Export Functions

Guide to export functions from your plugin to be used by other language modules within Plugify.

In the Plugify ecosystem, Go plugins can export functions to make them accessible to other plugins. This guide explains how to define and export functions in Go and provides examples to help you integrate your plugins seamlessly.

Basic Type Mapping

The following table lists how types are exposed to the JavaScript API:

C++ Type	Go Type	Plugify Alias	Ref Support ?
void	void (not used in Go)	void	❌
bool	bool	bool	✅
char	byte	char8	✅
char16_t	rune	char16	✅
int8_t	int8	int8	✅
int16_t	int16	int16	✅
int32_t	int32	int32	✅
int64_t	int64	int64	✅
uint8_t	uint8	uint8	✅
uint16_t	uint16	uint16	✅
uint32_t	uint32	uint32	✅
uint64_t	uint64	uint64	✅
uintptr_t	uintptr	ptr64	✅
uintptr_t	uintptr	ptr32	✅
float	float32	float	✅
double	float64	double	✅
void*	unsafe.Pointer	function	❌
plg::string	string	string	✅
plg::any	any	any	✅
plg::vector<bool>	bool	bool	✅
plg::vector<char>	byte	char8	✅
plg::vector<char16_t>	rune	char16	✅
plg::vector<int8_t>	int8	int8	✅
plg::vector<int16_t>	int16	int16	✅
plg::vector<int32_t>	int32	int32	✅
plg::vector<int64_t>	int64	int64	✅
plg::vector<uint8_t>	uint8	uint8	✅
plg::vector<uint16_t>	uint16	uint16	✅
plg::vector<uint32_t>	uint32	uint32	✅
plg::vector<uint64_t>	uint64	uint64	✅
plg::vector<uintptr_t>	uintptr	ptr64	✅
plg::vector<uintptr_t>	uintptr	ptr32	✅
plg::vector<float>	float32	float	✅
plg::vector<double>	float64	double	✅
plg::vector<plg::string>	string	string	✅
plg::vector<plg::any>	any	any	✅
plg::vector<plg::vec2>	Vector2	vec2	✅
plg::vector<plg::vec3>	Vector3	vec3	✅
plg::vector<plg::vec4>	Vector4	vec4	✅
plg::vector<plg::mat4x4>	Matrix4x4	mat4x4	✅
plg::vec2	Vector2	vec2	✅
plg::vec3	Vector3	vec3	✅
plg::vec4	Vector4	vec4	✅
plg::mat4x4	Matrix4x4	mat4x4	✅

Exporting Functions in Go

Exporting functions in Go requires marking the functions for export using the //export directive. These functions can then be called by other plugins. Plugify's Go Language Module handles the rest.

Using Generator to Simplify Function Export

The generator.go tool simplifies the process of exporting Go functions by:

Scanning the Plugin Folder: It scans your plugin's root folder to identify functions to export.
Reading the Manifest: It reads the .pplugin manifest file to understand the function signatures and types.
Generating Files: It generates autoexport.go and autoexport.h files with the necessary code to export functions.

This tool eliminates the need for manual marshalling, making it easier for developers to integrate their Go plugins into the Plugify ecosystem.

Basic Example

Here’s a simple example of exporting a function in a Go plugin:

Function Definition

plugin.go

package main

import "C"

func AddNumbers(a int32, b int32) int32 {
    /**
     * Adds two integers.
     *
     * @param a: First integer.
     * @param b: Second integer.
     * @return: Sum of a and b.
     */
    return a + b
}

func main() {} // Required for Go plugins

Plugin Manifest

To export the function, describe it in the plugin manifest under the exportedMethods section:

plugin_name.pplugin

{
  "name": "ExampleGoPlugin",
  "version": "1.0.0",
  "exportedMethods": [
    {
      "name": "AddNumbers",
      "funcName": "__AddNumbers",
      "paramTypes": [
        {
          "type": "int32",
          "name": "a"
        },
        {
          "type": "int32",
          "name": "b"
        }
      ],
      "retType": {
        "type": "int32"
      }
    }
  ]
}

Generated Code

Run the generator.go tool to generate the autoexport.go and autoexport.h files. These files will handle the marshalling of Plugify types to Go types.

autoexport.go

package main

// #include "autoexports.h"
import "C"
import (
    "github.com/untrustedmodders/go-plugify"
    "reflect"
    "unsafe"
)

//export __AddNumbers
func __AddNumbers(a int32, b int32) int32 {
    return AddNumbers(a, b)
}

This generated code handles the conversion of Plugify types to Go types and ensures the function can be called from other plugins.

Advanced Example: Exporting Complex Functions

Here’s an example of exporting a function with complex parameter and return types:

Function Definition

plugin.go

package main

import "C"
import "unsafe"

func ProcessData(data []float64, prefix string) []string {
    /**
     * Processes an array of doubles and returns a formatted string.
     *
     * @param data: Array of double values.
     * @param length: Length of the array.
     * @param prefix: Prefix to add to each value.
     * @return: Formatted string.
     */
    result := ""
    for _, value := range data {
        result += fmt.Sprintf("%s%f", prefix, value)
    }

    return result
}

Plugin Manifest

plugin_name.pplugin

{
  "name": "ExampleGoPlugin",
  "version": "1.0.0",
  "exportedMethods": [
    {
      "name": "ProcessData",
      "funcName": "__ProcessData",
      "paramTypes": [
        {
          "type": "double[]",
          "name": "data"
        },
        {
          "type": "string",
          "name": "prefix"
        }
      ],
      "retType": {
        "type": "string"
      }
    }
  ]
}

Generated Code

Run the generator.go tool to generate the autoexport.go and autoexport.h files. These files will handle the marshalling of Plugify types to Go types.

autoexport.go

package main

// #include "autoexports.h"
import "C"
import (
    "github.com/untrustedmodders/go-plugify"
    "reflect"
    "unsafe"
)

//export __ProcessData
func __ProcessData(data *C.PlgVector, prefix *C.PlgString) C.PlgString {
    __result := ProcessData(plugify.GetVectorDataDouble((*plugify.PlgVector)(unsafe.Pointer(data))), plugify.GetStringData((*plugify.PlgString)(unsafe.Pointer(prefix))))
    __return := plugify.ConstructString(__result)
    return *(*C.String)(unsafe.Pointer(&__return))
}

This generated code handles the conversion of Plugify types to Go types and ensures the function can be called from other plugins.

Handling Callbacks

Plugify allows you to export functions that accept callbacks as parameters. Here’s an example:

Function Definition

plugin.go

package main

import "C"

func ExecuteWithCallback(value int32, inputStr string, callback PlugifyCallback) {
    /**
     * Executes a callback function with the provided parameters.
     *
     * @param value: Integer value.
     * @param inputStr: Input string.
     * @param callback: Callback function to execute.
     */
    result := callback(value, inputStr)
    fmt.Printf("Callback result: %s\n", result)
}

Plugin Manifest

plugin_name.pplugin

{
  "name": "ExampleGoPlugin",
  "version": "1.0.0",
  "exportedMethods": [
    {
      "name": "ExecuteWithCallback",
      "funcName": "__ExecuteWithCallback",
      "paramTypes": [
        {
          "type": "int32",
          "name": "value"
        },
        {
          "type": "string",
          "name": "inputStr"
        },
        {
          "type": "function",
          "name": "callback",
          "prototype": {
            "name": "ExampleCallback",
            "funcName": "__ExampleCallback",
            "paramTypes": [
              {
                "type": "int32",
                "name": "value"
              },
              {
                "type": "string",
                "name": "inputStr"
              }
            ],
            "retType": {
              "type": "string"
            }
          }
        }
      ],
      "retType": {
        "type": "void"
      }
    }
  ]
}

Generated Code

Run the generator.go tool to generate the autoexport.go and autoexport.h files. These files will handle the marshalling of Plugify types to Go types.

autoexport.go

package main

// #include "autoexports.h"
import "C"
import (
    "github.com/untrustedmodders/go-plugify"
    "reflect"
    "unsafe"
)

//export __ExecuteWithCallback
func __ExecuteWithCallback(value int32, inputStr *C.PlgString, callback unsafe.Pointer) {
    ExecuteWithCallback(value, plugify.GetStringData((*plugify.PlgString)(unsafe.Pointer(inputStr))), plugify.GetDelegateForFunctionPointer(callback, reflect.TypeOf(PlugifyCallback(nil))).(PlugifyCallback))
}

This generated code handles the conversion of Plugify types to Go types and ensures the function can be called from other plugins.

Best Practices

Use //export: Always use the //export directive to mark functions for export.
Follow Type Conventions: Adhere to Plugify's type conventions for parameters and return values.
Document Your Functions: Clearly document the purpose, parameters, and return values of exported functions.
Test Thoroughly: Test your exported functions to ensure they work as expected when called by other plugins.
Update the Manifest: Always describe exported functions in the plugin manifest under the exportedMethods section.

Conclusion

Exporting functions in Go plugins is straightforward when you follow Plugify's conventions and best practices. By using the //export directive, adhering to type conventions, and describing functions in the plugin manifest, you can create robust and interoperable plugins. For more advanced use cases, such as handling callbacks, use the techniques outlined in this guide.

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