I was testing some code when it struck me that I'm doing some work
which the compiler can easily do: commenting out and uncommenting
logical blocks of code.

Anonymous blocks, if/else, switch, for/while, struct/class, and whole
functions could be commented out by marking them on one line, without
the user having to scroll and find the logical end.

e.g. (proposal using "//**", but it could be something else)


   //**for(int i=0, i<length; ++i)
   {
     // stuff ...
   }


No need to put anything after the closing brace. Nothing
revolutionary, but saves a bit of tedious navigation, and I think it
wouldn't be very hard for a compiler hacker.

RFC, & thanks for reading.

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On 26 ene, 23:09, rk <rational.lamp...@gmail.com> wrote:

Well, the problem is that in order to know where the block ends, it
has to have a mostly correct structure.
If the syntax is correct you may easily disable it adding "if (0)"

e.g.

if (0) for(int i=0, i<length; ++i)
    {
      // stuff ...
    }

That does nothing!

Regards.
Rodrigo.

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On Jan 26, 4:09 pm, rk <rational.lamp...@gmail.com> wrote:
> I was testing some code when it struck me that I'm doing some work
> which the compiler can easily do: commenting out and uncommenting
> logical blocks of code.
>
> Anonymous blocks, if/else, switch, for/while, struct/class, and whole
> functions could be commented out by marking them on one line, without
> the user having to scroll and find the logical end.
>
> e.g. (proposal using "//**", but it could be something else)
>
>    //**for(int i=0, i<length; ++i)
>    {
>      // stuff ...
>    }
>
> No need to put anything after the closing brace. Nothing
> revolutionary, but saves a bit of tedious navigation, and I think it
> wouldn't be very hard for a compiler hacker.

As mentioned before, the if (0) prefix approach will work for the
simple cases (I haven't checked for corner cases where it would cause
a syntax error).

I'm having problems visualizing how to implement this type of
comment.  (Comments are whitespace, so this is a preprocessor
adjustment rather than a compiler adjustment.)  Consider this toy
example

#if 1
//**for(int i=0, i<length; ++i)
{
#else
for(int i=0, i<length-1; ++i)
{
#endif
}

Comment flushing to whitespace happens before conditional
preprocessing in reasonably standard-compliant preprocessors, so if
the source code is otherwise correct this will comment out the entire
file past the start of the comment.  [/* */ comments don't have this
problem because they explicitly do not try to nest: /* /* */ still
terminates at */ .  Brace blocks {} do nest.]

By comparison,

#if 1
//**for(int i=0, i<length; ++i)
#else
for(int i=0, i<length-1; ++i)
#endif
{
}

looks like it should terminate (assuming that the new comment format
picks up on the {} at all, instead of being malformed by the #else.)


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On Jan 27, 9:02 pm, Rodrigo <rodrigorivasco...@gmail.com> wrote:
> On 26 ene, 23:09, rk <rational.lamp...@gmail.com> wrote:
>
> Well, the problem is that in order to know where the block ends, it
> has to have a mostly correct structure.
> If the syntax is correct you may easily disable it adding "if (0)"
>
> e.g.
>
> if (0) for(int i=0, i<length; ++i)
>     {
>       // stuff ...
>     }
>
> That does nothing!
>
> Regards.
> Rodrigo.

Yes, the structure would be mostly correct (may not be compilable or
link) but would have the closing brace where required. The if(0) works
in the example I gave, but not on anything global like functions or
classes.

As for the preprocessor issue brought up by Kenneth 'Bessarion' Boyd,
I don't really see the point in using this comment mark if you're
already using macros to conditionally discard entire blocks. An #if
1 ... #endif  around the for loop would suffice.

Thanks


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