Velato is an esoteric programming language by User:Rottytooth, which uses MIDI files as source code. Programs in Velato, like in Fugue, are defined by the pitch and order of notes. Velato is intended to allow for flexibility in composition, so functional programs will not necessarily sound like random notes. There is a tendency for Velato programs to have jazz-like harmonies.
All statements in Velato begin with a "command root" note; intervals from this note are translated into commands and expressions. The command root can be changed between statements, to allow for more musical (or at least less repetitive) progressions. Notes played as chords are interpreted in the order the notes appear within the MIDI track, regardless of a zero duration between them.
All statements begin with the current command root, and are followed by one of these sequences of notes:
|Command||Second note||Third note||Followed by / Notes|
|Change Root Note||Major 2nd||New root note|
|Let (assignment)||Minor 3rd||Variable as single note, then expression|
|Declare variable||Minor 6th||Variable as single note, then type|
|End While||Perfect 4th|
|End If||Major 7th|
|Special Commands||Major 6th|
|Print to screen||Perfect 5th||Expression to print|
Commands can be followed by any number of expressions. Notes used for expressions don't differentiate between major/minor or perfect/diminished. To avoid ambiguity, no augmented intervals can be used. So a tritone is always interpreted as a diminished 5th, not an augmented 4th.
|Expression||First note||Second note||Third note||Followed by / Notes|
|variable||2nd||Name of variable (single note)|
|pos. (+) int||5th||Single note for each digit, ending with Perfect 5th to mark end of number|
|neg. (-) int||3rd||Single note for each digit, ending with Perfect 5th to mark end of number|
|char||4th||Char as ASCII int: single note for each digit, ending with Perfect 5th to mark end of number|
|pos. (+) double||6th||Single note for each digit, first Perfect 5th to mark decimal point, second Perfect 5th marking end of number|
|neg. (-) double||7th||Single note for each digit, first Perfect 5th to mark decimal point, second Perfect 5th marking end of number|
|NOT||5th||Also used for NOT < (indicating greater than or equal to) and NOT =|
|exponential / other||7th|
int = 2nd
char = 3rd
double = 4th
This is a sheet music representation of one possible "Hello, World" program:
Keep in mind that the order the concurrent notes in this representation appear in the actual MIDI file will affect the program.
Musical notes, another esolang based on music.