An implementation of the Substitution interface. Performs substitutions in accordance with Perl-like substitution scripts.
The latter is a string, containing a mix of memory register references and plain text blocks.
It may look like "some_chars $1 some_chars$2some_chars" or "123${1}45${2}67".
A tag consisting of '$',not preceeded by the escape character'\' and followed by some digits (possibly enclosed in the curled brackets) is interpreted as a memory register reference, the digits forming a register ID.
All the rest is considered as a plain text.
Upon the Replacer has found a text block that matches the pattern, a references in a replacement string are replaced by the contents of
corresponding memory registers, and the resulting text replaces the matched block.
For example, the following code:
System.out.println("\""+
new Replacer(new Pattern("\\b(\\d+)\\b"),new PerlSubstitution("'$1'")).replace("abc 123 def")
+"\"");
will print
"abc '123' def".