program

Program

Using Copygen programmatically allows you to implement custom loaders, matchers, and generator functions, or pass .yml files similarly to the command line tool.

Disclaimer

Copygen uses a AGPLv3 License.

An exception is provided for template and example files, which are licensed under the MIT License. While this license lets you use the generator tool without restriction, proprietary programmatic usage of Copygen requires the purchase of a license exception.

You can receive a license exception for Copygen by contacting SwitchUpCB using the Copygen License Exception Inquiry Form.

Standard

The Run() function operates similarly to using copygen -yml path in your command line interface.

Define the Environment

Use an Environment object to specify the .yml Copygen will use.

env := cli.Environment{
    YMLPath: "relative/path/to/yml/",
    Output:  false, // Don't output to standard output.
    Write:   true,  // Write the output to a file.
}

Output

Generate code using Run().

code, err := env.Run()
if err != nil {
    return err
}

fmt.Println(code)

Custom

The Run() function shows the flow of the standard copygen program.

// The configuration file is loaded (.yml)
gen, err := config.LoadYML(e.YMLPath)
if err != nil {
    return "", fmt.Errorf("%w", err)
}

// The data file is parsed (.go)
if err = parser.Parse(gen); err != nil {
    return "", fmt.Errorf("%w", err)
}

// The matcher is run on the parsed data (to create the objects used during generation).
if err = matcher.Match(gen); err != nil {
    return "", fmt.Errorf("%w", err)
}

// The generator is used to generate code.
code, err := generator.Generate(gen, e.Output, e.Write)
if err != nil {
    return "", fmt.Errorf("%w", err)
}

return code, nil

Copygen's standard functions (Parse, Match, Generate) accept a model.Generator. This lets the implementation of any configuration method (including LoadYML) with a Copygen standard function, as long as that method returns a valid model.Generator. similarly, custom Parse, Match, and Generate functions can be used with Copygen standard functions interchangeably.

Configuration

The purpose of the config is to configure the setup, output, and template filepaths of a Generator; along with any GeneratorOptions. For more more information, read the documentation.

Parser

The purpose of the parser is to determine:

1. The code that is kept (Generator.Keep) from the setup file (placed above generated code in the output file).
2. Define the Generator.Functions (which contain fields).

For more information, read the documentation.

Parser Options

Read the documentation.

Matcher

Read the documentation.

Generator

The generator package exports three methods of code generation by default. The easiest way to customize the generator is by using templates.

For more information, read the documentation.

Debug

The debug.go file provides helper functions during debugging. Use a GoAst Viewer to view an Abstract Syntax Tree.

PrintFieldGraph

Parser

type *models.Account
    Unpointed Field "*models.Account" of Definition "" Fields[4]: Parent ""
        Unpointed Field ID "*models.Account.ID" of Definition "int" Fields[0]: Parent "*models.Account"
        Unpointed Field Name "*models.Account.Name" of Definition "string" Fields[0]: Parent "*models.Account"
        Unpointed Field Password "*models.Account.Password" of Definition "string" Fields[0]: Parent "*models.Account"
        Unpointed Field Email "*models.Account.Email" of Definition "string" Fields[0]: Parent "*models.Account"
type *models.User
    Unpointed Field "*models.User" of Definition "" Fields[3]: Parent ""
        Unpointed Field UserID "*models.User.UserID" of Definition "int" Fields[0]: Parent "*models.User"
        Unpointed Field Name "*models.User.Name" of Definition "string" Fields[0]: Parent "*models.User"
        Unpointed Field UserData "*models.User.UserData" of Definition "string" Fields[0]: Parent "*models.User"
type *domain.Account
    Unpointed Field "*domain.Account" of Definition "" Fields[4]: Parent ""
        Unpointed Field ID "*domain.Account.ID" of Definition "int" Fields[0]: Parent "*domain.Account"
        Unpointed Field UserID "*domain.Account.UserID" of Definition "string" Fields[0]: Parent "*domain.Account"
        Unpointed Field Name "*domain.Account.Name" of Definition "string" Fields[0]: Parent "*domain.Account"
        Unpointed Field Other "*domain.Account.Other" of Definition "string" Fields[0]: Parent "*domain.Account"

Matcher

type *models.Account
    Unpointed Field "*models.Account" of Definition "" Fields[2]: Parent ""
        From Field ID "models.Account.ID" of Definition "int" Fields[0]: Parent "*models.Account"
        From Field Name "models.Account.Name" of Definition "string" Fields[0]: Parent "*models.Account"
type *models.User
    Unpointed Field "*models.User" of Definition "" Fields[1]: Parent ""
        From Field UserID "models.User.UserID" of Definition "int" Fields[0]: Parent "*models.User"
type *domain.Account
    Unpointed Field "*domain.Account" of Definition "" Fields[3]: Parent ""
        To Field ID "domain.Account.ID" of Definition "int" Fields[0]: Parent "*domain.Account"
        To Field UserID "domain.Account.UserID" of Definition "string" Fields[0]: Parent "*domain.Account"
        To Field Name "domain.Account.Name" of Definition "string" Fields[0]: Parent "*domain.Account"

Use PrintGeneratorFields to call PrintFunctionFields on all of a generator's functions.

PrintFieldTree

Parser

type Account // domain
    // 0
    ID      int
    Name    string
    Email   string
            // 1
    User    domain.DomainUser
                UserID  int
                Name    string    
type User    // models
    // 0 
    UserID    int
    Name      string
              // 1
    UserData  models.UserData
                  Options map[string]interface{}
                  // 2
                  Data    models.Data
                        ID      int
type Account // models
    // 0
    ID       int
    Name     string
    Password string
    Email    string

Matcher

// depth-level 0 tree
type Account
    ID      int
    Name    string
type User
    UserID  int
type Account
    ID      int
    UserID  int
    Name    string

PrintFieldRelation

To Field ID "*domain.Account.ID" of Definition "int" Fields[0]: Parent "*domain.Account" and From Field ID "models.Account.ID" of Definition "int" Fields[0]: Parent "*models.Account" are related to each other.
To Field ID "*domain.Account.ID" of Definition "int" Fields[0]: Parent "*domain.Account" is not related to From Field Name "models.Account.Name" of Definition "string" Fields[0]: Parent "*models.Account".
To Field ID "*domain.Account.ID" of Definition "int" Fields[0]: Parent "*domain.Account" is not related to From Field Password "models.Account.Password" of Definition "string" Fields[0]: Parent "*models.Account".
To Field ID "*domain.Account.ID" of Definition "int" Fields[0]: Parent "*domain.Account" is not related to From Field Email "models.Account.Email" of Definition "string" Fields[0]: Parent "*models.Account".
...