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package MatrixParser::Lexer;
use strict;
use warnings;
use feature qw(say signatures);
no warnings 'experimental::signatures';
use List::Util qw(none);
use MatrixParser::Token;
sub new ( $class, $input ) {
my $self = {
input => [ split( //, $input ) ],
line => 1,
pos => 0
};
return bless $self, $class;
}
sub next_token($self) {
$self->_skip_whitespace;
return if $self->_eof;
my $char = $self->_advance();
$self->_unexpected_input($char)
if none { $_ eq $char } qw(1 0 [ ]);
return MatrixParser::Token->new( $char, $self->{line}, $self->{pos} );
}
sub _skip_whitespace($self) {
return if $self->_eof;
while (1) {
my $char = $self->_peek;
last if !defined $char or $char !~ /\s/;
$self->_advance;
if ( $char eq "\n" ) {
$self->{line} += 1;
$self->{pos} = 0;
}
}
}
sub _eof($self) {
return !( scalar @{ $self->{input} } );
}
sub _peek($self) {
return $self->{input}[0];
}
sub _advance($self) {
return if $self->_eof;
$self->{pos} += 1;
return shift @{ $self->{input} };
}
sub _unexpected_input ( $self, $char ) {
die sprintf( "unexpected input '%s' in line %d at position %d\n",
$char, $self->{line}, $self->{pos} );
}
1;
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