Yes the wording is odd, but like a lot of perl docs, if you keep reading you will get all the details, like: A second e modifier will cause the replacement portion to be evaled before being run as a Perl expression.

I once wrote

s/regex/STRING /e

means replace that matched by regex with string

s/regex/CODEHERE/e

means replace that matched by regex with result of code; the e in s///e tells the s///ubstitution operator that the s//CODEHERE/e is code and not a string

s/regex/CODEHERE/e

means treat CODEHERE string as code

s/regex/CODEHERE/ee

means treat CODEHERE string as code, and treat the return value of that code as code

s/regex/CODEHERE/ee

means s/regex/eval CODEHERE/e

One time I even tried to explain this way :)

my $string = 'string';
## s/string/replacement/;
$string->substitute( 'pattern', 'replacement' );
## s/string/codehere/e;
$string->substitute( 'pattern', sub { ... } );
## s/string/codehere/ee;
$string->substitute( 'pattern', sub { eval ... } );
## s/string/codehere/eee;
$string->substitute( 'pattern', sub { eval eval ... } );
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