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Merge pull request #2851 from akosthekiss/doc-charset-hyphen-escape 

Be more precise in documentation of char set when escaping is needed
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Terence Parr 2020-11-24 10:17:28 -08:00 committed by GitHub
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doc/lexer-rules.md
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@ -58,7 +58,7 @@ Match that character or sequence of characters. E.g., ’while’ or ’=’.</t
<tr>
<td>[char set]</td><td>
<p>Match one of the characters specified in the character set. Interpret <tt>x-y</tt> as the set of characters between range <tt>x</tt> and <tt>y</tt>, inclusively. The following escaped characters are interpreted as single special characters: <tt>\n</tt>, <tt>\r</tt>, <tt>\b</tt>, <tt>\t</tt>, <tt>\f</tt>, <tt>\uXXXX</tt>, and <tt>\u{XXXXXX}</tt>. To get <tt>]</tt>, <tt>\</tt>, or <tt>-</tt> you must escape them with <tt>\</tt>.</p>
<p>Match one of the characters specified in the character set. Interpret <tt>x-y</tt> as the set of characters between range <tt>x</tt> and <tt>y</tt>, inclusively. The following escaped characters are interpreted as single special characters: <tt>\n</tt>, <tt>\r</tt>, <tt>\b</tt>, <tt>\t</tt>, <tt>\f</tt>, <tt>\uXXXX</tt>, and <tt>\u{XXXXXX}</tt>. To get <tt>]</tt> or <tt>\</tt> you must escape them with <tt>\</tt>. To get <tt>-</tt> you must escape it with <tt>\</tt> too, except for the case when <tt>-</tt> is the first or last character in the set.</p>
<p>You can also include all characters matching Unicode properties (general category, boolean, or enumerated including scripts and blocks) with <tt>\p{PropertyName}</tt> or <tt>\p{EnumProperty=Value}</tt>. (You can invert the test with <tt>\P{PropertyName}</tt> or <tt>\P{EnumProperty=Value}</tt>).</p>
@ -90,6 +90,8 @@ UNICODE_ID : [\p{Alpha}\p{General_Category=Other_Letter}] [\p{Alnum}\p{General_C
EMOJI : [\u{1F4A9}\u{1F926}] ; // note Unicode code points > U+FFFF
DASHBRACK : [\-\]]+ ; // match - or ] one or more times
DASH : [---] ; // match a single -, i.e., "any character" between - and - (note first and last - not escaped)
</pre>
</td>
</tr>