[BREAKING CHANGES] Rename Ok,Err and Remove :Result attribute and more.

[kfly8]

This pull requests produces these things:

1. Rename Ok,Err to ok,err
2. Remove :Result attribute, Added result_for function
3. Use @EXPORT_OK to export ok, err and result_for
4. Change default value of $ENV{RESULT_SIMPLE_CHECK_ENABLED}
5. Added unsafe_unwrap, unsafe_unwrap_err
6. Added alias features

1. Rename Ok,Err to ok,err

I think Ok and Err does not align perl conventions. In perl, we usually use snake case. So I renamed function names.

2. Remove :Result attribute, Added result_for function

It is hard to control attribute and it has bugs like this:

use Result::Simple qw(ok err); # => It fails to import :Result attribute

So, I added result_for function, it is simple wrapper for function:

result_for div => Int, ErrorMessage;

sub div {
   my ($x, $y) = @_;
   if ($y == 0) {
      return err("Division by zero");
   }
  return ok ($x / $y);
}

3. Use @EXPORT_OK to export ok, err and result_for

It would be better to specify which functions are to be imported.

4. Change default value of $ENV{RESULT_SIMPLE_CHECK_ENABLED}

Changed to check values by default. Whatever the initial value, it is better to specify this environment variable in the production environment to prevent unexpected accidents.

5. Added unsafe_unwrap, unsafe_unwrap_err

These are utility test functions.

6. Added alias features

use Result::Simple 
   ok => { -as => 'left' },
   err => { -as => 'right' };

[coveralls]

Pull Request Test Coverage Report for Build 14531989382

Details

• 32 of 32 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 12041917785:	0.0%
Covered Lines:	78
Relevant Lines:	78

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💛 - Coveralls