Velato is an esoteric programming language by User:Rottytooth, which uses MIDI files as source code. Programs in Velato 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.
The first note sounded in a Velato program is the "command root" note. All intervals are read from this note until a new command root is established. 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.
Command Intervals differentiate between major and minor intervals. Fourths and fifths are always perfect. Depending on the compiler used, other intervals return syntax errors or are ignored.
|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|
|Input||Major 6th||Variable to store string|
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 =|
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.
Compilers and Interpreters
- Velato site
- "Hello, World" source code in MIDI format
- "Hello, World" MIDI source code as MP3
- Hello World Tutorial
- Accordion March of the Data Transmission (from the Wayback Machine; retrieved on 29 May 2013): recording of a Velato program that copies input to output