Velato

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.

Language overview

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.

Commands

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
Blocks	Major 3rd
While		Major 3rd	Expression
End While		Perfect 4th
If		Perfect 5th	Expression
Else		Major 6th
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
value	3rd
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
conditional	2nd
=		2nd
>		3rd
<		4th
NOT		5th		Also used for NOT < (indicating greater than or equal to) and NOT =
AND		6th
OR		7th
procedural	6th
grouping		6th
(			6th
)			2nd
math operation	5th
simple		5th
+			3rd
-			2nd
*			5th
/			4th
% (mod)			6th
exponential / other		7th
power			2nd
log			3rd

Types:

int = 2nd
char = 3rd
double = 4th

Examples

Hello, world!

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.

External resources

• [1] .NET Velato compiler
• [2] Accordion March of the Data Transmission: recording of a Velato program that copies input to output
• [3] "Hello, World" source code in MIDI format
• [4] "Hello, World" MIDI source code converted into a jazzy MP3
• [5] Tutorial on constructing a "Hello, World" program