The /e switch treats the replacement as an expression to be executed. This is not the same as evaluating the contents of $1..$n as executable code, i.e. treating the result of the interpolation as executable code, which needs "double eval" (/ee).

You could re-write 

s/(10\+4)/$1/ee;

[download]

as

s/(10\+4)/eval $1/e;

[download]

In the case of s/(10\+4)/$1/e the replacement just resolves as the code line

"10+4";

[download]

which yields a string upon execution.

update: added single /e explanation

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In reply to Re: /e in regexes by shmem
in thread /e in regexes by waldner

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