Server IP : 85.214.239.14 / Your IP : 3.138.34.93 Web Server : Apache/2.4.62 (Debian) System : Linux h2886529.stratoserver.net 4.9.0 #1 SMP Tue Jan 9 19:45:01 MSK 2024 x86_64 User : www-data ( 33) PHP Version : 7.4.18 Disable Function : pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wifcontinued,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_get_handler,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,pcntl_async_signals,pcntl_unshare, MySQL : OFF | cURL : OFF | WGET : ON | Perl : ON | Python : ON | Sudo : ON | Pkexec : OFF Directory : /proc/2/root/usr/share/doc/libparse-recdescent-perl/examples/ |
Upload File : |
#!/usr/bin/perl -sw # RPN ARITHMETIC EXPRESSIONS use Parse::RecDescent; sub Parse::RecDescent::rpn { my @list = @_; for (my $i=1; $i<@list; $i+=2) { @list[$i,$i+1] = @list[$i+1,$i]; } join " ", @list; } # $RD_TRACE=1; $grammar = q{ expr : <leftop: conj /(\|\|)/ conj> { rpn(@{$item[1]}) } conj : <leftop: addn /(&&)/ addn> { rpn(@{$item[1]}) } addn : <leftop: mult /([+-])/ mult > { rpn(@{$item[1]}) } mult : <leftop: expo /([*\/\%])/ expo > { rpn(@{$item[1]}) } expo : <leftop: unary /(\^|\*\*)/ unary > { rpn(@{$item[1]}) } unary : '(' expr ')' { $item[2] } | value value : /\d+(\.\d+)?/ }; $parse = new Parse::RecDescent ($grammar) or die "bad grammar"; while (<>) { print $parse->expr($_), "\n" if $_; }