The strophe command permits the user to extract selected information paths (called strophes) present in a Humdrum input.

Structurally, strophic data must begin from a single common spine, split apart into two or more alternative spines, and then rejoin to form a single spine. Since the strophes split from a common spine, all strophic data necessarily begin by sharing the same data type. Different exclusive interpretations may be introduced in the strophic passage -- provided all strophic spines end up sharing the same data type just prior to being rejoined.

The beginning of a strophic passage is signalled by the presence of a strophic passage initiator -- a single asterisk followed by the keyword "strophe" (*strophe). The end of a strophic passage is signalled by the strophic passage terminator -- a single asterisk followed by the upper-case letter `S' followed by a minus sign (*S-). Each spine within the strophic passage begins with a strophe label and ends with a strophe end indicator (*S/fin).

Strophe labels may consist of either alphanumeric names, or numbers. Numerical labels should be used when the strophic data imply some sort of order, such as verses in a song. Alphanumeric labels are convenient for distinguishing different editions or ossia passages. The following example encodes a melodic phrase containing four numbered verses from "Das Wandern" from Die Schöne Müllerin by Schubert.

!! Franz Schubert, `Das Wandern' from "Die Schoene Muellerin"

**kern	**text
*>[V,V,V,V]	*>[V,V,V,V]
*>V	*>V
*k[b-e-]	*Deutsch
*	*solo
*	*strophe
*	*^
*	*^	*^
*	*S/1	*S/2	*S/3	*S/4
8f	Das	Vom	Das	Die
=5	=5	=5	=5	=5
8f	Wan-	Was-	sehn	Stei-
8b-	-dern	-ser	wir	-ne
8a	ist	ha-	auch	selbst ,
8ee-	des	-ben	den	so
=6	=6	=6	=6	=6
(16dd	Mül-	wir's	Rä-	schwer
)16ff	|	|	|	|
(16dd	-lers	ge-	-dern	sie
)16b-	|	|	|	|
8f	Lust ,	-lernt ,	ab ,	sind ,
8dd	das	vom	den	die
=7	=7	=7	=7	=7
(8.cc	Wan-	Was-	Rä-	Stei-
)16a	|	|	|	|
8b-	-dern !	-ser !	-dern !	-ne !
8r	%	%	%	%
*	*S/fin	*S/fin	*S/fin	*S/fin
*	*v	*v	*v	*v
*	*S-
*-	*-

The strophic passage in the above example pertains only to the spine marked **text. Following the strophic passage indicator (*strophe), the spine is split apart until the required number of verses are generated. Then each spine is labelled with its own strophe label. Since the verses have an order, it is appropriate to label them with numbers:*S/1, *S/2, and so on. The individual verses are terminated with strophe end indicators (*S/fin), the spines rejoin, and then a strophic passage terminator (*S-) marks the end of the strophic passage.

Executing the command:

strophe -s 4

produces the following output:

!! Franz Schubert, `Das Wandern' from "Die Schoene Muellerin"

**kern	**text
*>[V,V,V,V]	*>[V,V,V,V]
*>V	*>V
*k[b-e-]	*Deutsch
*	*solo
8f	Die
=5	=5
8f	Stei-
8b-	-ne
8a	selbst ,
8ee-	so
=6	=6
(16dd	schwer
)16ff	|
(16dd	sie
)16b-	|
8f	sind ,
8dd	die
=7	=7
(8.cc	Stei-
)16a	|
8b-	-ne !
8r	%
*-	*-

When extracting a single strophe, either the abbreviated or through-composed versions can be used as input. However, when using the strophe command to select more than one strophe for output, it is essential that the input first be expanded to a through-composed version, via the thru command. For example, in order to select the first and third verses in the above passage by Schubert, the user would need to execute the following command pipeline:

thru wandern | strophe -s 1,3

The list following the -s option can contain individual strophes separated by commas. For example, the following command extracts verses 1, 3 and 4 in succession:

thru wandern | strophe -s 1,3,4

Strophes may also be output in non-numeric order as in the following command invocation:

thru wandern | strophe -s 4,3,2,1

If the -x option is invoked, strophe outputs only a single strophe whose string label is specified as an option. Strophe names need not be numerical. E.g.

strophe -x ossia

If the strophe command is invoked without any option, then all strophes are expanded in the output in numerical order beginning with strophe 1. Missing numerical strophes (such as a missing strophe S/3 in a four-strophe encoding) will cause an error to be generated and terminate the strophe command.

Note that the strophe command allows strophe numbers containing a single decimal point, such as strophe *S/4.2. Having extracted the verse *S/1, the strophe command will output verse *S/1.1 in preference to *S/2 -- if the decimal strophe is present. This feature allows more than one strophic passage to be encoded within a single abbreviated format file. This feature might prove useful, for example, in a musical work that contains a brief refrain in the middle of each verse.

The various strophe-related tandem interpretations are summarized below:

*strophe	strophic passage initiator
*S-	strophic passage terminator
*S/string	strophe name label
*S/n[.n]	strophe number label
*S/fin	strophe end indicator

Note that for each strophic passage, all strophe labels must appear on the same record. See EXAMPLES below.

-h	displays a help screen summarizing the command syntax
-s strophe_list	output numbered strophes according to strophe_list
-x strophe_label	output only strophes labelled strophe_label

strophe file

will produce the following output:

!! `strophe' example.
**example	**bar
*thru	*thru
*>A	*>A
A	i
*>V	*>V
*	**foo
*	*thru
B	1
*	**bar
*	*thru
C	refrain
B	1
*>V	*>V
*	**foo
*	*thru
B	2
*	**bar
*	*thru
C	refrain
B	2
*>Coda	*>Coda
*	**foo
*	*thru
E	i
*-	*-

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