {
    // Custom validation logic
    return nil
}

Generated Methods

Example Usage

Definition

// validategen:@validate
type User struct {
    // validategen:@required
    // validategen:@gt(0)
    ID int64

    // validategen:@required
    // validategen:@min(2)
    // validategen:@max(50)
    Name string

    // validategen:@required
    // validategen:@email
    Email string

    // validategen:@gte(0)
    // validategen:@lte(150)
    Age int

    // validategen:@oneof(admin, user, guest)
    Role string

    // validategen:@url
    Website string

    // validategen:@method(Validate)
    Address Address
}

Usage

user := &User{
    ID:    1,
    Name:  "John",
    Email: "john@example.com",
    Age:   25,
    Role:  "admin",
}

if err := user.Validate(); err != nil {
    fmt.Println("Validation failed:", err)
}

Key files to reference

• •/tmp/devgen/cmd/validategen/README.md - Full documentation (Chinese)
• •/tmp/devgen/cmd/validategen/README_EN.md - Full documentation (English)
• •/tmp/devgen/cmd/validategen/generator/generator.go - Main generator
• •/tmp/devgen/cmd/validategen/generator/rule.go - Rule definitions
• •/tmp/devgen/cmd/validategen/generator/registry.go - Rule registry
• •/tmp/devgen/cmd/validategen/rules/validategen.md - AI Rules documentation