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package Runner;
use Mo;
has args => [];
has callback => ();
sub run {
my ($self, $calc) = @_;
$self->callback($calc);
return $self->run_file if @{$self->{args}};
while (1) {
print "\nEnter an equation: ";
my $expr = <> || '';
chomp $expr;
last unless length $expr;
$self->calc($expr);
}
}
sub run_file {
my ($self) = @_;
my $file = shift(@{$self->args});
open IN, "<", $file or die "Can't open '$file' for input";
while (<IN>) {
next if /^(?:#|$)/;
chomp;
$self->calc($_);
}
}
sub calc {
my ($self, $expr) = @_;
my $result = eval { $self->callback->($expr) };
if ($@) {
warn $@;
return;
}
print "$expr = $result\n";
# Double-check answer:
$expr =~ s/\^/**/g;
$expr =~ s/--/- -/g;
my $want = eval $expr;
print " EXPECTED $want\n"
if $result ne $want;
}
1;
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