Main sections of KatePart Highlight Definition files

A highlighting file contains a header that sets the XML version:

<?xml version="1.0" encoding="UTF-8"?>

The root of the definition file is the element language. Available attributes are:

Required attributes:

name sets the name of the language. It appears in the menus and dialogs afterwards.

section specifies the category.

extensions defines file extensions, such as "*.cpp;*.h"

version specifies the current revision of the definition file in terms of an integer number. Whenever you change a highlighting definition file, make sure to increase this number.

kateversion specifies the latest supported KatePart version.

Optional attributes:

mimetype associates files MIME type.

casesensitive defines, whether the keywords are case sensitive or not.

priority is necessary if another highlight definition file uses the same extensions. The higher priority will win.

author contains the name of the author and his email-address.

license contains the license, usually the MIT license for new syntax-highlighting files.

style contains the provided language and is used by the indenters for the attribute required-syntax-style.

indenter defines which indenter will be used by default. Available indenters are: ada, normal, cstyle, cmake, haskell, latex, lilypond, lisp, lua, pascal, python, replicode, ruby and xml.

hidden defines whether the name should appear in KatePart's menus.

So the next line may look like this:

<language name="C++" version="1" kateversion="2.4" section="Sources" extensions="*.cpp;*.h" />

Next comes the highlighting element, which contains the optional element list and the required elements contexts and itemDatas.

list elements contain a list of keywords. In this case the keywords are class and const. You can add as many lists as you need.

Since KDE Frameworks™ 5.53, a list can include keywords from another list or language/file, using the include element. ## is used to separate the list name and the language definition name, in the same way as in the IncludeRules rule. This is useful to avoid duplicating keyword lists, if you need to include the keywords of another language/file. For example, the othername list contains the str keyword and all the keywords of the types list, which belongs to the ISO C++ language.

The contexts element contains all contexts. The first context is by default the start of the highlighting. There are two rules in the context Normal Text, which match the list of keywords with the name somename and a rule that detects a quote and switches the context to string. To learn more about rules read the next chapter.

The third part is the itemDatas element. It contains all color and font styles needed by the contexts and rules. In this example, the itemData Normal Text, String and Keyword are used.

  <highlighting>
    <list name="somename">
      <item>class</item>
      <item>const</item>
    </list>
    <list name="othername">
      <item>str</item>
      <include>types##ISO C++</include>
    </list>
    <contexts>
      <context attribute="Normal Text" lineEndContext="#pop" name="Normal Text" >
        <keyword attribute="Keyword" context="#stay" String="somename" />
        <keyword attribute="Keyword" context="#stay" String="othername" />
        <DetectChar attribute="String" context="string" char="&quot;" />
      </context>
      <context attribute="String" lineEndContext="#stay" name="string" >
        <DetectChar attribute="String" context="#pop" char="&quot;" />
      </context>
    </contexts>
    <itemDatas>
      <itemData name="Normal Text" defStyleNum="dsNormal" />
      <itemData name="Keyword" defStyleNum="dsKeyword" />
      <itemData name="String" defStyleNum="dsString" />
    </itemDatas>
  </highlighting>

The last part of a highlight definition is the optional general section. It may contain information about keywords, code folding, comments, indentation, empty lines and spell checking.

The comment section defines with what string a single line comment is introduced. You also can define a multiline comment using multiLine with the additional attribute end. This is used if the user presses the corresponding shortcut for comment/uncomment.

The keywords section defines whether keyword lists are case sensitive or not. Other attributes will be explained later.

The other sections, folding, emptyLines and spellchecking, are usually not necessary and are explained later.

  <general>
    <comments>
      <comment name="singleLine" start="#"/>
      <comment name="multiLine" start="###" end="###" region="CommentFolding"/>
    </comments>
    <keywords casesensitive="1"/>
    <folding indentationsensitive="0"/>
    <emptyLines>
      <emptyLine regexpr="\s+"/>
      <emptyLine regexpr="\s*#.*"/>
    </emptyLines>
    <spellchecking>
      <encoding char="á" string="\'a"/>
      <encoding char="à" string="\`a"/>
    </spellchecking>
  </general>
</language>

The element context belongs in the group contexts. A context itself defines context specific rules such as what should happen if the highlight system reaches the end of a line. Available attributes are:

name states the context name. Rules will use this name to specify the context to switch to if the rule matches.

lineEndContext defines the context the highlight system switches to if it reaches the end of a line. This may either be a name of another context, #stay to not switch the context (e.g.. do nothing) or #pop which will cause it to leave this context. It is possible to use for example #pop#pop#pop to pop three times, or even #pop#pop!OtherContext to pop two times and switch to the context named OtherContext. It is also possible to switch to a context that belongs to another language definition, in the same way as in the IncludeRules rules, e.g., SomeContext##JavaScript. Note that it is not possible to use this context switch in combination with #pop, for example, #pop!SomeContext##JavaScript is not valid. Context switches are also described in the section called “Highlight Detection Rules”.

lineEmptyContext defines the context if an empty line is encountered. The nomenclature of context switches is the same as previously described in lineEndContext. Default: #stay.

fallthroughContext specifies the next context to switch to if no rule matches. The nomenclature of context switches is the same as previously described in lineEndContext. Default: #stay.

fallthrough defines if the highlight system switches to the context specified in fallthroughContext if no rule matches. Note that since KDE Frameworks™ 5.62 this attribute is deprecated in favor of fallthroughContext, since if the fallthroughContext attribute is present it is implicitly understood that the value of fallthrough is true. Default: false.

noIndentationBasedFolding disables indentation-based folding in the context. If indentation-based folding is not activated, this attribute is useless. This is defined in the element folding of the group general. Default: false.

The element itemData is in the group itemDatas. It defines the font style and colors. So it is possible to define your own styles and colors. However, we recommend you stick to the default styles if possible so that the user will always see the same colors used in different languages. Though, sometimes there is no other way and it is necessary to change color and font attributes. The attributes name and defStyleNum are required, the others are optional. Available attributes are:

name sets the name of the itemData. Contexts and rules will use this name in their attribute attribute to reference an itemData.

defStyleNum defines which default style to use. Available default styles are explained in detail later.

color defines a color. Valid formats are '#rrggbb' or '#rgb'.

selColor defines the selection color.

italic if true, the text will be italic.

bold if true, the text will be bold.

underline if true, the text will be underlined.

strikeout if true, the text will be struck out.

spellChecking if true, the text will be spellchecked.

The element keywords in the group general defines keyword properties. Available attributes are:

casesensitive may be true or false. If true, all keywords are matched case sensitively.

weakDeliminator is a list of characters that do not act as word delimiters. For example, the dot '.' is a word delimiter. Assume a keyword in a list contains a dot, it will only match if you specify the dot as a weak delimiter.

additionalDeliminator defines additional delimiters.

wordWrapDeliminator defines characters after which a line wrap may occur.

Default delimiters and word wrap delimiters are the characters .():!+,-<=>%&*/;?[]^{|}~\, space (' ') and tabulator ('\t').

The element comment in the group comments defines comment properties which are used for Tools → Comment, Tools → Uncomment and Tools → Toggle Comment. Available attributes are:

name is either singleLine or multiLine. If you choose multiLine the attributes end and region are required. If you choose singleLine you can add the optional attribute position.

start defines the string used to start a comment. In C++ this would be "/*" in multiline comments. This attribute is required for types multiLine and singleLine.

end defines the string used to close a comment. In C++ this would be "*/". This attribute is only available and is required for comments of type multiLine.

region should be the name of the foldable multiline comment. Assume you have beginRegion="Comment" ... endRegion="Comment" in your rules, you should use region="Comment". This way uncomment works even if you do not select all the text of the multiline comment. The cursor only must be in the multiline comment. This attribute is only available for type multiLine.

position defines where the single line comment is inserted. By default, the single line comment is placed at the beginning of the line at column 0, but if you use position="afterwhitespace" the comment is inserted after leading whitespaces right, before the first non-whitespace character. This is useful for putting comments correctly in languages where indentation is important, such as Python or YAML. This attribute is optional and the only possible value is afterwhitespace. This is only available for type singleLine.

The element folding in the group general defines code folding properties. Available attributes are:

indentationsensitive if true, the code folding markers will be added indentation based, as in the scripting language Python. Usually you do not need to set it, as it defaults to false.

The element emptyLine in the group emptyLines defines which lines should be treated as empty lines. This allows modifying the behavior of the lineEmptyContext attribute in the elements context. Available attributes are:

regexpr defines a regular expression that will be treated as an empty line. By default, empty lines do not contain any characters, therefore, this adds additional empty lines, for example, if you want lines with spaces to also be considered empty lines. However, in most syntax definitions you do not need to set this attribute.

The element encoding in the group spellchecking defines a character encoding for spell checking. Available attributes:

char is a encoded character.

string is a sequence of characters that will be encoded as the character char in the spell checking. For example, in the language LaTeX, the string \"{A} represents the character Ä.

General default styles:

dsNormal, when no special highlighting is required.

dsKeyword, built-in language keywords.

dsFunction, function calls and definitions.

dsVariable, if applicable: variable names (e.g. $someVar in PHP/Perl).

dsControlFlow, control flow keywords like if, else, switch, break, return, yield, ...

dsOperator, operators like + - * / :: < >

dsBuiltIn, built-in functions, classes, and objects.

dsExtension, common extensions, such as Qt™ classes and functions/macros in C++ and Python.

dsPreprocessor, preprocessor statements or macro definitions.

dsAttribute, annotations such as @override and __declspec(...).

String-related default styles:

dsChar, single characters, such as 'x'.

dsSpecialChar, chars with special meaning in strings such as escapes, substitutions, or regex operators.

dsString, strings like "hello world".

dsVerbatimString, verbatim or raw strings like 'raw \backlash' in Perl, CoffeeScript, and shells, as well as r'\raw' in Python.

dsSpecialString, SQL, regexes, HERE docs, L^AT_EX math mode, ...

dsImport, import, include, require of modules.

Number-related default styles:

dsDataType, built-in data types like int, void, u64.

dsDecVal, decimal values.

dsBaseN, values with a base other than 10.

dsFloat, floating point values.

dsConstant, built-in and user defined constants like PI.

Comment and documentation-related default styles:

dsComment, comments.

dsDocumentation, /** Documentation comments */ or """docstrings""".

dsAnnotation, documentation commands like @param, @brief.

dsCommentVar, the variable names used in above commands, like "foobar" in @param foobar.

dsRegionMarker, region markers like //BEGIN, //END in comments.

Other default styles:

dsInformation, notes and tips like @note in doxygen.

dsWarning, warnings like @warning in doxygen.

dsAlert, special words like TODO, FIXME, XXXX.

dsError, error highlighting and wrong syntax.

dsOthers, when nothing else fits.

DetectChar

Detect a single specific character. Commonly used for example to find the ends of quoted strings.

<DetectChar char="(character)" (common attributes) (dynamic) />

The char attribute defines the character to match.

Detect2Chars

Detect two specific characters in a defined order.

<Detect2Chars char="(character)" char1="(character)" (common attributes) />

The char attribute defines the first character to match, char1 the second.

AnyChar

Detect one character of a set of specified characters.

<AnyChar String="(string)" (common attributes) />

The String attribute defines the set of characters.

StringDetect

Detect an exact string.

<StringDetect String="(string)" [insensitive="true|false"] (common attributes) (dynamic) />

The String attribute defines the string to match. The insensitive attribute defaults to false and is passed to the string comparison function. If the value is true insensitive comparing is used.

WordDetect

Detect an exact string but additionally require word boundaries such as a dot '.' or a whitespace on the beginning and the end of the word. Think of \b<string>\b in terms of a regular expression, but it is faster than the rule RegExpr.

<WordDetect String="(string)" [insensitive="true|false"] (common attributes) (local deliminators) />

The String attribute defines the string to match. The insensitive attribute defaults to false and is passed to the string comparison function. If the value is true insensitive comparing is used.

Since: Kate 3.5 (KDE 4.5)

RegExpr

Matches against a regular expression.

<RegExpr String="(string)" [insensitive="true|false"] [minimal="true|false"] (common attributes) (dynamic) />

The String attribute defines the regular expression.

insensitive defaults to false and is passed to the regular expression engine.

minimal defaults to false and is passed to the regular expression engine.

Because the rules are always matched against the beginning of the current string, a regular expression starting with a caret (^) indicates that the rule should only be matched against the start of a line.

See Regular Expressions for more information on those.

keyword

Detect a keyword from a specified list.

<keyword String="(list name)" (common attributes) (local deliminators) />

The String attribute identifies the keyword list by name. A list with that name must exist.

The highlighting system processes keyword rules in a very optimized way. This makes it an absolute necessity that any keywords to be matched need to be surrounded by defined delimiters, either implied (the default delimiters), or explicitly specified within the additionalDeliminator property of the keywords tag.

If a keyword to be matched shall contain a delimiter character, this respective character must be added to the weakDeliminator property of the keywords tag. This character will then loose its delimiter property in all keyword rules. It is also possible to use the weakDeliminator attribute of keyword so that this modification only applies to this rule.

Int

Detect an integer number (as the regular expression: \b[0-9]+).

<Int (common attributes) (local deliminators) />

This rule has no specific attributes.

Float

Detect a floating point number (as the regular expression: (\b[0-9]+\.[0-9]*|\.[0-9]+)([eE][-+]?[0-9]+)?).

<Float (common attributes) (local deliminators) />

This rule has no specific attributes.

HlCOct

Detect an octal point number representation (as the regular expression: \b0[0-7]+).

<HlCOct (common attributes) (local deliminators) />

This rule has no specific attributes.

HlCHex

Detect a hexadecimal number representation (as a regular expression: \b0[xX][0-9a-fA-F]+).

<HlCHex (common attributes) (local deliminators) />

This rule has no specific attributes.

HlCStringChar

Detect an escaped character.

<HlCStringChar (common attributes) />

This rule has no specific attributes.

It matches literal representations of characters commonly used in program code, for example \n (newline) or \t (TAB).

The following characters will match if they follow a backslash (\): abefnrtv"'?\. Additionally, escaped hexadecimal numbers such as for example \xff and escaped octal numbers, for example \033 will match.

HlCChar

Detect an C character.

<HlCChar (common attributes) />

This rule has no specific attributes.

It matches C characters enclosed in a tick (Example: 'c'). The ticks may be a simple character or an escaped character. See HlCStringChar for matched escaped character sequences.

RangeDetect

Detect a string with defined start and end characters.

<RangeDetect char="(character)"  char1="(character)" (common attributes) />

char defines the character starting the range, char1 the character ending the range.

Useful to detect for example small quoted strings and the like, but note that since the highlighting engine works on one line at a time, this will not find strings spanning over a line break.

LineContinue

Matches a specified char at the end of a line.

<LineContinue (common attributes) [char="\"] />

char optional character to match, default is backslash ('\'). New since KDE 4.13.

This rule is useful for switching context at end of line. This is needed for example in C/C++ to continue macros or strings.

IncludeRules

Include rules from another context or language/file.

<IncludeRules context="contextlink" [includeAttrib="true|false"] />

The context attribute defines which context to include.

If it is a simple string it includes all defined rules into the current context, example:

<IncludeRules context="anotherContext" />

If the string contains a ## the highlight system will look for a context from another language definition with the given name, for example

<IncludeRules context="String##C++" />

would include the context String from the C++ highlighting definition.

If includeAttrib attribute is true, change the destination attribute to the one of the source. This is required to make, for example, commenting work, if text matched by the included context is a different highlight from the host context.

DetectSpaces

Detect whitespaces.

<DetectSpaces (common attributes) />

This rule has no specific attributes.

Use this rule if you know that there can be several whitespaces ahead, for example in the beginning of indented lines. This rule will skip all whitespace at once, instead of testing multiple rules and skipping one at a time due to no match.

DetectIdentifier

Detect identifier strings (as the regular expression: [a-zA-Z_][a-zA-Z0-9_]*).

<DetectIdentifier (common attributes) />

This rule has no specific attributes.

Use this rule to skip a string of word characters at once, rather than testing with multiple rules and skipping one at a time due to no match.