BIFs

Create custom Built-In Functions (BIFs) in BoxLang or Java for your module

BIFs are custom functions that extend BoxLang's built-in function library. Create them in pure BoxLang or Java.

🟦 BoxLang BIFs

Place .bx files in your module's bifs/ folder. They are auto-discovered and compiled at runtime.

File: bifs/Greet.bx

/**
 * Returns a greeting message
 *
 * @param name The name to greet (required)
 * @param greeting The greeting prefix (default: "Hello")
 *
 * @return The formatted greeting string
 */
function invoke(
    required string name,
    string greeting = "Hello"
) {
    return "#greeting#, #name#!"
}

Usage from BoxLang:

result = greet( "World" )
// → "Hello, World!"

result = greet( name = "World", greeting = "Hi" )
// → "Hi, World!"

Features:

• ✅ No compilation — just create the file
• ✅ Auto-discovered by folder scanning
• ✅ Supports @BoxMember annotation for member methods
• ✅ Full access to BoxLang runtime via injected services

☕ Java BIFs

Member Functions

Register BIFs as member methods on BoxLang types:

BoxLang

/**
 * @BoxMember string
 */
function shout( required string text ) {
    return text.ucase() & "!!!"
}

Usage: "hello".shout() → "HELLO!!!"

Java

When to Use Which

Criteria	BoxLang BIFs	Java BIFs
Complexity	Simple logic	Complex algorithms
Performance	Good for most cases	Critical paths
Dependencies	None or minimal	External JARs
Development speed	Fast iteration	Requires rebuild
Team skills	BoxLang developers	Java developers

Next Steps

• Components — Create custom BoxLang tags
• Interceptors — Listen to runtime events
• Services — Global runtime services (Java only)