[lifthrasiir]

Probably you should first consider that our browsers contain a fully capable programming system which this golfed program abuses as an expression evaluator. :-) By comparison, this C program [1] (hints are at [2]) is a stripped down spreadsheet program for X, and it only has an RPN evaluator (probably to make a room for graphing features?).

[1] http://www.ioccc.org/2000/jarijyrki.c

[2] http://www.ioccc.org/2000/jarijyrki.hint

[vidarh]

Hilariously Chrome offers to pass the c code through Google Translate (with predictably useless results)

[ajnin]

Amusingly it detects that the code for the RPN calculator is in Polish. Maybe it's smarter than it seems.

[dannyw]

Language detection works on language trigrams, and are trained on human language. I bet punctuation is stripped during preprocessing. So it's not surprising that code will have false positives.

[vidarh]

Not surprising, but still funny when applied to obfuscated code.