Re: [abcusers] Re: Initial repeats
Someone incorrectly writes: : James is adamant that abc2midi won't play a repeat unless there's : a balanced begin/end. Damn! Take a day off work and someone decides to put nonsense words in your mouth! Just for the record, abc2midi does have code in there to guess the start of repeats when the start of repeat is missing. My point is that missing out a start repeat is bad notation; an anacrusis at the start of a piece generates ambiguity and I think you will be hard pressed to find a music textbook that legitimizes the process of missing off start repeats. James Allwright To subscribe/unsubscribe, point your browser to: http://www.tullochgorm.com/lists.html
Re: [abcusers] Re: Initial repeats
I beg to differ. (Incidentally Scarce Of Tatties is a jig that I rather like - it's in Sue Songer's Portland Collection). Version 1 - stripped to the bone X:1 K:A Mix Aee efg|edB A3:| aea a2e |edB A3:| is incorrect ABC but can be fixed up by guessing (YES, GUESSING!!) where the two repeats are supposed to go. The start of tune one works in this case - but I've seen too many where there are a few lead-in notes at the start of the tune that are not repeated. On these, the guess goes wrong. Some redundancy can be a good thing. Version 2 X:2 K:A Mix Aee efg|edB A3:: aea a2e |edB A3:| is still incorrect, but now there's only one error, i.e. one missing repeat-start. Arguing that O'Neil did it is flawed because as far as I know he never wrote any ABC. Arguing that there is so much ABC out there that does it that it has to be treated as de facto legal, alas, carries the day. This is what it says in the Muse source code: // Algorithm: // Keep count of the number of excess start-repeats. // If we arrive at the end with an excess, close them all // (We could consider doing so as soon as we see a start-repeat // as nested repeats are rare) // We keep track of the last good point to add a repeat and if ever // the count goes negative insert one there. Good points are the beginning // just before the first note or rest and after any repeat-end or double bar, // again just before the first note or rest. Version 3 X:3 K:A Mix |:Aee efg|edB A3:| |:aea a2e |edB A3:| Is correct. It does NOT have an empty bar because :| is not a bar line and nor is |:. The proof of this is that they can occur in the middles of bars. They are something pretty close to double-bars, which can also occur in the middles of bars (I believe the posh word is anacrusis). There seems to be a convention in tadpole land that where a double-bar coincides with a bar line you omit the bar line - that is you draw just two, not three - and I remember wrestling with some interesting ambiguities in the area of bar-length counting and stress-patterns when I wrote that part of Muse. Alas, I cannot now remember what they are. (I think there was (and may still be) a restriction in Barfly that repeats are only allowed at bar boundaries - but I also recall Phil admitting that is a restriction in Barfly caused by a misunderstanding when he wrote it. Laurie - Original Message - From: Jack Campin [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, December 16, 2001 1:58 AM Subject: Re: [abcusers] Re: Initial repeats A somewhat trickier problem is that there's currently a fair amount of abc tunes that don't even use the initial repeat on second and later sections. Some users seems to think that :| is a fine way to start a repeated section. This is also what many printed sources do, e.g. Kerr's Merry Melodies (as popular as all other Scottish tunebooks put together and then some) and the Northumbrian Pipers' Tunebooks (later numbers of which were typeset with abc2mtex, but I haven't seen those). It eliminates a bit of pointless visual clutter, which is why I use it. Humans and computers are equally able to work out where the repeat starts without an explicit mark. There is a problem with repeats in the middle of tunes that has never been discussed here as far as I can remember, and is mostly ignored by the 1.6 standard as it only discusses the staff notation generated by repeat signs, not their interpretation as music or the semantic constraints on them. Consider this typical piece of coding: X:1 T:Scarce of Tatties M:6/8 L:1/8 K:A Mix Aee efg|edB dBG|Aee efg|edB A3 | aaa gag|fgf eAA|Aee efg|edB A3:| aea a2e |g2f eAA|aea a2e |gaf e3 | eee AAA|d2f fee|Aee efg|edB A3:| Now this: X:2 T:Scarce of Tatties M:6/8 L:1/8 K:A Mix Aee efg|edB dBG|Aee efg|edB A3 | aaa gag|fgf eAA|Aee efg|edB A3:: aea a2e |g2f eAA|aea a2e |gaf e3 | eee AAA|d2f fee|Aee efg|edB A3:| And this: X:3 T:Scarce of Tatties M:6/8 L:1/8 K:A Mix |:Aee efg|edB dBG|Aee efg|edB A3 | aaa gag|fgf eAA|Aee efg|edB A3:| |:aea a2e |g2f eAA|aea a2e |gaf e3 | eee AAA|d2f fee|Aee efg|edB A3:| Version 1 is the Kerr's/NPTB style I use. In BarFly, version 2 produces a butt-ugly two-sided repeat sign at the end of the second line with the dots floating out in space at the margin; the result is that I never use double-sided repeats unless I know for sure that they're going to be displayed in the middle of a staff line. I like the edge of the staff to form an absolutely definite margin with no bits of notation hanging outside it. Version 3 *should* produce an error warning, as there is an empty bar between lines 3 and 4; this is no different from writing the first two lines as Aee efg|edB dBG|Aee efg|edB A3 | |aaa gag|fgf eAA|Aee efg|edB A3:| which BarFly correctly flags as an attempt to write a bar shorter than the time signature says. (In fact BarFly doesn't see the problem in 3, though according to the 1.6 standard, it
Re: [abcusers] Re: Initial repeats
On Mon, 17 Dec 2001, James Allwright wrote: My point is that missing out a start repeat is bad notation; an anacrusis at the start of a piece generates ambiguity and I think you will be hard pressed to find a music textbook that legitimizes the process of missing off start repeats. From The Norton Manual of Music Notation, First Edition (Heussenstamm, 1987): If a passage is to be repeated from the beginning of a piece, only one repeat sign is needed. John To subscribe/unsubscribe, point your browser to: http://www.tullochgorm.com/lists.html
[abcusers] Initial bar lines
John wrote: | On Mon, 17 Dec 2001, James Allwright wrote: | | My point is that missing out a start repeat is bad notation; an | anacrusis at the start of a piece generates ambiguity and I think you | will be hard pressed to find a music textbook that legitimizes the | process of missing off start repeats. | | From The Norton Manual of Music Notation, First Edition (Heussenstamm, | 1987): | | If a passage is to be repeated from the beginning of a piece, only one | repeat sign is needed. Yup; and there ain't a whole lot you're gonna do to fight this, unless you can somehow get control of all ABC software and add code to make it illegal. But on to a related, but new subject: A more seious problem is the common practice of omitting initial bar lines even when it's not the start of a repeat. This is another case where we can't fight it, but we could put subtle (or unsubtle) social pressure to change. I've run across this in the attempt to write code that does matching on the first few bars of a tune. The source of the problem is the question of whether the notes before the first bar line are a pickup or part of the tune. This is important, because pickups are notoriously variable. You want to exclude them from the match, because they will rarely match. What you want is to ignore them completely. But how does a piece of code recognize a pickup? The obvious answer is that a pickup is all the notes before the first bar line. But this doesn't work, because people often omit the first bar line when there's no pickup. You end up treating the first full bar as a pickup, which isn't what you want. So obviously, you count those notes, and if they're a full bar, you treat them as such? Not quite. It doesn't take much digging to learn that people are especially sloppy about their first bars, and the note lengths often don't add up right. You end up rejecting a lot of what should have been full bars because of this. Sometimes it's not even sloppiness; sometimes the first bar starts with a rest. Hardly anyone ever writes such rests, and the resulting first bar really does look like a pickup. This is a problem for live musicians, too, in some styles. At least it is to musicians who feel the difference between pickup notes and real melody notes. (And they'll likely get you in deeper, by pointing out that in some cases, the pickup is an important part of the tune which shouldn't be ignored. ;-) Another heuristic would be to say that an apparent pickup before the first bar is treated as melody if it's more than 1/2 of a measure. In the past couple weeks, I've transcribed several counterexamples to this. One was a tango, in 4/4 time, with 5/8 of a measure as pickup. This is not at all unusual in tangos. Another example was a tarantella, in 6/8 time, with 4/6 of a measure as a pickup. Tarantellas often have long pickups, sometimes 5/6 of the measure. So in both of these styles, even if the initial bunch of notes is only one tiny note short of a full measure, it might still be a pickup. Or it might be the first measure, which starts with a rest that was omitted. Or it could be incorrect note lengths due to the usual sloppy typing. So the obvious heuristics all have glaring counterexamples. What I've done so far is shrug and stick with my initial rule: Anything before the first bar line is a pickup, and is ignored. If someone doesn't write that first bar line, well, my code won't match their tune. The ideal solution would be for abc users to adopt the same policy. I can pretty much guess what are the chances of that ever happening. As I've noted before, we have a population of users who can't even be bothered to type X:1 at the start of their tunes. And lots of printed music omits all initial bar lines, even for first measures. The publishers don't care whether this causes problems. Oh, well; pattern matches don't have to be perfect to be useful. To subscribe/unsubscribe, point your browser to: http://www.tullochgorm.com/lists.html
Re: [abcusers] Initial bar lines
John Chambers said - As I've noted before, we have a population of users who can't even be bothered to type "X:1" at the start of their tunes. I've heard it said that if a door is clearly marked PULL but everyone who comes to it tries to PUSH, it is not because they are all stupid; it is because the door opens the wrong way. Bryan Creer
Re: [abcusers] Re: Initial repeats
Ah. I do apologise for maligning your software! L. - Original Message - From: Phil Taylor [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Monday, December 17, 2001 7:27 PM Subject: Re: [abcusers] Re: Initial repeats Laurie Griffiths wrote: (I think there was (and may still be) a restriction in Barfly that repeats are only allowed at bar boundaries - but I also recall Phil admitting that is a restriction in Barfly caused by a misunderstanding when he wrote it. No, repeats can go anywhere, and don't have to coincide with metric bars. The limitation you are probably thinking of is that BarFly won't produce a line break in the music unless there's a bar line (any kind) at the end of the line. Phil Taylor To subscribe/unsubscribe, point your browser to: http://www.tullochgorm.com/lists.html To subscribe/unsubscribe, point your browser to: http://www.tullochgorm.com/lists.html
Re: [abcusers] Initial repeats
repeat signs are bars, I don't think so. At a quick glance, seven out of the first twelve tunes in the Northumbrian Piper's Tune Book have repeat symbols that don't coincide with bars. Okay, I guess both I and the 1.6 standard are wrong on that. For instance, I want to be able to do this - X:1 T:Brighton Camp I:abc2nwc M:4/4 L:1/8 K:G |:gf|e2dc B2A2|B2G2E2D2|G2G2GABc|d4B2gf| e2dc B2A2|B2G2E2G2|FG A2D2EF|G4G2:| |:dc|B2d2e2f2|g2dc BA G2|Bc d2e2f2|g4f2gf| e2dc B2A2|B2G2E2G2|FG A2D2EF|G4G2:| Leaving out the first |: would be no problem but I prefer to keep the second. Insisting that repeat symbols coincide with barlines produces something like - gf|:e2dc B2A2|B2G2E2D2|G2G2GABc|d4B2gf| e2dc B2A2|B2G2E2G2|FG A2D2EF|1G4G2gf:|2G4G2dc|] B2d2e2f2|g2dc BA G2|Bc d2e2f2|g4f2gf| e2dc B2A2|B2G2E2G2|FG A2D2EF|1G4G2dc:|2G4G2|] which is unnecessarily complicated and ambiguous about where the repeat of the second half starts. You're right about the unnecessary complication, but the convention in sources like Kerr's is absolutely clear. If ABC had a nested-repeat construction there would be an ambiguity, but that's years away. I just looked that tune up in O'Neill's 1001 (it's #972). There is a notational convention there that I really *don't* think we oughta emulate... read a dotted crotchet as a minim??? For this one, he did put a repeat at the start of the line (he does it different ways in different places in the same book). Kerr (v3, The Girl I Left Behind Me) puts the whole tune on one line with no initial repeat and a double-sided repeat in the middle, his usual practice for tunes short enough to fit. Does anybody's software support O'Neill's attitude to clefs and key signatures? - one per tune is enough. I think I've seen that in other Irish sources. I don't mind either way. I think I've seen other Irish stuff that dropped the clef at the start too: you assume treble, trusting that St Patrick drove the others out of Ireland. You can do wonders of compression with nested repeats. There is a sheet in Murdoch Henderson's manuscripts titled 64 Great Scottish Reels in A Major, and he gets them all on one side, one line each, 64 lines (the sheet is the size of a folded tabloid page). There's no hint in the manuscripts of why he wanted to do this in the first place. Must have taken him days. === http://www.purr.demon.co.uk/jack/ === To subscribe/unsubscribe, point your browser to: http://www.tullochgorm.com/lists.html
