NAME

Music::ToRoman - Convert notes and chords to Roman numeral notation

VERSION

version 0.1100

SYNOPSIS

use Music::ToRoman;

my $mtr = Music::ToRoman->new(
  scale_note => 'A',
  scale_name => 'minor',
);

my $roman = $mtr->parse('Am');  # i (minor)
$roman = $mtr->parse('Bo');     # iio (diminished)
$roman = $mtr->parse('Bdim');   # iio (diminished)
$roman = $mtr->parse('Bb');     # bII (flat-two major)
$roman = $mtr->parse('CM');     # III (major)
$roman = $mtr->parse('C');      # III (major)
$roman = $mtr->parse('Cm9/G');  # iii9/VII (minor ninth with seven bass)
$roman = $mtr->parse('Cm9/Bb'); # iii9/bii (minor ninth with flat-two bass)
$roman = $mtr->parse('D sus4'); # IV sus4 (major suspended)
$roman = $mtr->parse('DMaj7');  # IV maj7 (major seventh)
$roman = $mtr->parse('E7');     # V7 (dominant seventh)
$roman = $mtr->parse('Em7');    # v7 (minor seventh)
$roman = $mtr->parse('Fmin7');  # vi min7 (minor seventh)
$roman = $mtr->parse('G+');     # VII+ (augmented)

$mtr = Music::ToRoman->new(
  scale_note => 'A',
  scale_name => 'dorian',
  chords     => 0,
);

$roman = $mtr->parse('A');      # i
$roman = $mtr->parse('B');      # ii
$roman = $mtr->parse('C');      # III
$roman = $mtr->parse('D');      # IV
$roman = $mtr->parse('E');      # v
$roman = $mtr->parse('F#');     # vi
$roman = $mtr->parse('G');      # VII
$roman = $mtr->parse('Amin7');  # i min7
$roman = $mtr->parse('Bo');     # iio
$roman = $mtr->parse('CMaj7');  # III maj7
$roman = $mtr->parse('D7');     # IV7
$roman = $mtr->parse('Em');     # v

DESCRIPTION

Music::ToRoman converts named chords to Roman numeral notation. Also individual "chordless" notes may be converted given a diatonic mode scale_name.

ATTRIBUTES

scale_note

Note on which the scale is based. Default: C

This must be an uppercase letter from A-G either alone or followed by # or b.

scale_name

Name of the scale. Default: major

The diatonic mode names supported are:

ionian / major
dorian
phrygian
lydian
mixolydian
aeolian / minor
locrian

major_tonic

Note on which the major scale is based. Default: 'C'

This must be an uppercase letter from A-G and followed by a #.

This attribute is required when the scale_note is either a double-sharp or double-flat and the scale_name is neither major nor ionian.

chords

Are we given chords to parse with major (M) and minor (m) designations?

Default: 1

* Must be a Boolean value.

If this is set to 0, single notes can be used to return the major/minor Roman numeral for the given diatonic mode scale_name.

verbose

Show the progress of the parse method. Default 0

METHODS

new

$mtr = Music::ToRoman->new(
  scale_note => $note,
  scale_name => $name,
);

Create a new Music::ToRoman object.

parse

$roman = $mtr->parse($chord);

Parse a note or chord name into a Roman numeral representation.

For instance, the Roman numeral representation for the aeolian (or minor) mode is: i ii III iv v VI VII - where the case indicates the major/minor status of the given chord.

This can be overridden by parsing say, BM7 (B dominant seventh), thus producing II7.

If a major/minor chord designation is not provided, M major is assumed.

If the chords attribute is set to 0 and a single note is given, the diatonic mode of the scale_name is used to find the correct Roman numeral representation.

A diminished chord may be given as either o or dim, and both are rendered as o.

SEE ALSO

List::MoreUtils

Moo

Music::Scales

https://en.wikipedia.org/wiki/Roman_numeral_analysis

For example usage, check out the files eg/roman and eg/basslines in Music::BachChoralHarmony.

App::MusicTools vov is the reverse of this module, and is significantly powerful.

AUTHOR

Gene Boggs <gene@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2019 by Gene Boggs.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

cpanm Music::ToRoman

perl -MCPAN -e shell
install Music::ToRoman