Lessons · Usage guide

Keeping a document honest

rules, help, and reusing a name

% A file runs top to bottom against ONE kernel, so what is in scope at
% any line is whatever the lines above it put there. Two commands
% help with that scope: 'rules' shows it and 'help' documents it. Here is the first of two pieces, a minuet phrase:
 
bpm 66
instrument plain
meter 3
unit 1/4
key eb4 maj
 
Theme ::= 5 _2 3 _2 1 _2 2 3 4 3 _3 2 _2 4 _2 3 _2 2 1 .7 1 _3
Theme
 
 
% Answer is Theme a fifth up; Bass steps I V IV V under the pair, so the
% four bars hang on the dominant. Three rules are the whole minuet;
% nothing else is stated for it.
 
Answer ::= Theme@~4
Bass   ::= .1 _6 .5 _6 .4 _6 .5 _6
 
{Theme Answer, Bass*2}
 
 
% 'rules' prints the grammar in force AT THIS LINE: the three above,
% each body as the engine holds it, so Answer prints as '{ Theme }@~4',
% the reference it is. It sounds nothing, so the block states music of
% its own: answer leading, bass backwards to V IV V I, closing what
% block two left hanging.
 
rules
{Answer Theme, Bass~*2}
 
 
% A second piece in the same file states its own tempo, meter and key,
% and defining a name again replaces it from that line on, which is what
% lets it reuse the names Theme and Answer. This Theme climbs 5 6 7 '1
% across the augmented second of harmonic minor and falls back through
% it, over a tonic pedal:
 
bpm 99
meter 4
unit 1/4
key f#4 harm
 
Theme ::= 1 2 3 1 4 3 2 _2 5 6 7 '1 7 6 5 _2
Ped   ::= .1 _4
 
{Theme Theme@~2, Ped*8}
 
 
% This Answer line is character for character the one in the minuet;
% defined again, the name now means something else: Theme a fifth
% up in F sharp harmonic minor, in 4, over the pedal.
 
Answer ::= Theme@~4
 
{Theme Answer, Ped*8}
 
 
% 'help' prints the full reference into the tray (every mark, command,
% chord and drum name) and changes no state. Finale: the line, its
% answer, the answer a third down (which is the line a third up; the
% engine checks it), then the line backwards, closing on the tonic it
% has pedalled throughout.
 
help
assert Answer@~-2 == Theme@~2
 
{Theme Answer Answer@~-2 Theme~, Ped*16}

% A file runs top to bottom against ONE kernel, so what is in scope at
% any line is whatever the lines above it put there. Two commands
% help with that scope: 'rules' shows it and 'help' documents it. Here is the first of two pieces, a minuet phrase:

bpm 66
instrument plain
meter 3
unit 1/4
key eb4 maj

Theme ::= 5 _2 3 _2 1 _2 2 3 4 3 _3 2 _2 4 _2 3 _2 2 1 .7 1 _3
Theme

% Answer is Theme a fifth up; Bass steps I V IV V under the pair, so the
% four bars hang on the dominant. Three rules are the whole minuet;
% nothing else is stated for it.

Answer ::= Theme@~4
Bass   ::= .1 _6 .5 _6 .4 _6 .5 _6

{Theme Answer, Bass*2}

% 'rules' prints the grammar in force AT THIS LINE: the three above,
% each body as the engine holds it, so Answer prints as '{ Theme }@~4',
% the reference it is. It sounds nothing, so the block states music of
% its own: answer leading, bass backwards to V IV V I, closing what
% block two left hanging.

rules
{Answer Theme, Bass~*2}

% A second piece in the same file states its own tempo, meter and key,
% and defining a name again replaces it from that line on, which is what
% lets it reuse the names Theme and Answer. This Theme climbs 5 6 7 '1
% across the augmented second of harmonic minor and falls back through
% it, over a tonic pedal:

bpm 99
meter 4
unit 1/4
key f#4 harm

Theme ::= 1 2 3 1 4 3 2 _2 5 6 7 '1 7 6 5 _2
Ped   ::= .1 _4

{Theme Theme@~2, Ped*8}

% This Answer line is character for character the one in the minuet;
% defined again, the name now means something else: Theme a fifth
% up in F sharp harmonic minor, in 4, over the pedal.

Answer ::= Theme@~4

{Theme Answer, Ped*8}

% 'help' prints the full reference into the tray (every mark, command,
% chord and drum name) and changes no state. Finale: the line, its
% answer, the answer a third down (which is the line a third up; the
% engine checks it), then the line backwards, closing on the tonic it
% has pedalled throughout.

help
assert Answer@~-2 == Theme@~2

{Theme Answer Answer@~-2 Theme~, Ped*16}

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

Keeping a document honest · Usage guide