#－－－souce code －－－
###-Usage-: perl _perl.PL 2>/dev/null ###
#!perl
use feature qw(say);
### CONFIG AREA ###
my $MAX = 8; # permutation num ;
####### END #######
my @a=qw();
my $len_a=$MAX*2-1;
my $file_header='
#!perl
use feature qw(say);
#--- TEST ---
my $loc_i=0;
my $MAX='."$MAX".'; # the num you want to make the
my @arr_loc=qw();
#---start permutation
';
my $for_header='for(@arr_loc[$loc_i]=0;@arr_loc[$loc_i]<$MAX; @arr_loc[$loc_i]++){ next if $arr_loc[$loc_i] ~~ @arr_loc[0..$loc_i-1]; $loc_i++; #---;
'x ($MAX-1);
my $say_kernel=' for(@arr_loc[$loc_i]=0;@arr_loc[$loc_i]<$MAX; @arr_loc[$loc_i]++){ next if $arr_loc[$loc_i] ~~ @arr_loc[0..$loc_i-1]; say @arr_loc ; }#end
' ;
my $for_tail='$loc_i--; } #end for
' x ($MAX-1) ;
open FP, '>', "bak.perl.PL";
select FP;
say "$file_header","$for_header\n","$say_kernel\n","$for_tail";
close FP;
select STDOUT;
my @perl_cml=qw(perl bak.perl.PL);
open STDERR, ">",'/dev/null';
system(@perl_cml);
close STDERR;
`rm bak.perl.PL`;