Closes #50232.

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@292344 c90b9560-bf6c-de11-be94-00142212c4b1

reference/pcre/pattern.syntax.xml

@@ -26,6 +26,62 @@
       itself.  
      </para>
     </section>
+    <section xml:id="regexp.reference.delimiters">
+     <title>Delimiters</title>
+     <para>
+      When using the PCRE functions, it is required that the pattern is enclosed
+      in <emphasis>delimiters</emphasis>. A delimiter can be any non-alphanumeric,
+      non-whitespace character.
+     </para>
+     <para>
+      Often used delimiters are forward slashes (<literal>/</literal>), hash
+      signs (<literal>#</literal>) and tildes (<literal>~</literal>). The
+      following are all examples of valid delimited patterns.
+      <informalexample>
+       <programlisting>
+         /foo bar/
+         #^[^0-9]$#
+         +php+
+         %[a-zA-Z0-9_-]%
+       </programlisting>
+      </informalexample>
+     </para>
+     <para>
+      If the delimiter needs to be matched inside the pattern it will have to be
+      escaped using a backslash. If the delimiter appears often inside the
+      pattern, it is a good idea choosing another delimiter to increase
+      readability.
+      <informalexample>
+       <programlisting>
+        /http:\/\//
+        #http://#
+       </programlisting>
+      </informalexample>
+      The <function>preg_quote</function> may be used to inject a string into
+      a pattern and its second parameter allows to specify the chosen delimiter
+      so it will be escaped as well.
+     </para>
+     <para>
+      In addition to the aforementioned delimiters, it is also possible using
+      bracket style delimiters where the opening and closing brackets are the
+      starting and ending delimiter, respectively.
+      <informalexample>
+       <programlisting>
+        {this is a pattern}
+       </programlisting>
+      </informalexample>
+     </para>
+     <para>
+      You may add <link linkend="reference.pcre.pattern.modifiers">pattern
+      modifiers</link> after the ending delimiter. The following is an example
+      of case-insensitive matching:
+      <informalexample>
+       <programlisting>
+        #[a-z]#i
+       </programlisting>
+      </informalexample>
+     </para>
+    </section>
     <section xml:id="regexp.reference.meta">
      <title>Meta-characters</title>
      <para>