Lessons · Advanced

Stamping a figure

Stamping a figure through a line

% An accompaniment figure is a shape with no pitch of its own.
% Alberti climbs a fifth, drops a third and rocks back, all in scale
% steps, so an anchor plus Alberti is root, fifth, third, fifth, and
% one anchor per chord already spells i iv V i:
 
bpm 70
instrument plain
meter 4
unit 1/4
key f harm
 
Alberti ::= s4 s-2 s2
 
..1 Alberti ..4 Alberti ..5 Alberti ..1 Alberti
 
 
% ANCHOR APPLICATION says that in one line: 'Alberti(a b c)' states
% the rule once after every anchor in turn. The anchors carry the
% harmony, the rule is the hand playing it, and the assert proves the
% call and the longhand identical. Then i iv V i, then i VI iv V:
 
assert Alberti(..1 ..4) == { ..1 Alberti ..4 Alberti }
 
Alberti(..1 ..4 ..5 ..1)
Alberti(..1 ..6 ..4 ..5)
 
 
% Every step is measured from the note before it, not from the
% anchor, so a figure is written as the walk it makes. Arp is a third,
% a third, a fourth: the same triads rolled up to the octave instead
% of rocking inside a fifth. Same eight anchors, same chords:
 
Arp ::= s2 s2 s3
 
Arp(..1 ..4 ..5 ..1)
Arp(..1 ..6 ..4 ..5)
 
 
% Application is EXPRESSION-level only. Inside a rule body the
% parentheses are EBNF grouping and '=' separates alternatives, so
% Hand is a CHOICE of figure rather than a call, four derivations,
% and the fourth takes the roll for both chords:
 
Hand ::= ..1 (Alberti = Arp) ..5 (Alberti = Arp)
 
Hand#1 Hand#4
 
 
% A stamped run is an expression like any other, so it carries a
% melody above it. The first field sets the length (sixteen units of
% stamped bass), and each tune is written to fill exactly that:
 
Tune  ::= 1 _2 3 _2 4 _4 3 _2 2 _2 1 _4
TuneB ::= 3 _2 2 _2 1 _4 4 _4 2 _4
 
{Alberti(..1 ..4 ..5 ..1), Tune}
{Arp(..1 ..6 ..4 ..5), TuneB}
 
 
% The phrase whole, one idea dressing all of it: i iv V i rolled, the
% turn to i VI iv V rocking, the roll again, and a last i iv V i under
% a close that walks 3 2 1 down, leans on .7 as the V arrives, and
% resolves up to the tonic.
 
Close ::= 3 _2 2 _2 1 _4 .7 _4 1 _4
 
{Arp(..1 ..4 ..5 ..1), Tune}
{Alberti(..1 ..6 ..4 ..5), TuneB}
{Arp(..1 ..4 ..5 ..1), Tune}
{Alberti(..1 ..4 ..5 ..1), Close}

% An accompaniment figure is a shape with no pitch of its own.
% Alberti climbs a fifth, drops a third and rocks back, all in scale
% steps, so an anchor plus Alberti is root, fifth, third, fifth, and
% one anchor per chord already spells i iv V i:

bpm 70
instrument plain
meter 4
unit 1/4
key f harm

Alberti ::= s4 s-2 s2

..1 Alberti ..4 Alberti ..5 Alberti ..1 Alberti

% ANCHOR APPLICATION says that in one line: 'Alberti(a b c)' states
% the rule once after every anchor in turn. The anchors carry the
% harmony, the rule is the hand playing it, and the assert proves the
% call and the longhand identical. Then i iv V i, then i VI iv V:

assert Alberti(..1 ..4) == { ..1 Alberti ..4 Alberti }

Alberti(..1 ..4 ..5 ..1)
Alberti(..1 ..6 ..4 ..5)

% Every step is measured from the note before it, not from the
% anchor, so a figure is written as the walk it makes. Arp is a third,
% a third, a fourth: the same triads rolled up to the octave instead
% of rocking inside a fifth. Same eight anchors, same chords:

Arp ::= s2 s2 s3

Arp(..1 ..4 ..5 ..1)
Arp(..1 ..6 ..4 ..5)

% Application is EXPRESSION-level only. Inside a rule body the
% parentheses are EBNF grouping and '=' separates alternatives, so
% Hand is a CHOICE of figure rather than a call, four derivations,
% and the fourth takes the roll for both chords:

Hand ::= ..1 (Alberti = Arp) ..5 (Alberti = Arp)

Hand#1 Hand#4

% A stamped run is an expression like any other, so it carries a
% melody above it. The first field sets the length (sixteen units of
% stamped bass), and each tune is written to fill exactly that:

Tune  ::= 1 _2 3 _2 4 _4 3 _2 2 _2 1 _4
TuneB ::= 3 _2 2 _2 1 _4 4 _4 2 _4

{Alberti(..1 ..4 ..5 ..1), Tune}
{Arp(..1 ..6 ..4 ..5), TuneB}

% The phrase whole, one idea dressing all of it: i iv V i rolled, the
% turn to i VI iv V rocking, the roll again, and a last i iv V i under
% a close that walks 3 2 1 down, leans on .7 as the V arrives, and
% resolves up to the tonic.

Close ::= 3 _2 2 _2 1 _4 .7 _4 1 _4

{Arp(..1 ..4 ..5 ..1), Tune}
{Alberti(..1 ..6 ..4 ..5), TuneB}
{Arp(..1 ..4 ..5 ..1), Tune}
{Alberti(..1 ..4 ..5 ..1), Close}

running…edit it and it re-runs as you type

Stamping a figure · Advanced