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  1. <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>The RULES Tag</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2"><link rel="start" href="index.html" title="jEdit 4.3 User's Guide"><link rel="up" href="writing-modes.html" title="Chapter 10. Mode Definition Syntax"><link rel="prev" href="mode-tag-props.html" title="The PROPS Tag"><link rel="next" href="mode-rule-terminate.html" title="The TERMINATE Tag"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">The RULES Tag</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="mode-tag-props.html">Prev</a> </td><th width="60%" align="center">Chapter 10. Mode Definition Syntax</th><td width="20%" align="right"> <a accesskey="n" href="mode-rule-terminate.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="mode-tag-rules"></a>The RULES Tag</h2></div></div></div><p><code class="literal">RULES</code> tags must be placed inside the
    2. 

  2.         <code class="literal">MODE</code> tag. Each <code class="literal">RULES</code> tag defines a
    3. 

  3.         <em class="firstterm">ruleset</em>. A ruleset consists of a number of
    4. 

  4.         <em class="firstterm">parser rules</em>, with each parser rule specifying
    5. 

  5.         how to highlight a specific syntax token. There must be at least one
    6. 

  6.         ruleset in each edit mode. There can also be more than one, with
    7. 

  7.         different rulesets being used to highlight different parts of a buffer
    8. 

  8.         (for example, in HTML mode, one rule set highlights HTML tags, and
    9. 

  9.         another highlights inline JavaScript). For information about using more
    10. 

  10.         than one ruleset, see <a class="xref" href="mode-rule-span.html" title="The SPAN Tag">the section called &#8220;The SPAN Tag&#8221;</a>.</p><p>The <code class="literal">RULES</code> tag supports the following
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  11.         attributes, all of which are optional:</p><div class="itemizedlist"><ul type="disc"><li><p><code class="literal">SET</code> - the name of this ruleset. All
    12. 

  12.                 rulesets other than the first must have a name.</p></li><li><p><code class="literal">IGNORE_CASE</code> - if set to
    13. 

  13.                 <code class="literal">FALSE</code>, matches will be case sensitive.
    14. 

  14.                 Otherwise, case will not matter. Default is
    15. 

  15.                 <code class="literal">TRUE</code>.</p></li><li><p><code class="literal">ESCAPE</code> - specifies a character sequence
    16. 

  16.                 for escaping literals. The first character following the escape
    17. 

  17.                 sequence is not considered as input for syntax highlighting,
    18. 

  18.                 thus being highlighted with default token for the rule set.
    19. 

  19.                 </p></li><li><p><code class="literal">NO_WORD_SEP</code> - any non-alphanumeric
    20. 

  20.                 character <span class="emphasis"><em>not</em></span> in this list is treated as a
    21. 

  21.                 word separator for the purposes of syntax highlighting.</p></li><li><p><code class="literal">DEFAULT</code> - the token type for text which
    22. 

  22.                 doesn't match any specific rule. Default is
    23. 

  23.                 <code class="literal">NULL</code>. See <a class="xref" href="mode-syntax-tokens.html" title="Token Types">the section called &#8220;Token Types&#8221;</a> for a list of token
    24. 

  24.                 types.</p></li><li><p><code class="literal">HIGHLIGHT_DIGITS</code></p></li><li><p><code class="literal">DIGIT_RE</code> - see below for information
    25. 

  25.                 about these two attributes.</p></li></ul></div><p>Here is an example <code class="literal">RULES</code> tag:</p><pre class="programlisting">&lt;RULES IGNORE_CASE="FALSE" HIGHLIGHT_DIGITS="TRUE"&gt;
    26. 

  26.     <em class="replaceable"><code>... parser rules go here ...</code></em>
    27. 

  27. &lt;/RULES&gt;</pre><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2585658"></a>Highlighting Numbers</h3></div></div></div><p>If the <code class="literal">HIGHLIGHT_DIGITS</code> attribute is set to
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  28.             <code class="literal">TRUE</code>, jEdit will attempt to highlight numbers in
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  29.             this ruleset.</p><p>Any word consisting entirely of digits (0-9) will be
    30. 

  30.             highlighted with the <code class="literal">DIGIT</code> token type. A word
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  31.             that contains other letters in addition to digits will be
    32. 

  32.             highlighted with the <code class="literal">DIGIT</code> token type only if it
    33. 

  33.             matches the regular expression specified in the
    34. 

  34.             <code class="literal">DIGIT_RE</code> attribute. If this attribute is not
    35. 

  35.             specified, it will not be highlighted.</p><p>Here is an example <code class="literal">DIGIT_RE</code> regular
    36. 

  36.             expression that highlights Java-style numeric literals (normal
    37. 

  37.             numbers, hexadecimals prefixed with <code class="literal">0x</code>, numbers
    38. 

  38.             suffixed with various type indicators, and floating point literals
    39. 

  39.             containing an exponent):</p><pre class="programlisting">DIGIT_RE="(0[lL]?|[1-9]\d{0,9}(\d{0,9}[lL])?|0[xX]\p{XDigit}{1,8}(\p{XDigit}{0,8}[lL])?|0[0-7]{1,11}([0-7]{0,11}[lL])?|([0-9]+\.[0-9]*|\.[0-9]+)([eE][+-]?[0-9]+)?[fFdD]?|[0-9]+([eE][+-]?[0-9]+[fFdD]?|([eE][+-]?[0-9]+)?[fFdD]))"</pre><p>Regular expression syntax is described in <a class="xref" href="regexps.html" title="Appendix E. Regular Expressions">Appendix E, <i>Regular Expressions</i></a>.</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="rule-ordering"></a>Rule Ordering Requirements</h3></div></div></div><p>You might encounter this very common pitfall when writing your
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  40.             own modes.</p><p>Since jEdit checks buffer text against parser rules in the
    41. 

  41.             order they appear in the ruleset, more specific rules must be placed
    42. 

  42.             before generalized ones, otherwise the generalized rules will catch
    43. 

  43.             everything.</p><p>This is best demonstrated with an example. The following is
    44. 

  44.             incorrect rule ordering:</p><pre class="programlisting">&lt;SPAN TYPE="MARKUP"&gt;
    45. 

  45.     &lt;BEGIN&gt;[&lt;/BEGIN&gt;
    46. 

  46.     &lt;END&gt;]&lt;/END&gt;
    47. 

  47. &lt;/SPAN&gt;
    48. 

  48. 

  49. &lt;SPAN TYPE="KEYWORD1"&gt;
    50. 

  50.     &lt;BEGIN&gt;[!&lt;/BEGIN&gt;
    51. 

  51.     &lt;END&gt;]&lt;/END&gt;
    52. 

  52. &lt;/SPAN&gt;</pre><p>If you write the above in a rule set, any occurrence of
    53. 

  53.             &#8220;<span class="quote">[</span>&#8221; (even things like &#8220;<span class="quote">[!DEFINE</span>&#8221;, etc)
    54. 

  54.             will be highlighted using the first rule, because it will be the
    55. 

  55.             first to match. This is most likely not the intended
    56. 

  56.             behavior.</p><p>The problem can be solved by placing the more specific rule
    57. 

  57.             before the general one:</p><pre class="programlisting">&lt;SPAN TYPE="KEYWORD1"&gt;
    58. 

  58.     &lt;BEGIN&gt;[!&lt;/BEGIN&gt;
    59. 

  59.     &lt;END&gt;]&lt;/END&gt;
    60. 

  60. &lt;/SPAN&gt;
    61. 

  61. 

  62. &lt;SPAN TYPE="MARKUP"&gt;
    63. 

  63.     &lt;BEGIN&gt;[&lt;/BEGIN&gt;
    64. 

  64.     &lt;END&gt;]&lt;/END&gt;
    65. 

  65. &lt;/SPAN&gt;</pre><p>Now, if the buffer contains the text
    66. 

  66.             &#8220;<span class="quote">[!SPECIAL]</span>&#8221;, the rules will be checked in order, and
    67. 

  67.             the first rule will be the first to match. However, if you write
    68. 

  68.             &#8220;<span class="quote">[FOO]</span>&#8221;, it will be highlighted using the second rule,
    69. 

  69.             which is exactly what you would expect.</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2585828"></a>Per-Ruleset Properties</h3></div></div></div><p>The <code class="literal">PROPS</code> tag (described in <a class="xref" href="mode-tag-props.html" title="The PROPS Tag">the section called &#8220;The PROPS Tag&#8221;</a>) can also be placed inside the
    70. 

  70.             <code class="literal">RULES</code> tag to define ruleset-specific properties.
    71. 

  71.             The following properties can be set on a per-ruleset basis:</p><div class="itemizedlist"><ul type="disc"><li><p><code class="literal">commentEnd</code> - the comment end
    72. 

  72.                     string.</p></li><li><p><code class="literal">commentStart</code> - the comment start
    73. 

  73.                     string.</p></li><li><p><code class="literal">lineComment</code> - the line comment
    74. 

  74.                     string.</p></li></ul></div><p>This allows different parts of a file to have different
    75. 

  75.             comment strings (in the case of HTML, for example, in HTML text and
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  76.             inline JavaScript). For information about the commenting commands,
    77. 

  77.             see <a class="xref" href="commenting.html" title="Commenting Out Code">the section called &#8220;Commenting Out Code&#8221;</a>.</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="mode-tag-props.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="writing-modes.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="mode-rule-terminate.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">The PROPS Tag </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> The TERMINATE Tag</td></tr></table></div></body></html>
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  78.