# Benchmark:                                                                                    
# Timing 10000 iterations of x, xr, xrs...                                                      
#         x: 0.469 wallclock secs (0.468 usr 0.005 sys 0.472 cpu) @ 21309.558/s (n=10000)       
#         xr: 0.964 wallclock secs (0.977 usr 0.005 sys 0.982 cpu) @ 10375.392/s (n=10000)      
#        xrs: 1.729 wallclock secs (1.752 usr 0.006 sys 1.759 cpu) @ 5782.135/s (n=10000)       
# O-----O---------O------O------O------O                                                        
# |     | Rate    | x    | xr   | xrs  |                                                        
# O=====O=========O======O======O======O                                                        
# | x   | 21310/s | --   | -61% | -80% |                                                        
# | xr  | 10375/s | 155% | --   | -49% |                                                        
# | xrs | 5782/s  | 396% | 94%  | --   |                                                        
# O-----O---------O------O------O------O                                                        
role XR[$cap] {                                                                                 
  has Int @!x;                                                                                  
  method set($i, $v) { @!x[$i] = $v; }                                                          
};                                                                                              
role XRS[$cap] {                                                                                
  has Int @!x[$cap];                                                                            
  method set($i, $v) { @!x[$i] = $v; }                                                          
};                                                                                              
class X {                                                                                       
  has $!cap is built;                                                                           
  has Int @!x;                                                                                  
  method TWEAK { @!x = Nil xx $!cap }                                                           
  method set($i, $v) { @!x[$i] = $v; }                                                          
}                                                                                               
use Bench;                                                                                      
for (50, 10000) -> $iters { # warmup                                                            
  my $b = Bench.new;                                                                            
  $b.cmpthese($iters, {                                                                         
    x => {                                                                                      
      my $x = X.new(cap => 100);                                                                
      for ^100 { $x.set($_, 42) };                                                              
    },                                                                                          
    xr => {                                                                                     
      my $x = XR[100].new();                                                                    
      for ^100 { $x.set($_, 42) };                                                              
    },                                                                                          
    xrs => {                                                                                    
      my $x = XRS[100].new();                                                                   
      for ^100 { $x.set($_, 42) };                                                              
    },                                                                                          
  });                                                                                           
}