So if you want the exact same semantic, it'll become far more complicated than this regex.

I agree. That's a good point. Thank you !

In other words it is not easy to design a good trim function without regex, but it is possible to design one that used regex, but treating the single quoted string as a special case

For example 

trim(' ',$line)
vs 
trim(/\s/.$line)
BTW this is impossible in Python which implements regex via library, unless you add a new lexical type to the Language (regex string instead of raw string that is used).

In reply to Re^2: How to trim a line from leading and trailing blanks without using regex or non-standard modules by likbez
in thread How to trim a line from leading and trailing blanks without using regex or non-standard modules by likbez

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