Grule

Grule is Kotlin multiplatform library as a general-purpose parser.

NOTE: grule is experimental yet.

Sample - Json parser

classJsonRegMatcherTest : Grammar() {
val string by lexer { X/"""(".*?")""" }
val number by lexer { X/"\\d+(\\.\\d+)?" }
val bool by lexer { X/"true|false" }
val nil by lexer { X/"null" }
init {
lexer.token { X-"{}[]:," }
lexer.skip { SPACEorWRAP }
}
val jObject:Parser by parser { jString or jNumber or jBool or jNil or jArray or jDict }
val jString by parser { X+ string }
val jNumber by parser { X+ number }
val jBool by parser { X+ bool }
val jNil by parser { X+ nil }
val jArray by parser { X+"["+ jObject.join(X+",") +"]" }
val jPair by parser { X+ jString +":"+ jObject }
val jDict by parser { X+"{"+ jPair.join(X+",") +"}" }
@Test
funjson() {
val source ="""{ "a": [1, 2.34], "b": "hello" }"""println(source)
println("-----------------")
val astNode = jObject.parse(tokenStream(source))
println(astNode.toStringTree())
}
}

Output

{ "a": [1, 2.34], "b": "hello" }
-----------------
jObject/jDict
├─ {
├─ jPair
│ ├─ jString/string("a")
│ ├─ :
│ └─ jObject/jArray
│ ├─ [
│ ├─ jObject/jNumber/number(1)
│ ├─ ,
│ ├─ jObject/jNumber/number(2.34)
│ └─ ]
├─ ,
├─ jPair
│ ├─ jString/string("b")
│ ├─ :
│ └─ jObject/jString/string("hello")
└─ }

Setting up the dependency

Add it in your root build.gradle at the end of repositories:

allprojects {
repositories {
maven("https://jitpack.io")
}
}

dependencies {
implementation("com.github.7hens.grule:grule:0.2")
}