[HN Gopher] UB? In My Lexer? [pdf]
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       UB? In My Lexer? [pdf]
        
       Author : weirdsmiley
       Score  : 6 points
       Date   : 2023-06-19 18:45 UTC (4 hours ago)
        
 (HTM) web link (www.open-std.org)
 (TXT) w3m dump (www.open-std.org)
        
       | weirdsmiley wrote:
       | "UB? In my lexer?" by Corentin Jabot removes the possibility that
       | just tokenizing C++ code can be a source of undefined behavior in
       | a C++ compiler itself. (Did you know it could be UB? Now it
       | can't.) Note however that this does not remove all possible UB
       | during compilation; future papers may address more of those
       | compile-time UB sources. ~ Herb Sutter
        
       | josephcsible wrote:
       | > Further work will be needed to remove all undefined behavior in
       | [cpp].
       | 
       | The inclusion of this sentence makes me seriously question the
       | author's qualifications. Removing all UB from C++ would be a
       | terrible thing to do that would greatly slow down all C++
       | programs. If people using C++ were okay with such a slowdown,
       | they'd be using a higher-level language already instead.
        
         | valleyer wrote:
         | > The inclusion of this sentence makes me seriously question
         | the author's qualifications. Removing all UB from C++ would be
         | a terrible thing to do [...]
         | 
         | So, "[cpp]" here refers _not_ to the C++ language as a whole
         | but rather to the section of the ISO C++ standard governing the
         | behavior of the preprocessor (which is commonly referred to by
         | shorthand as  "cpp").
         | 
         | The [cpp] chapter is part of what is amended by this very
         | proposal, and part of the context that the author includes
         | shows another instance of UB in [cpp]. _That_ is what the
         | author is referring to here.
         | 
         | It's just my opinion, but your "qualifications" comment seems
         | needlessly harsh in light of that.
        
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       (page generated 2023-06-19 23:03 UTC)