feat: create xml parser in Kotlin

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/XmlCommentNode.kt

@@ -0,0 +1,9 @@
+package dev.vighnesh153.xml.formatter.ast
+
+import dev.vighnesh153.xml.formatter.lexer.Token
+
+class XmlCommentNode(val comment: Token) : XmlExpression {
+    override fun toString(indentation: Int): String {
+        return "${buildIndentation(indentation)}<!-- ${comment.tokenLiteral.trim()} -->"
+    }
+}

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/XmlElementAttribute.kt

@@ -0,0 +1,13 @@
+package dev.vighnesh153.xml.formatter.ast
+
+import dev.vighnesh153.xml.formatter.lexer.Token
+
+class XmlElementAttribute(
+    val namespaces: List<Token>,
+    val value: Token,
+) {
+    override fun toString(): String {
+        val key = namespaces.joinToString(":") { it.tokenLiteral }
+        return "$key=\"${value.tokenLiteral}\""
+    }
+}

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/XmlExpression.kt

@@ -0,0 +1,5 @@
+package dev.vighnesh153.xml.formatter.ast
+
+sealed interface XmlExpression {
+    fun toString(indentation: Int): String
+}

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/XmlProgram.kt

@@ -0,0 +1,14 @@
+package dev.vighnesh153.xml.formatter.ast
+
+class XmlProgram : XmlExpression {
+    private val mutableStatements = mutableListOf<XmlExpression>()
+    val statements: List<XmlExpression>
+        get() = mutableStatements.toList()
+
+    fun addStatement(stmt: XmlExpression) {
+        mutableStatements.add(stmt)
+    }
+
+    override fun toString(indentation: Int): String =
+        mutableStatements.joinToString("\n") { it.toString(indentation) }
+}

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/XmlPrologNode.kt

@@ -0,0 +1,23 @@
+package dev.vighnesh153.xml.formatter.ast
+
+class XmlPrologNode : XmlExpression {
+    private val mutableAttributes = mutableListOf<XmlElementAttribute>()
+    val attributes: List<XmlElementAttribute>
+        get() = mutableAttributes.toList()
+
+    fun addAttribute(attr: XmlElementAttribute) {
+        mutableAttributes.add(attr)
+    }
+
+    override fun toString(indentation: Int): String {
+        val builder = StringBuilder()
+        builder.append(buildIndentation(indentation))
+        builder.append("<?xml")
+        for (attr in mutableAttributes) {
+            builder.append(" ")
+            builder.append(attr.toString())
+        }
+        builder.append("?>")
+        return builder.toString()
+    }
+}

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/XmlTagNode.kt

@@ -0,0 +1,68 @@
+package dev.vighnesh153.xml.formatter.ast
+
+import dev.vighnesh153.xml.formatter.lexer.Token
+
+class XmlTagNode(
+) : XmlExpression {
+    private val mutableNamespaces = mutableListOf<Token>()
+    val namespaces: List<Token>
+        get() = mutableNamespaces.toList()
+
+    private val mutableAttributes = mutableListOf<XmlElementAttribute>()
+    val attributes: List<XmlElementAttribute>
+        get() = mutableAttributes.toList()
+
+    private val mutableChildren = mutableListOf<XmlExpression>()
+    val children: List<XmlExpression>
+        get() = mutableChildren.toList()
+
+    fun addNamespace(ns: Token) {
+        mutableNamespaces.add(ns)
+    }
+
+    fun addAttribute(attr: XmlElementAttribute) {
+        mutableAttributes.add(attr)
+    }
+
+    fun addChild(child: XmlExpression) {
+        mutableChildren.add(child)
+    }
+
+    override fun toString(indentation: Int): String {
+        val builder = mutableListOf<String>()
+
+        val tag = mutableNamespaces.joinToString(":") { it.tokenLiteral }
+
+        builder.add("${buildIndentation(indentation)}<$tag")
+        if (mutableAttributes.size == 1) {
+            val serializedAttrs = mutableAttributes.joinToString(" ") { it.toString() }
+            builder[builder.lastIndex] += " $serializedAttrs"
+        } else if (mutableAttributes.size > 1) {
+            for (attr in mutableAttributes) {
+                builder.add("${buildIndentation(indentation + 1)}$attr")
+            }
+        }
+
+        if (mutableChildren.isEmpty()) {
+            builder[builder.lastIndex] += " />"
+        } else {
+            builder[builder.lastIndex] += ">"
+        }
+
+        // if only a single text node child
+        if (mutableChildren.size == 1 && mutableChildren.first() is XmlTextNode) {
+            return builder.joinToString("\n") + mutableChildren.first()
+                .toString(0) + "</$tag>"
+        }
+
+        for (child in mutableChildren) {
+            builder.add(child.toString(indentation + 1))
+        }
+
+        if (mutableChildren.isNotEmpty()) {
+            builder.add("${buildIndentation(indentation)}</$tag>")
+        }
+
+        return builder.joinToString("\n")
+    }
+}

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/XmlTextNode.kt

@@ -0,0 +1,9 @@
+package dev.vighnesh153.xml.formatter.ast
+
+import dev.vighnesh153.xml.formatter.lexer.Token
+
+class XmlTextNode(val text: Token) : XmlExpression {
+    override fun toString(indentation: Int): String {
+        return "${buildIndentation(indentation)}${text.tokenLiteral.trim()}"
+    }
+}

jvm-tools/XmlFormatter/src/main/kotlin/dev/vighnesh153/xml/formatter/ast/utils.kt

@@ -0,0 +1,3 @@
+package dev.vighnesh153.xml.formatter.ast
+
+internal fun buildIndentation(indentation: Int): String = " ".repeat(indentation * 4)