``````package PPI::Token::Number;

=pod

PPI::Token::Number - Token class for a number

\$n = 1234;       # decimal integer
\$n = 0b1110011;  # binary integer
\$n = 01234;      # octal integer
\$n = 0x1234;     # hexadecimal integer
\$n = 12.34e-56;  # exponential notation ( currently not working )

PPI::Token::Number
isa PPI::Token
isa PPI::Element

The C<PPI::Token::Number> class is used for tokens that represent numbers,
in the various types that Perl supports.

=cut

use strict;
use PPI::Token ();

our \$VERSION = '1.276';

our @ISA = "PPI::Token";

=pod

The C<base> method is provided by all of the ::Number subclasses.
This is 10 for decimal, 16 for hexadecimal, 2 for binary, etc.

=cut

sub base() { 10 }

=pod

Return the numeric value of this token.

=cut

sub literal {
return 0 + \$_[0]->_literal;
}

sub _literal {
# De-sugar the string representation
my \$self   = shift;
my \$string = \$self->content;
\$string =~ s/^\+//;
\$string =~ s/_//g;
return \$string;
}

#####################################################################
# Tokenizer Methods

sub __TOKENIZER__on_char {
my \$class = shift;
my \$t     = shift;
my \$char  = substr( \$t->{line}, \$t->{line_cursor}, 1 );

# Allow underscores straight through
return 1 if \$char eq '_';

# Handle the conversion from an unknown to known type.
# The regex covers "potential" hex/bin/octal number.
my \$token = \$t->{token};
if ( \$token->{content} =~ /^-?0_*\$/ ) {
# This could be special
if ( \$char eq 'x' || \$char eq 'X' ) {
\$t->{class} = \$t->{token}->set_class( 'Number::Hex' );
return 1;
} elsif ( \$char eq 'b' || \$char eq 'B' ) {
\$t->{class} = \$t->{token}->set_class( 'Number::Binary' );
return 1;
} elsif ( \$char =~ /\d/ ) {
# You cannot have 8s and 9s on octals
if ( \$char eq '8' or \$char eq '9' ) {
\$token->{_error} = "Illegal character in octal number '\$char'";
}
\$t->{class} = \$t->{token}->set_class( 'Number::Octal' );
return 1;
}
}

# Handle the easy case, integer or real.
return 1 if \$char =~ /\d/o;

if ( \$char eq '.' ) {
\$t->{class} = \$t->{token}->set_class( 'Number::Float' );
return 1;
}
if ( \$char eq 'e' || \$char eq 'E' ) {
\$t->{class} = \$t->{token}->set_class( 'Number::Exp' );
return 1;
}

# Doesn't fit a special case, or is after the end of the token
# End of token.
\$t->_finalize_token->__TOKENIZER__on_char( \$t );
}

1;

=pod

Compared to Perl, the number tokenizer is too liberal about allowing
underscores anywhere.  For example, the following is a syntax error in
Perl, but is allowed in PPI:

0_b10

- Treat v-strings as binary strings or barewords, not as "base-256"
numbers

- Break out decimal integers into their own subclass?

- Implement literal()

See the L<support section|PPI/SUPPORT> in the main module.