barlines -- "common system" for representing barlines

DESCRIPTION

Several Humdrum representations employ a common system for representing barlines. This common system is described below. (N.B. This common system is not intended to preclude other ways of representing barlines in Humdrum.)

In the common system, barlines are represented as logical entities, with optional signifiers for specifying the precise visual appearance of the barlines. Barlines are logically signified by the presence of an equals-sign (=) in the first column of a spine. Immediately after the equals sign there may follow an optional integer value indicating the measure number (e.g. =107 -- for measure 107). In addition, a lower-case alphabetic character may be appended to the measure number -- as in: =14b. This convention permits the user to distinguish measure numbers for first and second endings, etc. Measure numbers refer to the measure immediately following the barline, thus the token =23 occurs just prior to the encoded data for measure 23.

Double barlines are indicated by a minimum of two successive equals signs (==). Several consecutive equals signs may be encoded in order to enhance readability (e.g. =======).

An additional attribute for barlines is the pause -- which is represented by the-- icolon (;). Thus the token =4; means that the barline starting measure number 4 has a pause written above or below it, while the token =====; means that a double barline contains a pause indication.

Barlines can be visually rendered in a variety of ways. Where appropriate, users can specify more precisely the notational appearance of the barline by appending additional signifiers to the basic signifiers identified above. Barlines may be normal or heavy in width. Barlines of normal width are represented by the addition of the vertical bar (|). Heavy barlines are signified by the exclamation mark (!). Dotted barlines are signified by the double quote character ("). Partial barlines (extending between the second and fourth lines) are signified by the single quote character ('). Partial barlines (rendered as a short vertical stroke across the top of the staff) are signified by the single greve character (`). "Invisible" barlines are signified by the minus sign (-). In addition, barlines may be associated with repetition marks -- pointing left, right, or in both directions. The repeat sign is denoted by the colon character :). (Note that this repeat sign is a visual signifier, rather than a logical signifier of repetition; see section labels (3) and thru (4) for information concerning repetition.) All of these visual signifiers may be combined to form complex visual representations, such as a triple barline consisting of a normal line, followed by a heavy line, followed by a normal line, followed by a repeat indicator. See EXAMPLES below.

SIGNIFIERS

The following table summarizes the mappings of signifiers and signifieds for "common system" barlines.

0-9	measure numbers
a-z	alternate measures
;	pause
=	barline
==	double barline
|	normal width visual rendering
!	heavy width visual rendering
'	partial barline (from second to fourth line)
`	partial barline (short stroke at top of staff)
-	invisible barline
:	repeat sign

Summary of **kern-like Barline Signifiers

humsed, num

• Pertinent description
• Index to Humdrum Representations
• Index to Humdrum Commands
• Table for Contents for Humdrum User Guide