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Writer-friendly Gregorian notation format compiling to gabc.

One or more scores per file; generate pdf preview without need to write a single line of LaTeX code; write music and lyrics separately.

GLY is an acronym of "Gregorio for liLYponders" or "Gregorio with separate LYrics.


One of the most popular solutions for typesetting square notation used for the Gregorian chant is Gregorio.

Gregorio is a great tool, but I really don't like it's default input format gabc - it's not very well readable, pain to write, and too restrictive (for some reason doesn't support other than the predefined header fields). That led me to designing an alternative, Gregorio-inspired notation format, which compiles to pure Gregorio gabc.

(Existence of the GABC Transcription Tool by Benjamin Bloomfield suggests that the author of gly wasn't the only one who prefered to enter music and lyrics separately.)


gly language

  • music separated from lyrics
    • no need of the ubiquitous and tedious parentheses
    • music transcription is usually quicker and more comfortable
    • separation of "material and form" -> easy copying of the music or lyrics alone is possible (useful for a composer)
    • syllabified lyrics entered in a format inspired by LilyPond
  • music and lyrics can be interspersed as needed
  • no semicolons in the header
  • custom header fields
  • several scores per file

gly tool

  • transform your gly document to one or more gabc scores
  • compile pdf preview with a single command, without writing any (La)TeX
    • produces score annotations from provided score header fields
  • transform gly document to (modern notation) lilypond document

Real world examples

Basic examples

Typical GABC source of an antiphon looks like this:

name: Nativitas gloriosae;
office-part: laudes, 1. ant.;
occasion: In Nativitate B. Mariae Virginis;
book: Antiphonale Romanum 1912, pg. 704;
mode: 8;
initial-style: 1;

(c4) NA(g)TI(g)VI(g)TAS(gd) glo(f)ri(gh)ó(g)sae(g) * (,)
Vír(g)gi(g)nis(hi) Ma(gh)rí(gf)ae,(f) (;)
ex(f) sé(g)mi(h)ne(h) A(hiwji)bra(hg)hae,(g) (;)
or(gh~)tae(g) de(g) tri(g)bu(fe/fgf) Ju(d)da,(d) (;)
cla(df!gh)ra(g) ex(f) stir(hg~)pe(hi) Da(h)vid.(g) (::)

Corresponding GLY may look like this:

name: Nativitas gloriosae
office-part: laudes, 1. ant.
occasion: In Nativitate B. Mariae Virginis
book: Antiphonale Romanum 1912, pg. 704
mode: 8
initial-style: 1

c4 g g g gd f gh g g ,
g g hi gh gf f ;
f g h h hiwji hg g ;
gh~ g g g fe/fgf d d ;
df!gh g f hg~ hi h g ::

NA -- TI -- VI -- TAS glo -- ri -- ósae *
Vír -- gi -- nis Ma -- rí -- ae,
ex sé -- mi -- ne A -- bra -- hae,
or -- tae de tri -- bu Ju -- da,
cla -- ra ex stir -- pe Da -- vid.

Or, with music and lyrics interlaced (this arrangement may be handy for larger scores, like full-notated hymns, sequences or nocturnal responsories):

name: Nativitas gloriosae
office-part: laudes, 1. ant.
occasion: In Nativitate B. Mariae Virginis
book: Antiphonale Romanum 1912, pg. 704
mode: 8
initial-style: 1

c4 g g g gd f gh g g ,
NA -- TI -- VI -- TAS glo -- ri -- ósae *

g g hi gh gf f ;
Vír -- gi -- nis Ma -- rí -- ae,

f g h h hiwji hg g ;
ex sé -- mi -- ne A -- bra -- hae,

gh~ g g g fe/fgf d d ;
or -- tae de tri -- bu Ju -- da,

df!gh g f hg~ hi h g ::
cla -- ra ex stir -- pe Da -- vid.

Other arrangements are also possible. Order of music and lyrics is actually ignored during processing.

Syntax - Short Description

Score begins with a \score keyword. Header fields follow. The header syntax is very similar to gabc, except for semicolon at the end (omitted in gly) and the fact that only one-line values are supported. Unlike in gabc, there is no delimiter signaling end of the header. Header ends with first line detected as music or lyrics.

Music lines contain only music. There is usually no need to enclose music chunks in parentheses (the author's bias against writing so many parentheses was one of the main motivations behind creating gly), but you are allowed to write them if you want to.

Lyric lines contain lyrics, with syllables separated by double dash -- like in LilyPond.

For more detailed description of gly syntax see Syntax Reference below.


Install Ruby (some 2.x version) runtime. Then install as any ruby gem:

gem install gly

If you plan to use gly preview, ensure that you have a working installation of gregorio and lualatex.

If you also plan to use the gly->lilypond translation, install the lygre gem. (This feature is currently only for the brave. But better support is planned.)


This gem provides executable gly. Run gly help for full list of subcommands. The most important ones are:

gly gabc FILE1 ...

converts given gly file(s) to one or more gabc files (one per score, i.e. one gly may spawn a bunch of gabcs).

gly preview FILE1 ...

creates a pdf document with all scores contained in each gly file.


Emacs mode with syntax highlighting for gly

Editing gly in emacs

Syntax Reference

Gly syntax is line-based. The interpreter reads the input line by line, and depending on context it interprets each line as e.g. music, lyrics or header field.

The syntax is quite permissive, not requiring a lot of delimiters or hints for the parser concerning what each line means. Mostly the parser guesses the meaning correctly. Where not, meaning of each line can be stated explicitly.


When a % sign is encountered, everything until the end of line is considered a comment and not interpreted. (Comment syntax is the same as in gabc.)

Please note, that when compiling to gabc, comments are dropped and don't appear in the resulting gabc file.

2. Whitespace

Empty lines are ignored.

3. Scores

A new score begins at the beginning of a file or at a line containing a single keyword '\score'.

It consists of a header (optional, only permitted at the beginning of a score) and music- and lyrics-lines. Lines with music and lyrics may appear in any order.

Score ends with end of file or with explicit beginning of a new score or another top-level element.

3.1 Score header

Score header starts at the beginning of the score and ends with first non-empty line identified by the parser as music or lyrics. Like in gabc it is optional - you aren't required to include header in a score.

Header consists of fields. Each header field is on it's own (one) line and consists of identifier, colon and value:

name: Nativitas gloriosae
office-part: laudes, 1. ant.
occasion: In Nativitate B. Mariae Virginis
book: Antiphonale Romanum 1912, pg. 704
mode: 8
initial-style: 1

Header field identifier may only consist of alphanumeric characters, minus-sign and underscore. Value can contain anything.

Header field 'id' is special: if present, it is used as suffix of the generated gabc file (instead of the default, which is numeric position of the score in the source document).

3.2 Lyrics

Syntax of lyrics is inspired by LilyPond. Lyrics have to be manually syllabified. Default syllable delimiter is double dash (minus) -- with optional whitespace around.

cla -- ra ex stir -- pe Da -- vid.

Underscore can be used to enter a "joining" space, to set two or more words under a single note/neume. Some languages, like Czech or Italian, use this feature. The underscore will be replaced by a space in the gabc output.

Pán s_vá -- mi.

The parser guesses meaning of each line by attempting to find syllable separator in it and by looking if it's alphanumeric characters contain something that cannot be interpreted as music. If any of these conditions is met, the line is interpreted as lyrics.

If gly fails to guess your lyrics line correctly and interprets it as music, place \lyrics or it's shorter form \l at the beginning of the unhappy line:

\l a a a

For the opposite case there is \music and it's shortcut \m.

\m a[alt:když něco poplete autodetekci] j ivHG

\lyrics or \music alone on it's own line starts a lyrics/music block mode. It means that until the next block opening keyword is encountered (\lyrics, \music, \header, \score), default line meaning is lyrics/music. Again, this is handy mostly when gly fails to guess your intentions.

In case you prefer another syllable separator over the default double dash, there is a command line switch --separator or -s for this purpose. However, setting a custom syllable separator can have tricky consequences due to the way how gly guesses meaning of lines.

3.3 Music

Any line appearing in a score and not identified as header field or lyrics is music by default.

Music line contains one or more music chunks separated by whitespace. For music syntax see official gabc documentation - gly doesn't change anything in this respect.

Music chunks may be enclosed in parentheses as in gabc. That is especially useful in two cases:

  • empty music chunk ()
  • music chunk containing space (gf gf g!hi)

3.4 Matching lyrics to music

When processing the gly source and producing gabc, music chunks are matched to lyric syllables.

There are, however, a few special cases, to make it work conveniently:

These special cases of music chunks don't get lyric syllable:

  • clef
  • music chunk containing only a division bar (eventually accompanied by a line break z or Z)

Exception to this rule are 'nonlyrical lyrics chunks'. Currently there is only one built-in nonlyrical lyric chunk: asterisk *. Normally it is treated as any other syllable, but if it meets a division, it is set as it's lyrics, while a normal syllable wouldn't be.

If you need to set some other syllable under a division, make it 'nonlyrical' by placing an exclamation mark at it's beginning, e.g. !<i>Ps.</i>

In the other direction it is sometimes necessary to set a syllable not matching any music at all. In such cases empty music chunk () is what you need.

Explicit empty lyrics syllable can be produced by a lone exclamation mark !. It is sometimes handy when gly doesn't recognize a non-singable music chunk.

3.5 Markup

Between scores (and only between scores) you can use one-line

\markup My annotation

and block

My annotation
when I plan it long

markup. gly preview will insert the content of your markups into the tex document it generates. Markup is inserted as is - just with the \markup keyword + leading and trailing whitespace stripped. It means you can use TeX commands and other constructs that make sense in a TeX document.

4. Document header

Each gly document may optinally contain a document header. It may appear anywhere in the document, but best practice is to place it at the very beginning.

Document header starts with keyword \header and ends at the end of file or at the beginning of another top-level element. The syntax of it's content is the same as for score header.

title: Hebdomada III Adventus

Field 'title' in the document header is, if present, used by gly preview as title of the generated pdf.


For quick transcription or composition the default output of gly preview is possibly good enough. But what if you want to customize the output? Switch font, fine-tune page geometry, use custom headings? No problem! gly understands your desire for beautiful music sheets.

The easiest way to customize the overall look-and-feel of your gly previews is a custom LaTeX template.

normally it would be a valid LaTeX document prepared for gregorio (i.e. compatible with lualatex, importing all the necessary packages) and containing two placeholders:

  • {{glyvars}} in the preamble - it will be replaced by several LaTeX command definitions making available for you contents of the document header fields
  • {{body}} in the document body - it is where scores will be inserted.

The double curly braces tell gly "this is a placeholder" - the placeholder format is borrowed from popular templating engines.

See the default template for inspiration.

Render a preview with your fancy new template by invoking

gly preview -t TEMPLATE.tex DOCUMENT.gly

How to run tests

execute tests/run.rb