Why did you convert the "+"s to "*"s? That slows things down greatly (24% for $short, 74% for $long).

               Rate   triple-s  triple-sp
triple-s   122303/s         --       -24%
triple-sp  160627/s        31%         --

              Rate   triple-s  triple-sp
triple-s    2337/s         --       -74%
triple-sp   8991/s       285%         --
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That surprised me, honestly. I only expected it to help when there were no leading/trailing spaces.