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This repository is hosted on bintray, which will shut down on May 1st, 2021. After that date this library will no longer be directly available.

You may still fork or download this repository for your own use.

KotlinBard

KotlinBard is a collection of extension functions for KotlinPoet to provide a fluent kotlin DSL for kotlin code generation.

Example

KotlinPoet's first example is generated with the following:

val file = buildFile("", "HelloWorld") {
    val greeterClass = ClassName("", "Greeter")
    addClass(greeterClass) {
        primaryConstructor {
            addParameter("name", String::class)
        }
        addProperty("name", String::class) {
            initializer("name")
        }
        addFunction("greet") {
            addStatement("println(%P)", "Hello, \$name")
        }
    }

    addFunction("main") {
        addParameter("args", String::class, VARARG)
        addStatement("%T(args[0]).greet()", greeterClass)
    }
}
file.writeTo(System.out)

Fun fact: to cover all of KotlinPoet's functions, KotlinBard uses code generation to generate many extension functions -- it uses a previous version of itself to generate itself!

Features

buildXXX {} and addXXX {} functions for every builder

val file = buildFile {
    addClass(...){ ... }
    addInterface(...){ ... } //Each variant of TypeSpec and FunSpec have separate functions
    addTypeAlias(...){ ... }
}
val annotation = buildAnnotation(...){ ... } //AnnotationSpec
val annotationType = buildAnnotationClass(...){ ... } //TypeSpec that is an annotation class

//Each type of Spec has its own function
val enum = buildEnum(...){ ... }
val intf = buildInterface(...){ ... }
val constructor = buildContructor {}
val getter = buildGetter {}

modify extensions for every Spec, corresponding to converting to a builder then applying actions

val newClass = klass.modify(name = newName) { ... }

CodeBlock creation functions

val aBlock = codeBlock("println(%S)", "Hello, weird world")
//or, for a more inline syntax:
val aBlock = "println(%S)".codeFmt("Hello, weird world")

Builders are marked with DslMarker

val file = buildFile("", "File") {
    addImport(String::class)
    addClass("Foo") {
        addImport(Int::class) //compile error
    }
}

Extensions and DSLs for control flow

val function = buildFunction("analyzeTaco") {
    addCode { //functions are defined in the CodeBlockBuilder scope
        controlFlow("taco.let") {
            addStatement("println(it)")
        }
        `if`("taco.isSpicy()") {
            addStatement("println(%S)", "spicy!!")
        }.`else if`("me.isHungry") {
            addStatement("eat(taco)")
        } `else` {
            addStatement("saveForLater(taco)")
        }

        `do` {
            addStatement("makeTaco()")
        }.`while`("tacos < 5")

        `for`("taco in tacos") {
            addStatement("println(%P)", "taco information: \$taco")
        }

        `when`("taco") {
            "is SpicyTaco" - {
                addStatement("println(%S)", "Spicy!!")
            }
            "else" - "eat(%L)".codeFmt("taco")
        }
    }
}

This generates the following:

fun analyzeTaco() {
    taco.let {
        println(it)
    }
    if (taco.isSpicy()) {
        println("spicy!!")
    } else if (me.isHungry) {
        eat(taco)
    } else {
        saveForLater(taco)
    }
    do {
        makeTaco()
    } while (tacos < 5)
    for (taco in tacos) {
        println("""taco information: $taco""")
    }
    when (taco) {
        is SpicyTaco -> {
            println("Spicy!!")
        }
        else -> eat(taco)
    }
}

Quick property setter with parameter

val mySetter = buildSetter("value") {
    addStatement("field = value")
}

val prop = buildProperty("prop", String::class) {
    mutable()
    setter("value") {
        addStatement("println(%S)", "setting!")
        addStatement("field = value")
    }
}

Extensions for TypeNames

val myTypeVarName = TypeVariableName("T")
    .reified
    .plusTag(ATag::class, myTag)
val myTypeDecName = Int::class.asTypeName()
    .plusAnnotations(annotationSpec)

Usage

With gradle:

repositories {
    jcenter()
}

dependencies {
    implementation("io.github.enjoydambience:kotlinbard:0.4.0")
}