Starting with John Playford in the late 1600s, there were lot of publications in northwestern Europe of music for the kinds of dancing often called "country dance" in English. These sometimes contained dance descriptions, typically with a single tune for each dance. An extensive vocabulary developed for describing these dances, and new printing technology produced much cheaper publications over time, making the music and dance more widely available.
The purpose of this document is to describe some of the problems with transcribing this music and the dance instructions, into the popular ABC notation, and the (semi-)solutions that the transcribers have worked out.
Most of the time, it's most practical to transcribe each tune/dance as a separate file. These can be combined into larger files by various software, depending on how you are using them.
The simplest file names are just the title, with '_' used as a separator, and ".abc" as a suffix. Initial articles are usually dropped. This results in the "alltunes.abc" files being in alphabetical order by title. If a title exists in more than one source text, and the music or dance description have significant differences, there may be multiple transcriptions, with a number or other code name for the volume added to the end of the title. Nearly-identical versions from several sources may be put in a single file, with several S: lines listing the sources. All this may change with time, in an attempt to make sense of all the different versions of published dance tunes.
In some cases, we want to preserve the order of the tunes in a volume, or in several volumes. This is usually done with a file name that starts with a string of digits, plus '_' and then the title as above. Some formats used are VPNN_Title.abc, VPPPN_Title.abc, VVNNN_Title.abc, etc. In these, V is the volume/book number, P is the page number, and N is the number (on the page, or sequentially starting with the book's first tune). Not all books have page numbers, and some books have at most one tune per page, and the total count of pages or tunes may require 2 or 3 digits. The width of such numbers in the file names should be documented for each collection.
There are many problems with the dance descriptions. The text is often not of good quality. Walsh and Wright were known for using the cheapest printing of the time. This made their music widely available, but didn't result in high-quality historical documents. Punctuation is often lost, periods and commas are difficult to distinguish, and random specks can look like periods. The thin parts of letters often fade or disappear. In the worst cases, "??" is used to indicate an illegible portion of text. In general, most of the words are legible (or can be inferred from context), but the punctuation shouldn't be considered reliable.
In many cases, there are explicit statements or good clues in the dance to determine the tune's repeat pattern. When this isn't clear, I've generally transcribed the repeat symbols as-is, which is usually different from modern practice. Initial double bars or begin-repeat symbols are used for full first bars, as is common with some publishers (but not others). Musicians playing for dancing may have to figure out the appropriate repeat pattern. It was common in the 18th century to omit final repeat symbols, and in such cases, the final repeat sign is added to match current practice. In some cases, the dance description describes the repeats, and the tune is modified (if necessary) to match that. And of course, when you're not playing a tune for its dance, you can use any repeat pattern you like.
Initial articles ("the", "a", "an" and similar words in other languages) are omitted in file names, and are lower case in the T: header. This is sometimes recommended for computer files, since it makes correct alphabetization easy in different languages by using the rule "Sort on the titles without their initial lower-case letters." Writing code to detect the language and spot articles is extremely difficult, so the task is best left to human transcribers.
Many of the publications of this era follow the early practice of only using sharps and flats, but not natural signs. So an accidental in the key signature is cancelled with a sharp or flat, not a natural. ABC follows the modern practice of using naturals in such cases. Some publications use this scheme, and also contains natural signs in some tunes. Sometimes you see both in a single tune. It's messy.
The dance descriptions use some abbreviations and non-typable "icons", mostly as dance phrase boundaries. The icons have been typed in the ABC with typable "tokens" similar to the icons, but usually rotated by 90°. These icons seem to be used in no consistent fashion, so all they really indicate is the end of a "strain", the common term at the time for the major sections of a tune and/or dance. Here are the commmon abbreviations: