Re: Mutability of loop variables

[Araq]

In this case it's best to introduce a new `let` binding. This way you shadow 
the `for` loop variable so there is no way to accidentically refer to it:
    
    
    import strutils
    
    let s = "a \n b\n c \n"
    
    for line in s.splitLines:
        let line = line.strip
        # TODO further procession of line