1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
use v5.10;
use warnings;
my $calculator = do{
use Regexp::Grammars;
qr{
<Answer>
<objrule: Answer>
<X=Mult> <Op=([+-])> <Y=Answer>
| <MATCH=Mult>
<objrule: Mult>
<X=Pow> <Op=([*/%])> <Y=Mult>
| <MATCH=Pow>
<objrule: Pow>
<X=Term> <Op=(\^)> <Y=Pow>
| <MATCH=Term>
<objrule: Term>
<MATCH=Literal>
| <Sign=([+-]?)> \( <Answer> \)
| \( <MATCH=Answer> \)
<objtoken: Literal>
<value=( [+-]? \d++ (?: \. \d++ )?+ )>
}xms
};
while (my $input = <>) {
my $debug = $input =~ s{^show \s+}{}xms;
if ($input =~ $calculator) {
if ($debug) {
use Data::Dumper 'Dumper';
warn Dumper \%/;
}
else {
say '--> ', $/{Answer}->eval();
}
}
}
sub Answer::eval {
my ($self) = @_;
my $x = $self->{X}->eval();
my $y = $self->{Y}->eval();
return $self->{Op} eq '+' ? $x + $y
: $x - $y;
}
sub Mult::eval {
my ($self) = @_;
my $x = $self->{X}->eval();
my $y = $self->{Y}->eval();
return $self->{Op} eq '*' ? $x * $y
: $self->{Op} eq '/' ? $x / $y
: $x % $y;
}
sub Pow::eval {
my ($self) = @_;
return $self->{X}->eval() ** $self->{Y}->eval();
}
sub Term::eval {
my ($self) = @_;
return $self->{Sign} eq '-' ? -$self->{Answer}->eval()
: $self->{Answer}->eval();
}
sub Literal::eval {
my ($self) = @_;
return $self->{value};
}
|
