ElementTag.java

package com.denizenscript.denizencore.objects.core;

import com.denizenscript.denizencore.objects.*;
import com.denizenscript.denizencore.scripts.commands.Comparable;
import com.denizenscript.denizencore.tags.*;
import com.denizenscript.denizencore.utilities.CoreUtilities;
import com.denizenscript.denizencore.utilities.Deprecations;
import com.denizenscript.denizencore.utilities.SQLEscaper;
import com.denizenscript.denizencore.utilities.debugging.Debug;
import com.denizenscript.denizencore.tags.core.EscapeTagBase;

import javax.xml.bind.DatatypeConverter;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.text.DecimalFormat;
import java.util.Arrays;
import java.util.Base64;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class ElementTag implements ObjectTag {

    // <--[language]
    // @name ElementTag Objects
    // @group Object System
    // @description
    // ElementTags are simple objects that contain a simple bit of text.
    // Their main usage is within the replaceable tag system,
    // often times returned from the use of another tag that isn't returning a specific object type, such as a location or entity.
    // For example, <player.name> or <list[item1|item2|item3].comma_separated> will both return ElementTags.
    //
    // Pluses to the ElementTag system is the ability to utilize its tag attributes,
    // which can provide a range of functionality that should be familiar from any other programming language,
    // such as 'to_uppercase', 'split', 'replace', 'contains', and many more.
    // See 'ElementTag.*' tags for more information.
    //
    // While information fetched from other tags resulting in an ElementTag is often times automatically handled,
    // it may be desirable to utilize element attributes from text/numbers/etc. that aren't already an element object.
    // To accomplish this, the standard 'element' tag base can be used for the creation of a new element.
    // For example: <element[This_is_a_test].to_uppercase>
    // will result in the value 'THIS_IS_A_TEST'.
    //
    // Note that while other objects often return their object identifier (p@, li@, e@, etc.), elements do not.
    //
    // For format info, see <@link language el@>
    // -->

    // <--[language]
    // @name ElementTag(Boolean)
    // @group Object System
    // @description
    // When "ElementTag(Boolean)" appears in meta documentation, this means the input/output is an ElementTag
    // (refer to <@link language ElementTag Objects>) that is a boolean.
    // Boolean means either a "true" or a "false".
    // -->

    // <--[language]
    // @name ElementTag(Number)
    // @group Object System
    // @description
    // When "ElementTag(Number)" appears in meta documentation, this means the input/output is an ElementTag
    // (refer to <@link language ElementTag Objects>) that is an integer number.
    // That is, for example: 0, 1, 5, -4, 10002325 or any other number.
    // This does NOT include decimal numbers (like 1.5). Those will be documented as <@link language ElementTag(Decimal)>.
    //
    // In some cases, this will also be documented as "<#>".
    // -->

    // <--[language]
    // @name ElementTag(Decimal)
    // @group Object System
    // @description
    // When "ElementTag(Decimal)" appears in meta documentation, this means the input/output is an ElementTag
    // (refer to <@link language ElementTag Objects>) that is a decimal number.
    // That is, for example: 0, 1, 5, -4, 10002325, 4.2, -18.281241 or any other number.
    // While this is specifically for decimal numbers, the decimal itself is optional (will be assumed as ".0").
    //
    // In some cases, this will also be documented as "<#.#>".
    // -->

    @Deprecated
    public final static ElementTag TRUE = new ElementTag(Boolean.TRUE);
    @Deprecated
    public final static ElementTag FALSE = new ElementTag(Boolean.FALSE);
    @Deprecated
    public final static ElementTag SERVER = new ElementTag("server");
    @Deprecated
    public final static ElementTag NULL = new ElementTag("null");

    final static Pattern VALUE_PATTERN =
            Pattern.compile("el@val(?:ue)?\\[([^\\[\\]]+)\\].*",
                    Pattern.CASE_INSENSITIVE | Pattern.DOTALL | Pattern.MULTILINE);

    public static ElementTag valueOf(String string) {
        return valueOf(string, null);
    }

    // <--[language]
    // @name el@
    // @group Object Fetcher System
    // @description
    // el@ refers to the 'object identifier' of an Element. The 'el@' is notation for Denizen's Object
    // Fetcher. The constructor for an ElementTag is just any text.
    //
    // For example 'el@hello' forms an element with text 'hello'.
    //
    // Elements do not output with 'el@' visible. The 'el@' is only for use as a shorthanded constructor.
    // If you need an element constructor, consider using the '<element[text here]>' tag base instead.
    //
    // For general info, see <@link language Element>
    // -->

    @Fetchable("el")
    public static ElementTag valueOf(String string, TagContext context) {
        if (string == null) {
            return null;
        }

        Matcher m = VALUE_PATTERN.matcher(string);

        // Allow construction of elements with el@val[<value>]
        if (m.matches()) {
            String value = m.group(1);
            return new ElementTag(value);
        }

        return new ElementTag(CoreUtilities.toLowerCase(string).startsWith("el@") ? string.substring(3) : string);
    }

    public static boolean matches(String string) {
        return string != null;
    }

    /**
     * Handle null ObjectTags appropriately for potentionally null tags.
     * Will show a dB error message and return Element.NULL for null objects.
     *
     * @param tag    The input string that produced a potentially null object, for debugging.
     * @param object The potentially null object.
     * @param type   The type of object expected, for debugging. (EG: 'dNPC')
     * @return The object or Element.NULL if the object is null.
     */
    public static <T extends ObjectTag> T handleNull(String tag, T object, String type, boolean has_fallback) {
        if (object == null) {
            if (!has_fallback) {
                Debug.echoError("'" + tag + "' is an invalid " + type + "!");
            }
            return null;
        }
        return object;
    }

    private final String element;

    public ElementTag(String string) {
        this.prefix = "element";
        if (string == null) {
            if (Debug.verbose) {
                try {
                    throw new RuntimeException("Trace");
                }
                catch (Exception ex) {
                    Debug.echoError(ex);
                }
                Debug.log("Element - Null construction!");
            }
            this.element = "null";
        }
        else {
            this.element = TagManager.cleanOutput(string);
        }
    }

    public ElementTag(boolean bool) {
        this.prefix = "boolean";
        this.element = String.valueOf(bool);
    }

    public ElementTag(int integer) {
        this.prefix = "number";
        this.element = String.valueOf(integer);
    }

    public ElementTag(byte byt) {
        this.prefix = "number";
        this.element = String.valueOf(byt);
    }

    public ElementTag(short shrt) {
        this.prefix = "number";
        this.element = String.valueOf(shrt);
    }

    public ElementTag(long lng) {
        this.prefix = "number";
        this.element = String.valueOf(lng);
    }

    public ElementTag(BigDecimal bdl) {
        this.prefix = "decimal";
        this.element = CoreUtilities.bigDecToString(bdl);
    }

    public ElementTag(double dbl) {
        this.prefix = "decimal";
        this.element = CoreUtilities.doubleToString(dbl);
    }

    public ElementTag(float flt) {
        this.prefix = "decimal";
        this.element = CoreUtilities.doubleToString(flt);
    }

    public ElementTag(String prefix, String string) {
        if (prefix == null) {
            this.prefix = "element";
        }
        else {
            this.prefix = prefix;
        }
        this.element = TagManager.cleanOutput(string);
    }

    static final BigDecimal max = new BigDecimal("10E1000");

    private BigDecimal getBD(String text) {
        BigDecimal bd = new BigDecimal(text);
        if (bd.compareTo(max) >= 1) {
            Debug.echoError("Unreasonably large number detected!");
            return max;
        }
        return bd;
    }

    public BigDecimal asBigDecimal() {
        return getBD(element.replaceAll("%", ""));
    }

    public double asDouble() {
        return Double.parseDouble(element.replaceAll("%", ""));
    }

    public float asFloat() {
        return Float.parseFloat(element.replaceAll("%", ""));
    }

    public int asInt() {
        try {
            return Integer.parseInt(element.replaceAll("(%)|(\\.\\d+)", ""));
        }
        catch (NumberFormatException ex) {
            Debug.echoError("'" + element + "' is not a valid integer!");
            return 0;
        }
    }

    public long asLong() {
        try {
            return Long.parseLong(element.replaceAll("(%)|(\\.\\d+)", ""));
        }
        catch (NumberFormatException ex) {
            Debug.echoError("'" + element + "' is not a valid integer!");
            return 0;
        }
    }

    public boolean asBoolean() {
        return Boolean.parseBoolean(element.replaceAll("el@", ""));
    }

    public String asString() {
        return element;
    }

    public boolean isBoolean() {
        return (element != null && (element.equalsIgnoreCase("true") || element.equalsIgnoreCase("false")));
    }

    public boolean isDouble() {
        try {
            if (!Double.valueOf(element).isNaN()) {
                return true;
            }
        }
        catch (Exception e) {
        }
        return false;
    }

    public boolean isFloat() {
        try {
            if (!Float.valueOf(element).isNaN()) {
                return true;
            }
        }
        catch (Exception e) {
        }
        return false;
    }

    public boolean isInt() {
        try {
            Integer val = Integer.valueOf(element.replaceAll("(%)|(\\.\\d+)", ""));
            if (val.hashCode() != 0.5) { // if intentionally always passes
                return true;
            }
        }
        catch (Exception e) {
        }
        return false;
    }

    public boolean isString() {
        return (element != null && !element.isEmpty());
    }

    public boolean matchesType(Class<? extends ObjectTag> dClass) {
        return ObjectFetcher.checkMatch(dClass, element);
    }

    public <T extends ObjectTag> T asType(Class<T> dClass, TagContext context) {
        return ObjectFetcher.getObjectFrom(dClass, element, context);
    }

    public boolean matchesEnum(Enum[] values) {
        for (Enum value : values) {
            if (value.name().equalsIgnoreCase(element)) {
                return true;
            }
        }

        return false;
    }

    private String prefix;

    @Override
    public String getObjectType() {
        return "Element";
    }

    @Override
    public String getPrefix() {
        return prefix;
    }

    @Override
    public ObjectTag setPrefix(String prefix) {
        this.prefix = prefix;
        return this;
    }

    @Override
    public String identify() {
        return element;
    }

    @Override
    public String identifySimple() {
        return identify();
    }

    @Override
    public String toString() {
        return identify();
    }

    @Override
    public boolean isUnique() {
        return false;
    }

    public static void registerTags() {

        /////////////////////
        //   CONVERSION ATTRIBUTES
        /////////////////

        registerTag("is", (attribute, object) -> {
            // <--[tag]
            // @attribute <ElementTag.is[<operator>].to[<element>]>
            // @returns ElementTag(Boolean)
            // @group comparison
            // @description
            // Takes an operator, and compares the value of the element to the supplied
            // element. Returns the outcome of the comparable, either true or false. For
            // information on operators, see <@link language operator>.
            // Equivalent to <@link tag ElementTag.is[<operator>].than[<element>]>
            // -->

            // <--[tag]
            // @attribute <ElementTag.is[<operator>].than[<element>]>
            // @returns ElementTag(Boolean)
            // @group comparison
            // @description
            // Takes an operator, and compares the value of the element to the supplied
            // element. Returns the outcome of the comparable, either true or false. For
            // information on operators, see <@link language operator>.
            // Equivalent to <@link tag ElementTag.is[<operator>].to[<element>]>
            // -->
            if (attribute.hasContext(1) && (attribute.startsWith("to", 2) || attribute.startsWith("than", 2)) && attribute.hasContext(2)) {

                // Use the Comparable object as implemented for the IF command. First, a new Comparable!
                Comparable com = new Comparable();

                // Check for negative logic
                String operator;
                if (attribute.getContext(1).startsWith("!")) {
                    operator = attribute.getContext(1).substring(1);
                    com.setNegativeLogic();
                }
                else {
                    operator = attribute.getContext(1);
                }

                // Operator is the value of the .is[] context. Valid are Comparable.Operators, same
                // as used by the IF command.
                Comparable.Operator comparableOperator = null;
                try {
                    comparableOperator = Comparable.Operator.valueOf(operator.replace("==", "EQUALS")
                            .replace(">=", "OR_MORE").replace("<=", "OR_LESS").replace("<", "LESS")
                            .replace(">", "MORE").replace("=", "EQUALS").toUpperCase());
                }
                catch (IllegalArgumentException e) {
                }

                if (comparableOperator != null) {
                    com.setOperator(comparableOperator);

                    // Comparable is the value of this element
                    com.setComparable(object.toString());
                    // Compared_to is the value of the .to[] context.
                    com.setComparedto(attribute.getContext(2));

                    attribute.fulfill(1);

                    return new ElementTag(com.determineOutcome());
                }
                else {
                    attribute.echoError("Unknown operator '" + operator + "'.");
                }
            }

            return null;
        });

        // <--[tag]
        // @attribute <ElementTag.is_boolean>
        // @returns ElementTag(Boolean)
        // @group comparison
        // @description
        // Returns whether the element is a boolean ('true' or 'false').
        // -->
        registerTag("is_boolean", (attribute, object) -> {
            String element = object.element;
            return new ElementTag(element.equalsIgnoreCase("true")
                    || element.equalsIgnoreCase("false"));
        });

        // <--[tag]
        // @attribute <ElementTag.is_integer>
        // @returns ElementTag(Boolean)
        // @group comparison
        // @description
        // Returns whether the element is an integer number (a number without a decimal point).
        // -->
        registerTag("is_integer", (attribute, object) -> {
            if (!ArgumentHelper.integerPrimitive.matcher(object.element).matches()) {
                return new ElementTag(false);
            }
            try {
                object.asLong();
                return new ElementTag(true);
            }
            catch (NumberFormatException ex) {
                return new ElementTag(false);
            }
        });

        // <--[tag]
        // @attribute <ElementTag.is_decimal>
        // @returns ElementTag(Boolean)
        // @group comparison
        // @description
        // Returns whether the element is a valid decimal number (the decimal point is optional).
        // -->
        registerTag("is_decimal", (attribute, object) -> {
            if (!ArgumentHelper.doublePrimitive.matcher(object.element).matches()) {
                return new ElementTag(false);
            }
            try {
                return new ElementTag(object.asBigDecimal() != null);
            }
            catch (NumberFormatException ex) {
                return new ElementTag(false);
            }
        });

        // <--[tag]
        // @attribute <ElementTag.is_odd>
        // @returns ElementTag(Boolean)
        // @group comparison
        // @description
        // Returns whether the element is an odd-valued decimal number. Returns 'false' for non-numbers.
        // -->
        registerTag("is_odd", (attribute, object) -> {
            String element = object.element;
            return new ElementTag(ArgumentHelper.doublePrimitive.matcher(element).matches()
                    && (object.asBigDecimal().longValue() % 2) == 1);
        });

        // <--[tag]
        // @attribute <ElementTag.is_even>
        // @returns ElementTag(Boolean)
        // @group comparison
        // @description
        // Returns whether the element is an even-valued decimal number. Returns 'false' for non-numbers.
        // -->
        registerTag("is_even", (attribute, object) -> {
            String element = object.element;
            return new ElementTag(ArgumentHelper.doublePrimitive.matcher(element).matches()
                    && (object.asBigDecimal().longValue() % 2) == 0);
        });

        // <--[tag]
        // @attribute <ElementTag.as_element>
        // @returns ElementTag
        // @group conversion
        // @description
        // Returns the element as itself.
        // For use in special cases, generally not very useful.
        // -->
        registerTag("as_element", (attribute, object) -> {
            return object;
        }, "aselement");

        // <--[tag]
        // @attribute <ElementTag.as_boolean>
        // @returns ElementTag(Boolean)
        // @group conversion
        // @description
        // Returns the element as true/false.
        // -->
        registerTag("as_boolean", (attribute, object) -> {
            String element = object.element;
            return new ElementTag(element.equalsIgnoreCase("true")
                    || element.equalsIgnoreCase("t")
                    || element.equalsIgnoreCase("1"));
        }, "asboolean");

        // <--[tag]
        // @attribute <ElementTag.as_decimal>
        // @returns ElementTag(Decimal)
        // @group conversion
        // @description
        // Returns the element as a decimal number, or shows an error.
        // -->
        registerTag("as_decimal", (attribute, object) -> {
            String element = object.element;
            try {
                return new ElementTag(Double.valueOf(element));
            }
            catch (NumberFormatException e) {
                if (!attribute.hasAlternative()) {
                    attribute.echoError("'" + element + "' is not a valid decimal number.");
                }
                return null;
            }
        }, "as_double", "asdouble");

        registerTag("as_int", (attribute, object) -> {
            Deprecations.elementAsInTag.warn(attribute.context);
            String element = object.element;
            try {
                return new ElementTag(Double.valueOf(element).longValue());
            }
            catch (NumberFormatException e) {
                if (!attribute.hasAlternative()) {
                    attribute.echoError("'" + element + "' is not a valid decimal number.");
                }
                return null;
            }
        }, "asint");

        // <--[tag]
        // @attribute <ElementTag.truncate>
        // @returns ElementTag(Number)
        // @group conversion
        // @description
        // Returns the element as a number without a decimal by way of stripping the decimal value off the end.
        // That is, rounds towards zero.
        // -->
        registerTag("truncate", (attribute, object) -> {
            try {
                return new ElementTag(object.asBigDecimal().longValue());
            }
            catch (NumberFormatException e) {
                if (!attribute.hasAlternative()) {
                    attribute.echoError("'" + object.element + "' is not a valid decimal number.");
                }
                return null;
            }
        });

        // <--[tag]
        // @attribute <ElementTag.as_money>
        // @returns ElementTag(Decimal)
        // @group conversion
        // @description
        // Returns the element as a number with two decimal places.
        // -->
        registerTag("as_money", (attribute, object) -> {
            String element = object.element;
            try {
                DecimalFormat d = new DecimalFormat("0.00");
                return new ElementTag(d.format(Double.valueOf(element)));
            }
            catch (NumberFormatException e) {
                if (!attribute.hasAlternative()) {
                    attribute.echoError("'" + element + "' is not a valid decimal number.");
                }
                return null;
            }
        }, "asmoney");

        // <--[tag]
        // @attribute <ElementTag.as_list>
        // @returns ListTag
        // @group conversion
        // @description
        // Returns the element as a ListTag.
        // -->
        registerTag("as_list", (attribute, object) -> {
            String element = object.element;
            ListTag obj = handleNull(element, ListTag.valueOf(element), "dList", attribute.hasAlternative());
            return obj;
        }, "aslist");

        // <--[tag]
        // @attribute <ElementTag.as_custom>
        // @returns CustomObject
        // @group conversion
        // @description
        // Returns the element as a custom object.
        // -->
        registerTag("as_custom", (attribute, object) -> {
            String element = object.element;
            CustomObjectTag obj = handleNull(element, CustomObjectTag.valueOf(element, null), "Custom", attribute.hasAlternative());
            return obj;
        }, "ascustom");

        // <--[tag]
        // @attribute <ElementTag.as_script>
        // @returns ScriptTag
        // @group conversion
        // @description
        // Returns the element as a ScriptTag.
        // Note: the value must be a valid script.
        // -->
        registerTag("as_script", (attribute, object) -> {
            String element = object.element;
            return handleNull(element, ScriptTag.valueOf(element), "dScript", attribute.hasAlternative());
        }, "asscript");

        // <--[tag]
        // @attribute <ElementTag.as_queue>
        // @returns QueueTag
        // @group conversion
        // @description
        // Returns the element as a ScriptQueue.
        // Note: the value must be a valid ScriptQueue.
        // -->
        registerTag("as_queue", (attribute, object) -> {
            String element = object.element;
            return handleNull(element, QueueTag.valueOf(element), "ScriptQueue", attribute.hasAlternative());
        }, "asqueue");

        // <--[tag]
        // @attribute <ElementTag.as_duration>
        // @returns DurationTag
        // @group conversion
        // @description
        // Returns the element as a Duration.
        // Note: the value must be a valid Duration.
        // -->
        registerTag("as_duration", (attribute, object) -> {
            String element = object.element;
            return handleNull(element, DurationTag.valueOf(element), "Duration", attribute.hasAlternative());
        }, "asduration");

        // <--[tag]
        // @attribute <ElementTag.escaped>
        // @returns ElementTag
        // @group conversion
        // @description
        // Returns the element, escaped for safe reuse.
        // Inverts <@link tag ElementTag.unescaped>
        // See <@link language property escaping>
        // -->
        registerTag("escaped", (attribute, object) -> {
            String element = object.element;
            return new ElementTag(EscapeTagBase.escape(element));
        });

        // <--[tag]
        // @attribute <ElementTag.sql_escaped>
        // @returns ElementTag
        // @group conversion
        // @description
        // Returns the element, escaped for safe use in SQL.
        // -->
        registerTag("sql_escaped", (attribute, object) -> {
            String element = object.element;
            return new ElementTag(SQLEscaper.escapeSQL(element));
        });

        // <--[tag]
        // @attribute <ElementTag.unescaped>
        // @returns ElementTag
        // @group conversion
        // @description
        // Returns the element, unescaped.
        // Inverts <@link tag ElementTag.escaped>
        // See <@link language property escaping>
        // -->
        registerTag("unescaped", (attribute, object) -> {
            String element = object.element;
            return new ElementTag(EscapeTagBase.unEscape(element));
        });

        // <--[tag]
        // @attribute <ElementTag.parsed>
        // @returns ElementTag
        // @group conversion
        // @description
        // Returns the element, with any contained tags parsed.
        // WARNING: THIS TAG IS DANGEROUS TO USE, DO NOT USE IT UNLESS
        // YOU KNOW WHAT YOU ARE DOING. USE AT YOUR OWN RISK.
        // -->
        registerTag("parsed", (attribute, object) -> {
            return TagManager.tagObject(TagManager.cleanOutputFully(object.element), attribute.context);
        });

        /////////////////////
        //   ELEMENT CHECKING ATTRIBUTES
        /////////////////

        // <--[tag]
        // @attribute <ElementTag.difference[<element>]>
        // @returns ElementTag(Number)
        // @group element checking
        // @description
        // Returns a number representing the difference between the two elements. (Uses Levenshtein logic).
        // -->
        registerTag("difference", (attribute, object) -> {
            String element = object.element;
            String two = attribute.getContext(1);
            return new ElementTag(CoreUtilities.getLevenshteinDistance(element, two));
        });

        // <--[tag]
        // @attribute <ElementTag.contains_any_case_sensitive_text[<element>|...]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element contains any of a list of specified elements, case sensitive.
        // -->
        registerTag("contains_any_case_sensitive", (attribute, object) -> {
            String element = object.element;
            ListTag list = ListTag.valueOf(attribute.getContext(1));
            for (String list_element : list) {
                if (element.contains(list_element)) {
                    return new ElementTag(true);
                }
            }
            return new ElementTag(false);
        });
        TagRunnable.ObjectInterface<ElementTag> r = tagProcessor.registeredObjectTags.get("contains_any_case_sensitive");
        registerTag("contains_any_case_sensitive_text", r);

        // <--[tag]
        // @attribute <ElementTag.contains_any_text[<element>|...]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element contains any of a list of specified elements, case insensitive.
        // -->
        registerTag("contains_any", (attribute, object) -> {
            String element = object.element;
            ListTag list = ListTag.valueOf(CoreUtilities.toLowerCase(attribute.getContext(1)));
            String ellow = CoreUtilities.toLowerCase(element);
            for (String list_element : list) {
                if (ellow.contains(list_element)) {
                    return new ElementTag(true);
                }
            }
            return new ElementTag(false);
        });
        r = tagProcessor.registeredObjectTags.get("contains_any");
        registerTag("contains_any_text", r);

        // <--[tag]
        // @attribute <ElementTag.contains_case_sensitive_text[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element contains a specified element, case sensitive.
        // -->
        registerTag("contains_case_sensitive", (attribute, object) -> {
            String element = object.element;
            String contains = attribute.getContext(1);
            if (element.contains(contains)) {
                return new ElementTag("true");
            }
            else {
                return new ElementTag("false");
            }
        });
        r = tagProcessor.registeredObjectTags.get("contains_case_sensitive");
        registerTag("contains_case_sensitive_text", r);

        // <--[tag]
        // @attribute <ElementTag.contains_text[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element contains a specified element, case insensitive. Can use
        // regular expression by prefixing the element with regex:
        // -->
        registerTag("contains", (attribute, object) -> {
            String element = object.element;
            String contains = attribute.getContext(1);

            if (CoreUtilities.toLowerCase(contains).startsWith("regex:")) {

                if (Pattern.compile(contains.substring(("regex:").length()), Pattern.CASE_INSENSITIVE).matcher(element).matches()) {
                    return new ElementTag("true");
                }
                else {
                    return new ElementTag("false");
                }
            }
            else if (CoreUtilities.toLowerCase(element).contains(CoreUtilities.toLowerCase(contains))) {
                return new ElementTag("true");
            }
            else {
                return new ElementTag("false");
            }
        });
        r = tagProcessor.registeredObjectTags.get("contains");
        registerTag("contains_text", r);

        // <--[tag]
        // @attribute <ElementTag.contains_all_text[<element>|...]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element contains all of the specified strings, case insensitive.
        // -->
        registerTag("contains_all", (attribute, object) -> {
            String element = object.element;
            ListTag list = ListTag.valueOf(CoreUtilities.toLowerCase(attribute.getContext(1)));
            String ellow = CoreUtilities.toLowerCase(element);
            for (String list_element : list) {
                if (!ellow.contains(list_element)) {
                    return new ElementTag("false");
                }
            }
            return new ElementTag("true");
        });
        r = tagProcessor.registeredObjectTags.get("contains_all");
        registerTag("contains_all_text", r);

        // <--[tag]
        // @attribute <ElementTag.contains_all_case_sensitive_text[<element>|...]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element contains all of the specified strings, case sensitive.
        // -->
        registerTag("contains_all_case_sensitive", (attribute, object) -> {
            String element = object.element;
            ListTag list = ListTag.valueOf(attribute.getContext(1));
            for (String list_element : list) {
                if (!element.contains(list_element)) {
                    return new ElementTag("false");
                }
            }
            return new ElementTag("true");
        });
        r = tagProcessor.registeredObjectTags.get("contains_all_case_sensitive");
        registerTag("contains_all_case_sensitive_text", r);

        // <--[tag]
        // @attribute <ElementTag.ends_with[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element ends with a specified element.
        // -->
        registerTag("ends_with", (attribute, object) -> {
            return new ElementTag(CoreUtilities.toLowerCase(object.element).
                    endsWith(CoreUtilities.toLowerCase(attribute.getContext(1))));
        }, "endswith");

        // <--[tag]
        // @attribute <ElementTag.equals_case_sensitive[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element matches another element, case-sensitive.
        // -->
        registerTag("equals_case_sensitive", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.equals_case_sensitive[...] must have a value.");
                return null;
            }
            return new ElementTag(object.element.equals(attribute.getContext(1)));
        }, "equals_with_case");

        // <--[tag]
        // @attribute <ElementTag.matches[<regex>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element matches a regex input.
        // -->
        registerTag("matches", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.matches[...] must have a value.");
                return null;
            }
            return new ElementTag(object.element.matches(attribute.getContext(1)));
        });

        // <--[tag]
        // @attribute <ElementTag.regex[<regex>].group[<group>]>
        // @returns ElementTag
        // @group element checking
        // @description
        // Returns the specific group from a regex match.
        // Specify group 0 for the whole match.
        // For example, <element[hello5world].regex[.*(\d).*].group[1]> returns '5'.
        // -->
        registerTag("regex", (attribute, object) -> {
            if (!attribute.hasContext(1) || !attribute.hasContext(2)) {
                attribute.echoError("The tag ElementTag.regex[...] must have a value.");
                return null;
            }
            String regex = attribute.getContext(1);
            Matcher m = Pattern.compile(regex).matcher(object.element);
            if (!m.matches()) {
                return null;
            }
            int group = new ElementTag(attribute.getContext(2)).asInt();
            if (group < 0) {
                group = 0;
            }
            if (group > m.groupCount()) {
                group = m.groupCount();
            }
            attribute.fulfill(1);
            return new ElementTag(m.group(group));
        });

        // <--[tag]
        // @attribute <ElementTag.length>
        // @returns ElementTag(Number)
        // @group element checking
        // @description
        // Returns the length of the element.
        // -->
        registerTag("length", (attribute, object) -> {
            return new ElementTag(object.element.length());
        });

        // <--[tag]
        // @attribute <ElementTag.not>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns the opposite of the element
        // IE, true returns false and false returns true.
        // -->
        registerTag("not", (attribute, object) -> {
            return new ElementTag(!object.element.equalsIgnoreCase("true"));
        });

        // <--[tag]
        // @attribute <ElementTag.and[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether both the element and the second element are true.
        // -->
        registerTag("and", (attribute, object) -> {
            return new ElementTag(object.element.equalsIgnoreCase("true") && attribute.getContext(1).equalsIgnoreCase("true"));
        });

        // <--[tag]
        // @attribute <ElementTag.or[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether either the element or the second element are true.
        // -->
        registerTag("or", (attribute, object) -> {
            return new ElementTag(object.element.equalsIgnoreCase("true") || attribute.getContext(1).equalsIgnoreCase("true"));
        });

        // <--[tag]
        // @attribute <ElementTag.xor[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element and the second element are true and false (exclusive or).
        // -->
        registerTag("xor", (attribute, object) -> {
            return new ElementTag(object.element.equalsIgnoreCase("true") != attribute.getContext(1).equalsIgnoreCase("true"));
        });

        // <--[tag]
        // @attribute <ElementTag.starts_with[<element>]>
        // @returns ElementTag(Boolean)
        // @group element checking
        // @description
        // Returns whether the element starts with a specified element.
        // -->
        registerTag("starts_with", (attribute, object) -> {
            return new ElementTag(CoreUtilities.toLowerCase(object.element).startsWith(CoreUtilities.toLowerCase(attribute.getContext(1))));
        }, "startswith");

        // <--[tag]
        // @attribute <ElementTag.index_of[<element>]>
        // @returns ElementTag(Number)
        // @group element checking
        // @description
        // Returns the index of the first occurrence of a specified element.
        // Returns 0 if the element never occurs within the element.
        // -->
        registerTag("index_of", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.index_of[...] must have a value.");
                return null;
            }
            return new ElementTag(CoreUtilities.toLowerCase(object.element)
                    .indexOf(CoreUtilities.toLowerCase(attribute.getContext(1))) + 1);
        });

        // <--[tag]
        // @attribute <ElementTag.last_index_of[<element>]>
        // @returns ElementTag(Number)
        // @group element checking
        // @description
        // Returns the index of the last occurrence of a specified element.
        // Returns 0 if the element never occurs within the element.
        // -->
        registerTag("last_index_of", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.last_index_of[...] must have a value.");
                return null;
            }
            return new ElementTag(CoreUtilities.toLowerCase(object.element)
                    .lastIndexOf(CoreUtilities.toLowerCase(attribute.getContext(1))) + 1);
        });

        // <--[tag]
        // @attribute <ElementTag.char_at[<#>]>
        // @returns ElementTag
        // @group element checking
        // @description
        // Returns the character at a specified index.
        // Returns null if the index is outside the range of the element.
        // -->
        registerTag("char_at", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.char_at[...] must have a value.");
                return null;
            }
            int index = attribute.getIntContext(1) - 1;
            if (index < 0 || index >= object.element.length()) {
                return null;
            }
            else {
                return new ElementTag(String.valueOf(object.element.charAt(index)));
            }
        });

        /////////////////////
        //   ELEMENT MANIPULATION ATTRIBUTES
        /////////////////

        // <--[tag]
        // @attribute <ElementTag.after_last[<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the portion of an element after the last occurrence of a specified element.
        // For example: abcabc .after_last[b] returns c.
        // -->
        registerTag("after_last", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.after_last[...] must have a value.");
                return null;
            }
            String delimiter = attribute.getContext(1);
            if (CoreUtilities.toLowerCase(object.element).contains(CoreUtilities.toLowerCase(delimiter))) {
                return new ElementTag(object.element.substring
                        (CoreUtilities.toLowerCase(object.element).lastIndexOf(CoreUtilities.toLowerCase(delimiter)) + delimiter.length()));
            }
            else {
                return new ElementTag("");
            }
        });

        // <--[tag]
        // @attribute <ElementTag.after[<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the portion of an element after the first occurrence of a specified element.
        // For example: HelloWorld .after[Hello] returns World.
        // -->
        registerTag("after", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.after[...] must have a value.");
                return null;
            }
            String delimiter = attribute.getContext(1);
            if (CoreUtilities.toLowerCase(object.element).contains(CoreUtilities.toLowerCase(delimiter))) {
                return new ElementTag(object.element.substring
                        (CoreUtilities.toLowerCase(object.element).indexOf(CoreUtilities.toLowerCase(delimiter)) + delimiter.length()));
            }
            else {
                return new ElementTag("");
            }
        });

        // <--[tag]
        // @attribute <ElementTag.before_last[<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the portion of an element before the last occurrence of a specified element.
        // For example: abcabc .before_last[b] returns abca.
        // -->
        registerTag("before_last", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.before_last[...] must have a value.");
                return null;
            }
            String delimiter = attribute.getContext(1);
            if (CoreUtilities.toLowerCase(object.element).contains(CoreUtilities.toLowerCase(delimiter))) {
                return new ElementTag(object.element.substring
                        (0, CoreUtilities.toLowerCase(object.element).lastIndexOf(CoreUtilities.toLowerCase(delimiter))));
            }
            else {
                return new ElementTag(object.element);
            }
        });

        // <--[tag]
        // @attribute <ElementTag.before[<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the portion of an element before the first occurrence of specified element.
        // For example: abcd .before[c] returns ab.
        // -->
        registerTag("before", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.before[...] must have a value.");
                return null;
            }
            String delimiter = attribute.getContext(1);
            if (CoreUtilities.toLowerCase(object.element).contains(CoreUtilities.toLowerCase(delimiter))) {
                return new ElementTag(object.element.substring
                        (0, CoreUtilities.toLowerCase(object.element).indexOf(CoreUtilities.toLowerCase(delimiter))));
            }
            else {
                return new ElementTag(object.element);
            }
        });

        // <--[tag]
        // @attribute <ElementTag.replace[((first)regex:)<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the element with all instances of a element removed.
        // -->

        // <--[tag]
        // @attribute <ElementTag.replace[((first)regex:)<element>].with[<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the element with all instances of a element replaced with another.
        // Specify regex: at the start of the replace element to use Regex replacement.
        // Specify firstregex: at the start of the replace element to Regex 'replaceFirst'
        // -->
        registerTag("replace", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.replace[...] must have a value.");
                return null;
            }
            String replace = attribute.getContext(1);
            String replacement = "";
            if (attribute.startsWith("with", 2)) {
                if (attribute.hasContext(2)) {
                    replacement = attribute.getContext(2);
                    if (replacement == null) {
                        attribute.echoError("The tag ElementTag.replace[...].with[...] must have a value.");
                        return null;
                    }
                    attribute.fulfill(1);
                }
            }

            if (replace.startsWith("regex:")) {
                return new ElementTag(object.element.replaceAll(replace.substring("regex:".length()), replacement));
            }
            if (replace.startsWith("firstregex:")) {
                return new ElementTag(object.element.replaceFirst(replace.substring("firstregex:".length()), replacement));
            }
            else {
                return new ElementTag(object.element.replaceAll("(?i)" + Pattern.quote(replace), replacement));
            }
        });
        // <--[tag]
        // @attribute <ElementTag.replace_text[((first)regex:)<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the element with all instances of a element removed.
        // -->

        // <--[tag]
        // @attribute <ElementTag.replace_text[((first)regex:)<element>].with[<element>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the element with all instances of a element replaced with another.
        // Specify regex: at the start of the replace element to use Regex replacement.
        // Specify firstregex: at the start of the replace element to Regex 'replaceFirst'
        // -->
        r = tagProcessor.registeredObjectTags.get("replace");
        registerTag("replace_text", r);

        // <--[tag]
        // @attribute <ElementTag.format_number[(<format>)]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns a number reformatted for easier reading.
        // For example: 1234567 will become 1,234,567.
        // Optionally, specify a standard number format code to instead use that.
        // For information on that optional input, refer to <@link url https://docs.oracle.com/javase/7/docs/api/java/text/DecimalFormat.html>.
        // -->
        registerTag("format_number", (attribute, object) -> {
            try {
                if (attribute.hasContext(1)) {
                    DecimalFormat format = new DecimalFormat(attribute.getContext(1));
                    return new ElementTag(format.format(object.asBigDecimal()));
                }
                int decimal = object.element.indexOf('.');
                String shortelement;
                String afterdecimal;
                if (decimal != -1) {
                    shortelement = object.element.substring(0, decimal);
                    afterdecimal = object.element.substring(decimal);
                }
                else {
                    shortelement = object.element;
                    afterdecimal = "";
                }
                String intform = Long.valueOf(shortelement.replace("%", "")).toString();
                String negative = "";
                if (intform.startsWith("-")) {
                    negative = "-";
                    intform = intform.substring(1);
                }
                for (int i = intform.length() - 3; i > 0; i -= 3) {
                    intform = intform.substring(0, i) + "," + intform.substring(i);
                }
                return new ElementTag(negative + intform + afterdecimal);
            }
            catch (Exception ex) {
                attribute.echoError(ex);
            }
            return null;
        });

        // <--[tag]
        // @attribute <ElementTag.to_list>
        // @returns ListTag
        // @group element manipulation
        // @description
        // Returns a ListTag of each letter in the element.
        // -->
        registerTag("to_list", (attribute, object) -> {
            ListTag list = new ListTag();
            for (int i = 0; i < object.element.length(); i++) {
                list.add(String.valueOf(object.element.charAt(i)));
            }
            return list;
        });

        // <--[tag]
        // @attribute <ElementTag.trim>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the value of an element minus any leading or trailing whitespace.
        // -->
        registerTag("trim", (attribute, object) -> {
            return new ElementTag(object.element.trim());
        });

        // <--[tag]
        // @attribute <ElementTag.to_uppercase>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the value of an element in all uppercase letters.
        // -->
        registerTag("to_uppercase", (attribute, object) -> {
            return new ElementTag(object.element.toUpperCase());
        }, "upper");

        // <--[tag]
        // @attribute <ElementTag.to_lowercase>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the value of an element in all lowercase letters.
        // -->
        registerTag("to_lowercase", (attribute, object) -> {
            return new ElementTag(CoreUtilities.toLowerCase(object.element));
        }, "lower");

        // <--[tag]
        // @attribute <ElementTag.to_titlecase>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns The Value Of An ElementTag In Title Case.
        // -->
        registerTag("to_titlecase", (attribute, object) -> {
            if (object.element.length() == 0) {
                return new ElementTag("");
            }
            StringBuilder TitleCase = new StringBuilder(object.element.length());
            String Upper = object.element.toUpperCase();
            String Lower = CoreUtilities.toLowerCase(object.element);
            TitleCase.append(Upper.charAt(0));
            for (int i = 1; i < object.element.length(); i++) {
                if (object.element.charAt(i - 1) == ' ') {
                    TitleCase.append(Upper.charAt(i));
                }
                else {
                    TitleCase.append(Lower.charAt(i));
                }
            }
            return new ElementTag(TitleCase.toString());
        }, "totitlecase");

        // <--[tag]
        // @attribute <ElementTag.substring[<#>(,<#>)]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the portion of an element between two element indices.
        // If no second index is specified, it will return the portion of an
        // element after the specified index.
        // -->
        registerTag("substring", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.substring[...] must have a value.");
                return null;
            }
            int beginning_index = new ElementTag(attribute.getContext(1).split(",")[0]).asInt() - 1;
            int ending_index;
            if (attribute.getContext(1).split(",").length > 1) {
                ending_index = new ElementTag(attribute.getContext(1).split(",")[1]).asInt();
            }
            else {
                ending_index = object.element.length();
            }
            if (beginning_index < 0) {
                beginning_index = 0;
            }
            if (beginning_index > object.element.length()) {
                beginning_index = object.element.length();
            }
            if (ending_index > object.element.length()) {
                ending_index = object.element.length();
            }
            if (ending_index < beginning_index) {
                ending_index = beginning_index;
            }
            return new ElementTag(object.element.substring(beginning_index, ending_index));
        }, "substr");

        // <--[tag]
        // @attribute <ElementTag.split[(regex:)<string>]>
        // @returns ListTag
        // @group element manipulation
        // @description
        // Returns a list of portions of this element, split by the specified string.
        // If a split string is unspecified, splits by space.
        // -->
        registerTag("split", (attribute, object) -> {
            String split_string = (attribute.hasContext(1) ? attribute.getContext(1) : " ");
            if (CoreUtilities.toLowerCase(split_string).startsWith("regex:")) {
                split_string = split_string.split(":", 2)[1];
            }
            else {
                split_string = "(?i)" + Pattern.quote(split_string);
            }
            String[] split;

            // <--[tag]
            // @attribute <ElementTag.split[(regex:)<string>].limit[<#>]>
            // @returns ListTag
            // @group element manipulation
            // @description
            // Returns a list of portions of this element, split by the specified string,
            // and capped at the specified number of max list items.
            // If a split string is unspecified, splits by space.
            // -->
            if (attribute.startsWith("limit", 2)) {
                int limit = (attribute.hasContext(2) ? attribute.getIntContext(2) : 1);
                attribute.fulfill(1);
                split = object.element.split(split_string, limit);
            }
            else {
                split = object.element.split(split_string);
            }
            return new ListTag(Arrays.asList(split));
        });

        // <--[tag]
        // @attribute <ElementTag.pad_left[<#>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the value of an element extended to reach a minimum specified length
        // by adding spaces to the left side.
        // -->
        registerTag("pad_left", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.pad_left[...] must have a value.");
                return null;
            }
            String with = String.valueOf((char) 0x00A0);
            int length = attribute.getIntContext(1);

            // <--[tag]
            // @attribute <ElementTag.pad_left[<#>].with[<element>]>
            // @returns ElementTag
            // @group element manipulation
            // @description
            // Returns the value of an element extended to reach a minimum specified length
            // by adding a specific symbol to the left side.
            // -->
            if (attribute.startsWith("with", 2) && attribute.hasContext(2)) {
                with = String.valueOf(attribute.getContext(2).charAt(0));
                attribute.fulfill(1);
            }
            StringBuilder padded = new StringBuilder();
            length -= object.element.length();
            while (padded.length() < length) {
                padded.append(with);
            }
            padded.append(object.element);
            return new ElementTag(padded.toString());
        });

        // <--[tag]
        // @attribute <ElementTag.pad_right[<#>]>
        // @returns ElementTag
        // @group element manipulation
        // @description
        // Returns the value of an element extended to reach a minimum specified length
        // by adding spaces to the right side.
        // -->
        registerTag("pad_right", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.pad_right[...] must have a value.");
                return null;
            }
            String with = String.valueOf((char) 0x00A0);
            int length = attribute.getIntContext(1);

            // <--[tag]
            // @attribute <ElementTag.pad_right[<#>].with[<element>]>
            // @returns ElementTag
            // @group element manipulation
            // @description
            // Returns the value of an element extended to reach a minimum specified length
            // by adding a specific symbol to the right side.
            // -->
            if (attribute.startsWith("with", 2) && attribute.hasContext(2)) {
                with = String.valueOf(attribute.getContext(2).charAt(0));
                attribute.fulfill(1);
            }
            StringBuilder padded = new StringBuilder(object.element);
            while (padded.length() < length) {
                padded.append(with);
            }
            return new ElementTag(padded.toString());
        });

        /////////////////////
        //   MATH ATTRIBUTES
        /////////////////

        // <--[tag]
        // @attribute <ElementTag.abs>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the absolute value of the element.
        // -->
        registerTag("abs", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.abs(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.max[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the higher number: this element or the specified one.
        // -->
        registerTag("max", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.max(ele.asDouble(), new ElementTag(attribute.getContext(1)).asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.min[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the lower number: this element or the specified one.
        // -->
        registerTag("min", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.min(ele.asDouble(), new ElementTag(attribute.getContext(1)).asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.add_int[<#>]>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Returns the element plus a number, using integer math.
        // -->
        registerTag("add_int", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(ele.asLong() + attribute.getLongContext(1));
        });

        // <--[tag]
        // @attribute <ElementTag.div_int[<#>]>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Returns the element divided by a number.
        // -->
        registerTag("div_int", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(ele.asLong() / attribute.getLongContext(1));
        });

        // <--[tag]
        // @attribute <ElementTag.mul_int[<#>]>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Returns the element multiplied by a number.
        // -->
        registerTag("mul_int", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(ele.asLong() * attribute.getLongContext(1));
        });

        // <--[tag]
        // @attribute <ElementTag.sub_int[<#>]>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Returns the element minus a number.
        // -->
        registerTag("sub_int", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(ele.asLong() - attribute.getLongContext(1));
        });

        // <--[tag]
        // @attribute <ElementTag.add[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the element plus a number.
        // -->
        TagRunnable.ObjectInterface<ElementTag> addRunnable = (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.add[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            try {
                return new ElementTag(object.asBigDecimal().add(object.getBD(attribute.getContext(1))));
            }
            catch (Throwable e) {
                return new ElementTag(object.asDouble() + attribute.getDoubleContext(1));
            }
        };
        registerTag("add", addRunnable);
        registerTag("+", addRunnable);

        // <--[tag]
        // @attribute <ElementTag.div[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the element divided by a number.
        // -->
        TagRunnable.ObjectInterface<ElementTag> divRunnable = (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.div[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            try {
                return new ElementTag(object.asBigDecimal().divide(object.getBD(attribute.getContext(1)), 64, RoundingMode.HALF_UP));
            }
            catch (Throwable e) {
                return new ElementTag(object.asDouble() / attribute.getDoubleContext(1));
            }
        };
        registerTag("div", divRunnable);
        registerTag("/", divRunnable);

        // <--[tag]
        // @attribute <ElementTag.mod[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the remainder of the element divided by a number.
        // -->
        TagRunnable.ObjectInterface<ElementTag> modRunnable = (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.mod[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(object.asDouble() % attribute.getDoubleContext(1));
        };
        registerTag("mod", modRunnable);
        registerTag("%", modRunnable);

        // <--[tag]
        // @attribute <ElementTag.mul[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the element multiplied by a number.
        // -->
        TagRunnable.ObjectInterface<ElementTag> mulRunnable = (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.mul[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            try {
                return new ElementTag(object.asBigDecimal().multiply(object.getBD(attribute.getContext(1))));
            }
            catch (Throwable e) {
                return new ElementTag(object.asDouble() * attribute.getDoubleContext(1));
            }
        };
        registerTag("mul", mulRunnable);
        registerTag("*", mulRunnable);

        // <--[tag]
        // @attribute <ElementTag.sub[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the element minus a number.
        // -->
        TagRunnable.ObjectInterface<ElementTag> subRunnable = (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.sub[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            try {
                return new ElementTag(object.asBigDecimal().subtract(object.getBD(attribute.getContext(1))));
            }
            catch (Throwable e) {
                return new ElementTag(object.asDouble() - attribute.getDoubleContext(1));
            }
        };
        registerTag("sub", subRunnable);
        registerTag("-", subRunnable);

        // <--[tag]
        // @attribute <ElementTag.sqrt>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the square root of the element.
        // -->
        registerTag("sqrt", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.sqrt(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.log[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the logarithm of the element, with the base of the specified number.
        // -->
        registerTag("log", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.log[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.log(object.asDouble()) / Math.log(attribute.getDoubleContext(1)));
        });

        // <--[tag]
        // @attribute <ElementTag.ln>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the natural logarithm of the element.
        // -->
        registerTag("ln", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.log(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.power[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the element to the power of a number.
        // -->
        TagRunnable.ObjectInterface<ElementTag> powerRunnable = (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.power[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.pow(object.asDouble(), attribute.getDoubleContext(1)));
        };
        registerTag("power", powerRunnable);
        registerTag("^", powerRunnable);

        // <--[tag]
        // @attribute <ElementTag.asin>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the arc-sine of the element.
        // -->
        registerTag("asin", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.asin(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.acos>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the arc-cosine of the element.
        // -->
        registerTag("acos", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.acos(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.atan>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the arc-tangent of the element.
        // -->
        registerTag("atan", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.atan(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.atan2[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Interprets the element to be a Y value and the input value to be an X value (meaning: <Y.atan2[X]>),
        // and returns an angle representing the vector of (X,Y).
        // -->
        registerTag("atan2", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.atan2[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.atan2(object.asDouble(), attribute.getDoubleContext(1)));
        });

        // <--[tag]
        // @attribute <ElementTag.cos>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the cosine of the element.
        // -->
        registerTag("cos", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.cos(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.sin>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the sine of the element.
        // -->
        registerTag("sin", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.sin(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.tan>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Returns the tangent of the element.
        // -->
        registerTag("tan", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.tan(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.factorial>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Returns the factorial of the element. This should only be used for small values (generally: less than 20), and will become ridiculous/unusable at larger values.
        // -->
        registerTag("factorial", (attribute, ele) -> {
            if (!ele.isInt()) {
                attribute.echoError("Element '" + ele + "' is not a valid number!");
                return null;
            }
            int count = ele.asInt();
            BigInteger result = BigInteger.ONE;
            for (int i = 2; i <= count; i++) {
                result = result.multiply(BigInteger.valueOf(i));
            }
            return new ElementTag(result.toString());
        });

        // <--[tag]
        // @attribute <ElementTag.to_degrees>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Converts the element from radians to degrees.
        // -->
        registerTag("to_degrees", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.toDegrees(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.to_radians>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Converts the element from degrees to radians.
        // -->
        registerTag("to_radians", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.toRadians(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.round_up>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Rounds a decimal upward.
        // -->
        registerTag("round_up", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag((long) Math.ceil(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.round_down>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Rounds a decimal downward.
        // -->
        registerTag("round_down", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag((long) Math.floor(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.round_to[<#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Rounds a decimal to the specified place.
        // For example, 0.12345 .round_to[3] returns "0.123".
        // -->
        registerTag("round_to", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.round_to[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            int ten = (int) Math.pow(10, attribute.getIntContext(1));
            return new ElementTag(((double) Math.round(object.asDouble() * ten)) / ten);
        });

        // <--[tag]
        // @attribute <ElementTag.round>
        // @returns ElementTag(Number)
        // @group math
        // @description
        // Rounds a decimal.
        // -->
        registerTag("round", (attribute, ele) -> {
            if (!ele.isDouble()) {
                attribute.echoError("Element '" + ele + "' is not a valid decimal number!");
                return null;
            }
            return new ElementTag(Math.round(ele.asDouble()));
        });

        // <--[tag]
        // @attribute <ElementTag.round_to_precision[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Rounds a decimal to the specified precision.
        // For example, 0.12345 .round_to_precision[0.005] returns "0.125".
        // -->
        registerTag("round_to_precision", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.round_to_precision[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            double precision = attribute.getDoubleContext(1);
            return new ElementTag(((double) Math.round(object.asDouble() / precision)) * precision);
        });

        // <--[tag]
        // @attribute <ElementTag.round_down_to_precision[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Rounds a decimal downward to the specified precision.
        // -->
        registerTag("round_down_to_precision", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.round_down_to_precision[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            double precision = attribute.getDoubleContext(1);
            return new ElementTag(Math.floor(object.asDouble() / precision) * precision);
        });

        // <--[tag]
        // @attribute <ElementTag.round_up_to_precision[<#.#>]>
        // @returns ElementTag(Decimal)
        // @group math
        // @description
        // Rounds a decimal upward to the specified precision.
        // -->
        registerTag("round_up_to_precision", (attribute, object) -> {
            if (!attribute.hasContext(1)) {
                attribute.echoError("The tag ElementTag.round_up_to_precision[...] must have a value.");
                return null;
            }
            if (!object.isDouble()) {
                attribute.echoError("Element '" + object + "' is not a valid decimal number!");
                return null;
            }
            double precision = attribute.getDoubleContext(1);
            return new ElementTag(Math.ceil(object.asDouble() / precision) * precision);
        });

        // <--[tag]
        // @attribute <ElementTag.base64_encode>
        // @returns ElementTag
        // @group conversion
        // @description
        // Encodes the element using Base64 encoding.
        // -->
        registerTag("base64_encode", (attribute, object) -> {
            String encoded = Base64.getEncoder().encodeToString(object.element.getBytes());
            return new ElementTag(encoded);
        });

        // <--[tag]
        // @attribute <ElementTag.base64_decode>
        // @returns ElementTag
        // @group conversion
        // @description
        // Decodes the element using Base64 encoding. Must be valid Base64 input.
        // -->
        registerTag("base64_decode", (attribute, object) -> {
            String decoded = new String(Base64.getDecoder().decode(object.element));
            return new ElementTag(decoded);
        });

        // <--[tag]
        // @attribute <ElementTag.hex_encode>
        // @returns ElementTag
        // @group conversion
        // @description
        // Encodes the element using hexadecimal encoding.
        // -->
        registerTag("hex_encode", (attribute, object) -> {
            String encoded = DatatypeConverter.printHexBinary(object.element.getBytes());
            return new ElementTag(encoded);
        });

        // <--[tag]
        // @attribute <ElementTag.hex_decode>
        // @returns ElementTag
        // @group conversion
        // @description
        // Decodes the element using hexadecimal encoding. Must be valid hexadecimal input.
        // -->
        registerTag("hex_decode", (attribute, object) -> {
            String decoded = new String(DatatypeConverter.parseHexBinary(object.element));
            return new ElementTag(decoded);
        });

        // <--[tag]
        // @attribute <ElementTag.url_encode>
        // @returns ElementTag
        // @group conversion
        // @description
        // Encodes the element using URL encoding.
        // -->
        registerTag("url_encode", (attribute, object) -> {
            try {
                String encoded = URLEncoder.encode(object.element, "UTF-8");
                return new ElementTag(encoded);
            }
            catch (Exception e) {
                attribute.echoError(e);
                return null;
            }
        });

        // <--[tag]
        // @attribute <ElementTag.url_decode>
        // @returns ElementTag
        // @group conversion
        // @description
        // Decodes the element using URL encoding. Must be valid URL-encoded input.
        // -->
        registerTag("url_decode", (attribute, object) -> {
            try {
                String decoded = URLDecoder.decode(object.element, "UTF-8");
                return new ElementTag(decoded);
            }
            catch (Exception e) {
                attribute.echoError(e);
                return null;
            }
        });

        // <--[tag]
        // @attribute <ElementTag.type>
        // @returns ElementTag
        // @description
        // Always returns 'Element' for ElementTag objects. All objects fetchable by the Object Fetcher will return the
        // type of object that is fulfilling this attribute.
        // -->
        registerTag("type", (attribute, object) -> {
            return new ElementTag("Element");
        });
    }

    public static ObjectTagProcessor<ElementTag> tagProcessor = new ObjectTagProcessor<>();

    public static void registerTag(String name, TagRunnable.ObjectInterface<ElementTag> runnable, String... variants) {
        tagProcessor.registerTag(name, runnable, variants);
    }

    @Override
    public ObjectTag getObjectAttribute(Attribute attribute) {
        return tagProcessor.getObjectAttribute(this, attribute);
    }

    public static class FailedObjectTag implements ObjectTag {
        @Override
        public String getPrefix() {
            return null;
        }
        @Override
        public boolean isUnique() {
            return false;
        }
        @Override
        public String getObjectType() {
            return null;
        }
        @Override
        public String identify() {
            return null;
        }
        @Override
        public String identifySimple() {
            return null;
        }
        @Override
        public ObjectTag setPrefix(String prefix) {
            return null;
        }
        @Override
        public ObjectTag getObjectAttribute(Attribute attribute) {
            if (!attribute.hasAlternative()) {
                Debug.echoDebug(attribute.getScriptEntry(), "Unfilled attributes '" + attribute.unfilledString() +
                        "' for tag <" + attribute.getOrigin() + ">!");
                if (attribute.seemingSuccesses.size() > 0) {
                    String almost = attribute.seemingSuccesses.get(attribute.seemingSuccesses.size() - 1);
                    if (attribute.hasContextFailed) {
                        Debug.echoDebug(attribute.getScriptEntry(), "Almost matched but failed (missing [context] parameter?): " + almost);
                    }
                    else {
                        Debug.echoDebug(attribute.getScriptEntry(), "Almost matched but failed (possibly bad input?): " + almost);
                    }
                }
            }
            if (Debug.verbose) {
                Debug.log("Element - Unfilled! Null!");
            }
            return null;
        }
    }

    public ObjectTag getNextObjectTypeDown() {
        return new FailedObjectTag();
    }
}