Initial commit

.gitignore

+.gradle
+.idea
+build
\ No newline at end of file

.gitlab-ci.yml

+image: java:8-jdk
+
+stages:
+  - build
+  - test
+  - deploy
+
+before_script:
+  - export GRADLE_USER_HOME=`pwd`/.gradle
+  - chmod u+x ./gradlew
+
+cache:
+  paths:
+    - .gradle/wrapper
+    - .gradle/caches
+
+build:
+  stage: build
+  script:
+    - ./gradlew assemble
+  only:
+    - master
+
+test:
+  stage: test
+  script:
+    - ./gradlew check
+
+deploy:
+  script:
+    - ./gradlew publish
+  only:
+    - master
\ No newline at end of file

LICENSE

+MIT License
+
+Copyright (c) 2020-2021 Tim Kluge
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

+jackrat
+============================
+
+This library allows to construct backtracking top down packrat parsers in Kotlin using parser combination. Packrat parsing enables the parsing of PEG Grammars in linear time. Parsers are combinated using the following basic parsers:
+
+- `AtomParser`: Matches only a specified UTF8 string
+- `RegexParser`: Matches a regular expression
+- `AndParser`: Matches a given list of parsers sequentially
+- `OrParser`: Matches if any of a given list of parsers matches
+- `KleeneParser`: Matches a parser 0 to `n` times, optionally separated by another parser
+- `ManyParser`: Matches a parser 1 to `n` times, optionally separated by another parser
+- `MaybeParser`: Matches a parser 0 or 1 times
+- `EmptyParser`: Does not read any input and matches in every case
+- `EndParser`: Matches only if the scanner has reached the end of the input string 
+
+By default, `Atom` and `Regex` parsers skip (but do not match on) leading whitespace. This can be configured per parser.
+
+If a parser matches, it returns a syntax tree `Node`. Every node points to the parser that produced it, the matched text, and a list of child nodes. Callbacks are not provided atm, so a full syntax tree traversal is needed to process the parse results.
+
+To construct recursive parsers, create parser combinators with `nil` as the sub parser. After creating the sub parser that itself uses the parent parser, use the `Set` function on the parent parser to update its children. The [JSON parser](./json_test.go) provides an example for this.
+
+This library is currently used in production, but some rarely used features may be broken. Additional documentation is ToDo.
+
+Example
+-----------
+
+A full example in form of a working json parser is provided in [JsonTests.kt](https://git-st.inf.tu-dresden.de/timklge/jackrat/-/blob/master/src/commonTest/kotlin/JsonTests.kt).
+
+```kotlin
+val input = "Hello world"
+val scanner = Scanner(input)
+val helloParser = AtomParser("Hello", false)
+val worldParser = AtomParser("world", false)
+val helloAndWorldParser = AndParser(helloParser, worldParser)
+val node = helloAndWorldParser.parse(scanner)
+
+// node is the syntax tree root node
+// node.children is a list containing a node for both the Hello and World parser
+```
+
+Use case
+-----------
+Using this library, you can dynamically define and parse PEG grammars at runtime. Parsing time is proportional to the input length and grammar complexity. Note that if you do not need to build grammars at runtime, consider using a standard LR parser generator.
+
+Left recursion
+-----------
+Left recursion is supported via the method proposed by [Warth et al. (2008)](https://doi.org/10.1145/1328408.1328424).
+
+License
+------------
+Licensed with MIT License. See [LICENSE](../../../LICENSE).
\ No newline at end of file

build.gradle

+plugins {
+    id 'org.jetbrains.kotlin.multiplatform' version '1.4.32'
+    id 'java'
+    id 'maven-publish'
+}
+
+group 'de.timklge'
+version '1.0'
+
+repositories {
+    mavenCentral()
+}
+
+kotlin {
+    jvm()
+    /* js {
+        nodejs()
+    } */
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation kotlin('stdlib-common')
+            }
+        }
+        commonTest {
+            dependencies {
+                implementation kotlin('test-common')
+                implementation kotlin('test-annotations-common')
+            }
+        }
+        jvmTest {
+            dependencies {
+                implementation(kotlin("test-junit"))
+                implementation("junit:junit:4.12")
+            }
+        }
+        /* jsTest {
+            dependencies {
+                implementation(kotlin("test-js"))
+            }
+        } */
+    }
+}
+
+publishing {
+    publications {
+        library(MavenPublication) {
+            from components.java
+        }
+    }
+    repositories {
+        maven {
+            url "https://git-st.inf.tu-dresden.de/api/v4/projects/963/packages/maven"
+            name "GitLab"
+            credentials(HttpHeaderCredentials) {
+                name = 'Job-Token'
+                value = System.getenv("CI_JOB_TOKEN")
+            }
+            authentication {
+                header(HttpHeaderAuthentication)
+            }
+        }
+    }
+}
\ No newline at end of file

gradle.properties

+kotlin.code.style=official
\ No newline at end of file

gradle/wrapper/gradle-wrapper.properties

+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

gradlew.bat

+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

+rootProject.name = 'jackrat'
+

src/commonMain/kotlin/de/timklge/jackrat/And.kt

+package de.timklge.jackrat
+
+import jackrat.de.timklge.jackrat.Scanner
+
+class AndParser(children: List<Parser>, nodeFunc: NodeTransform = ::emptyNodeTransform) : ParserWithChildren(children, nodeFunc) {
+    override val typeName: String = "AndParser"
+
+    override fun Match(s: Scanner): Node? {
+        val startPosition = s.position
+        val nodes = children.map<Parser, Node> {
+            val node = s.applyRule(it)
+            if(node == null){
+                s.position = startPosition
+                return null
+            }
+            node
+        }
+
+        val builder = StringBuilder()
+        nodes.forEach { builder.append(it.matched) }
+        val matched = builder.toString()
+
+        return Node(matched, this, nodes)
+    }
+}
+
+class OrParser(children: List<Parser>, nodeFunc: NodeTransform = ::emptyNodeTransform): ParserWithChildren(children, nodeFunc) {
+    override val typeName: String = "OrParser"
+
+    override fun Match(s: Scanner): Node? {
+        val startPosition = s.position
+        children.forEach {
+            val node = s.applyRule(it)
+            if(node != null){
+                return Node(node.matched, this, listOf(node))
+            }
+            s.position = startPosition
+        }
+        return null
+    }
+}
\ No newline at end of file

src/commonMain/kotlin/de/timklge/jackrat/Atom.kt

+package de.timklge.jackrat
+
+class AtomParser(atom: String, caseInsensitive: Boolean = false, skipWs: Boolean = true, nodeFunc: NodeTransform = ::emptyNodeTransform)
+    : RegexParser(Regex.escape(atom), caseInsensitive, skipWs, nodeFunc){
+    override val typeName: String = "AtomParser"
+}
\ No newline at end of file

src/commonMain/kotlin/de/timklge/jackrat/Empty.kt

+package de.timklge.jackrat
+
+import jackrat.de.timklge.jackrat.Scanner
+
+class EmptyParser(transform: NodeTransform = ::emptyNodeTransform) : Parser(transform) {
+    override val typeName: String = "EmptyParser"
+
+    override fun Match(s: Scanner): Node? {
+        return Node("", this, listOf())
+    }
+}
+
+class EndParser(val skipWhitespace: Boolean = true) : Parser() {
+    override val typeName: String = "EndParser"
+
+    override fun Match(s: Scanner): Node? {
+        val startPosition = s.position
+        if(skipWhitespace){
+            s.skipWhitespace()
+        }
+
+        if(s.position == s.input.length){
+            return Node("", this, listOf())
+        }
+
+        s.position = startPosition
+        return null
+    }
+}
\ No newline at end of file

src/commonMain/kotlin/de/timklge/jackrat/Kleene.kt

+package de.timklge.jackrat
+
+import jackrat.de.timklge.jackrat.Scanner
+
+class KleeneParser(var subParser: Parser, var sepParser: Parser? = null, nodeTransform: NodeTransform = ::emptyNodeTransform) : ParserWithChildren(emptyList(), nodeTransform) {
+    override val typeName: String = "KleeneParser"
+
+    init {
+        children = if(sepParser != null) {
+            listOf(subParser, sepParser!!)
+        } else {
+            listOf(subParser)
+        }
+    }
+
+    override fun Match(s: Scanner): Node? {
+        val nodes = mutableListOf<Node>()
+        var i = 0
+        var lastValidPosition = s.position
+
+        while(true){
+            var matchedsep = false
+            var sepnode: Node? = null
+            if(i > 0 && sepParser != null){
+                sepnode = s.applyRule(sepParser!!) ?: break
+                matchedsep = true
+            }
+            i++
+
+            val node = s.applyRule(subParser) ?: break
+            if(matchedsep) nodes.add(sepnode!!)
+            nodes.add(node)
+            lastValidPosition = s.position
+        }
+        s.position = lastValidPosition
+
+        val builder = StringBuilder()
+        nodes.forEach { builder.append(it.matched) }
+        val matched = builder.toString()
+
+        return Node(matched, this, nodes)
+    }
+}
\ No newline at end of file

src/commonMain/kotlin/de/timklge/jackrat/Many.kt

+package de.timklge.jackrat
+
+import jackrat.de.timklge.jackrat.Scanner
+
+class ManyParser(var subParser: Parser?, var sepParser: Parser? = null, nodeTransform: NodeTransform = ::emptyNodeTransform) : ParserWithChildren(emptyList(), nodeTransform) {
+    override val typeName: String = "ManyParser"
+
+    init {
+        children = if(subParser != null && sepParser != null) {
+            listOf(subParser!!, sepParser!!)
+        } else if(subParser != null){
+            listOf(subParser!!)
+        } else {
+            emptyList()
+        }
+    }
+
+    override fun Match(s: Scanner): Node? {
+        var i = 0
+        var lastValidPos = s.position
+        var nodes = mutableListOf<Node>()
+
+        while(true){
+            var matchedsep = false
+            var sepnode: Node? = null
+
+            if(i > 0 && sepParser != null){
+                sepnode = s.applyRule(sepParser!!)
+                if(sepnode == null) break
+                matchedsep = true
+            }
+            i++
+
+            val node = s.applyRule(subParser!!) ?: break
+            if(matchedsep) nodes.add(sepnode!!)
+
+            nodes.add(node)
+            lastValidPos = s.position
+        }
+        s.position = lastValidPos
+
+        if(nodes.count() >= 1){
+            val builder = StringBuilder()
+            nodes.forEach { builder.append(it.matched) }
+            val matched = builder.toString()
+            return Node(matched, this, nodes)
+        }
+
+        return null
+    }
+}
\ No newline at end of file

src/commonMain/kotlin/de/timklge/jackrat/Maybe.kt

+package de.timklge.jackrat
+
+import jackrat.de.timklge.jackrat.Scanner
+
+class MaybeParser(var subParser: Parser, nodeTransform: NodeTransform = ::emptyNodeTransform) : ParserWithChildren(listOf(subParser), nodeTransform) {
+    override val typeName: String = "MaybeParser"
+
+    override fun Match(s: Scanner): Node? {
+        val startPosition = s.position
+        val node = s.applyRule(subParser)
+        if(node == null){
+            s.position = startPosition
+            return Node("", this, listOf())
+        }
+        return Node(node.matched, this, listOf(node))
+    }
+}
\ No newline at end of file

src/commonMain/kotlin/de/timklge/jackrat/Node.kt

+package de.timklge.jackrat
+
+typealias NodeTransform = (node: Node) -> Node
+
+fun emptyNodeTransform(node: Node) = node
+
+open class Node(val matched: String, val parser: Parser, val children: List<Node>) {
+    var parent: Node? = null
+
+    fun findParser(p: Parser, skipParser: Parser? = null): Node? {
+        return if(parser == p) this else findChildParser(p, skipParser)
+    }
+
+    fun findChildParser(p: Parser, skipParser: Parser? = null): Node? {
+        children.forEach { child ->
+            if(child.parser != skipParser) {
+                val sub = child.findParser(p)
+                if (sub != null) return sub
+            }
+        }
+        return null
+    }
+
+    fun findParsers(vararg ps: Parser): List<Node> {
+        return if(ps.contains(parser)) listOf(this) else findChildParsers(*ps)
+    }
+
+    fun findChildParsers(vararg ps: Parser): List<Node> {
+        val result = mutableListOf<Node>()
+        children.forEach { child ->
+            val subs = child.findParsers(*ps)
+            result.addAll(subs)
+        }
+        return result
+    }
+
+    fun containsParser(p: Parser): Boolean = findParser(p) != null
+
+    fun findParserType(typeName: String): Node? {
+        return if(parser.typeName == typeName) this else findChildParserType(typeName)
+    }
+
+    fun findChildParserType(typeName: String): Node? {
+        children.forEach { child ->
+            val sub = child.findParserType(typeName)
+            if(sub != null) return sub
+        }
+        return null
+    }
+
+    internal fun mapTransforms(): Node {
+        val node = Node(matched, parser, children.map { n ->
+            n.parent = this
+            val node = n.parser.nodeTransform(n)
+            node.parent = this
+            node
+        })
+        return parser.nodeTransform(node)
+    }
+}
\ No newline at end of file

src/commonMain/kotlin/de/timklge/jackrat/Parser.kt

+package de.timklge.jackrat
+
+import jackrat.de.timklge.jackrat.Scanner
+
+data class ParserError(val parser: Parser, val line: Int, val column: Int, val position: Int, val failedParsers: List<Parser>?, val input: String) :
+    Error() {
+
+    override fun toString(): String {
+        val startPos = if(position - 1 >= 0) position - 1 else 0
+        val endPos = if(position + 10 < input.length) input.length - 1 else {
+            if(input.length-1 >= 0) input.length - 1 else 0
+        }
+
+        return "Parser failed at line $line, column $column (position $position of input string) near ${input.slice(startPos..endPos)}"
+    }
+}
+
+abstract class Parser(val nodeTransform: NodeTransform = ::emptyNodeTransform) {
+    abstract val typeName: String
+
+    abstract fun Match(s: Scanner): Node?
+
+    fun parsePartial(originalScanner: Scanner): Node? {
+        return originalScanner.applyRule(this)?.mapTransforms()
+    }
+
+    fun parse(originalScanner: Scanner): Node {
+        val node = originalScanner.applyRule(this)?.mapTransforms()
+        if(node != null){
+            if(originalScanner.position < originalScanner.input.length){
+                val consumed = originalScanner.input.substring(originalScanner.position)
+                val line = consumed.count { it == '\n' } + 1
+                val column = originalScanner.position - consumed.lastIndexOf('\n') + 1
+                throw ParserError(this, line, column, originalScanner.position, null, originalScanner.input)
+            }
+            return node
+        }
+
+        var maxPos = 0
+        val failedParsers: MutableList<Parser> = mutableListOf()
+        for(index in originalScanner.input.length downTo 0){
+            if(!originalScanner.memoization.containsKey(index) || originalScanner.memoization[index]!!.isEmpty()) continue
+            maxPos = index
+            failedParsers += originalScanner.memoization[index]!!.keys
+            if(failedParsers.isNotEmpty()) break
+        }
+        if(maxPos >= originalScanner.input.length) maxPos = originalScanner.input.length - 1
+
+        val consumed = originalScanner.input.substring(0..maxPos)
+        val line = consumed.count { it == '\n'} + 1
+        val lastBreak = if(consumed.lastIndexOf('\n') >= 0) consumed.lastIndexOf('\n') else 0
+        val column = maxPos - lastBreak + 1
+
+        throw ParserError(this, line, column, maxPos, failedParsers, originalScanner.input)
+    }
+}
+
+abstract class ParserWithChildren(var children: List<Parser>, nodeFunc: NodeTransform = ::emptyNodeTransform) : Parser(nodeFunc){
+
+}
+

src/commonMain/kotlin/de/timklge/jackrat/RegexParser.kt

+package de.timklge.jackrat
+
+import jackrat.de.timklge.jackrat.Scanner
+
+open class RegexParser(rs: String, caseInsensitive: Boolean = false, val skipWhitespace: Boolean = true, nodeTransform: NodeTransform = ::emptyNodeTransform) : Parser(nodeTransform) {
+    override val typeName: String = "RegexParser"
+
+    val regex = if(caseInsensitive) Regex("^$rs", RegexOption.IGNORE_CASE) else Regex("^$rs")
+
+    override fun Match(s: Scanner): Node? {
+        val startPosition = s.position
+        if (skipWhitespace) {
+            s.skipWhitespace()
+            if (!s.isAtBreak()) {
+                s.position = startPosition
+                return null
+            }
+        }
+
+        val matched = s.match(regex)
+        if (matched == null) {
+            s.position = startPosition
+            return null
+        }
+
+        if (skipWhitespace) {
+            if (!s.isAtBreak()) {
+                s.position = startPosition
+                return null
+            }
+        }
+
+        return Node(matched, this, listOf())
+    }
+}
\ No newline at end of file