SlowXml: A Pure Kotlin Xml Parser

life is short, may time slow down

Installation

1. create a file named gpr.properties in your project root, filling with:

   gpr.user="your username"
   gpr.key="your token"

   make sure you've added gpr.properties in .gitignore file !!!!

2. add gpr to your repositories section

   maven {
       url = uri("https://maven.pkg.github.com/whiterasbk/slowxml")
       credentials {
           username = project.findProperty("gpr.user") as String? ?: System.getenv("USERNAME")
           password = project.findProperty("gpr.key") as String? ?: System.getenv("GITHUB_TOKEN")
       }
   }

   alternatively, jitpack is available within a few certain versions

   repositories {
       maven { url = uri("https://jitpack.io") }
   }

   while using jitpack, you don't need a gpr.properties file, but latest version has to be only 0.2

3. add slowxml to your dependencies section

   dependencies {
       implementation("com.github.whiterasbk:slowxml-$platform:$latest_version")
       // where platform be like: js, jvm
       // version may check in latest release
   }

4. sync build.gradle.kts

How to use

use parseXml function by passing xml string, it will return a XmlNode object representing the xml string

here's a simple sample:

val node = parseXml("<root attr=\"value\"> 123 </root>")

and you will be able to access its attributes through node.attrbutes, text content through node.content

also, if you prefer diving into it, loopInXmlString brings more flexibility:

var get = ""
loopInXmlString("<r> <!-- comment --> </a>") {     
    onComment { get = it }
}

by calling onComment function, loopInXmlString will automate invoke the given lambda

as the inside pointer meet comment, get will be set to comment, then you can dill with it

the following is supported hooks:

• onOpenTag
• onCloseTag
• onEndDefineAttributes
• onAttributeName
• onAttributeValue
• onComment
• onTextContent

How does it work

slowxml uses state machine to parse xml string into objects

this state machine will change its state according to current pinter and state, which make the computer knows what the stage is it now

the state 11 switch to 1 happens only when meet close tag, no matter self close tag or not, base on this judgement, we can start our procession

when {
    //    ...
    previousState == 11 and currentState == 1 -> {
        // meet close tag, create a new node
    }
    //    ...
}

other situations can also be analyzed from below

digraph G {
   node [shape = circle];
   start [shape=Mdiamond]
   
   start -> 1
   1 -> 1 [label = "  blank"]
   1 -> 2 [label = "  <"]
   2 -> 2 [label = "  blank"]
   2 -> 3 [label = "  valid"]
   2 -> 13 [label = "  /", color=blue1]
   3 -> 3 [label = "  valid"]
   3 -> 4 [label = "  blank"]
   3 -> 11 [label = "  /"]
   3 -> 12 [label = ">"]
   4 -> 4 [label = "  blank"]
   4 -> 5 [label = "  valid"]
   4 -> 11 [label = "  /"]
   4 -> 12 [label = "  >"]
   5 -> 5 [label = "  valid"]
   5 -> 6 [label = "  blank"]
   5 -> 7 [label = "  ="]
   6 -> 6 [label = "  blank"]
   6 -> 7 [label = "  ="]
   7 -> 7 [label = "  blank"]
   7 -> 8 [label = "  qoute"]
   8 -> 4 [label = qoute]
   8 -> 9 [label = "  expect qoute"]
   9 -> 4 [label = "  qoute"]
   9 -> 9 [label = "  except qoute"]
   10 -> 1 [label = "  >"]
   10 -> 10 [label = "  blank"]
   11 -> 1 [label = "  >", color = brown1]
   12 -> 2 [label = "  <"]
   12 -> 12 [label = "  blank"]
   12 -> 15 [label = "  except (blank) and <>"]
   13 -> 13 [label = "  blank"]
   13 -> 14 [label = "  valid"]
   14 -> 1 [label = "  >"]
   14 -> 14 [label = "  valid"]
   14 -> 10 [label = "  blank"]
   15 -> 2 [label = "  <"]
   15 -> 15 [label = "  except (blank) and <>"]
}

link to GraphvizOnline to fully and lively access its code