Introduction to Velato

Velato is a programming language which uses MIDI files as source code. Commands are determined by the intervals between notes.

Download Velato compiler for Windows.

Velato commands

All commands in Velato are expressed strictly by the pitch and order of notes. With the exception of variable names (more on this below), only the interval between notes is relevant, rather than the pitch itself.

The range of pitches is the alphabet in which Velato commands are written. This means that time signature, key signature, measures, rests, repeat marks, even note durations, are ignored by the code. If two notes are played as a chord, with no delay between the sounding of the notes, the one which appears first in the MIDI file is interpreted first, as if they had not been played simultaneously.

The commands and expressions themselves are determined by intervals from a command root note, which is the first note of the song. Therefore, a valid Velato program in one key can be translated to any other key, with no effect on the program. To allow versatility in Velato composition, the key can also be changed between any two commands within the song (using the "change command root" command). This allows the programmer to choose a starting pitch that better fits the flow of the song.

Also, additional tracks can be added to the MIDI file, which will be ignored by the compiler. This can allow any Velato program to be accompanied, without affecting the program.

For example: "C A G E D D", in the key of C, prints the variable D to the screen. In the key of G, the same command would be "G E D B A D". The actual definition of the print command are the set of intervals: Root (in the first case C), Major 6th (from root), Perfect 5th. The remaining three notes determine that it's variable D to print to the screen. Note that we did not transpose the final D, which is the name of the variable. For commands and expressions (except variables), octave is ignored, so an A in any octave has the same meaning. Also, notes are determined by pitch, not the actual written note, so G# and Ab are equivalent.

As mentioned above, variables are an exception. They are specific to octave and are not determined by interval; so command root changes do not affect them. This allows the program to have as many variables as there are notes allowed in the MIDI specification. This also makes programs less confusing to follow (having a different pitch for the same variable throughout a song would be confusing).


Commands

• Commands are made up of a series of notes.


• Commands can be of any length. All commands start with the Command Root.


• Intervals of the notes, following the command root, determine the command.


• Octave is ignored for commands (as is duration). So if a minor third from A is required, a C in any octave can be sounded.

The Command Root Note

• The command root note is not necessarily the root of the current key (or root of a chord).


• The command root note is defined by: the first note of the song, to begin with. Then, whenever the command is played twice in a row, the following note is the new command root.

Expressions

• Any notes from the end of a command to the beginning of the next are interpreted as an expression.

Numbers

• All numbers are assigned in base 10.


• Numbers are relative to the command root, and are not specific to an octave (so if a D represents a 1, it will do so in every octave).


• Command root is reserved for the end of the statement, and has no meaning in number assignment.


• One fifth above command root is end of int, or decimal point of double (second time would be end of double).


• All the other half steps from command root are digits of the number


• The next half-step up is zero, and numbers increment with each half-step, up to 9. At that point, we hit the command root in the next octave.


• For example:
  
  
  • if C is the command root, then the number sequence must end on a G (a perfect 5th up from the command root). Any G in the scale will suffice.
  
  
  • If this is a double, and we wish to use a decimal point, it is represented by the first G, while the second G completes the number.
  
  
  • Let's encode the number 458. Our command note is C, so four half-steps up is E. Five is F, and Seven is A. Then we finish on G to end the sequence.

Variables

• Any note can be a variable as well as a command, determined only by syntax.


• Variables can be assigned to any note.


• Variables can only be called by a command that does not start with (have a command root note) the same note as the variable note.


• So if the variable is assigned to Middle C, the command root note for the command calling it cannot be a C.


• A variable can be re-declared, erasing the value and type of the variable it is replacing.

Statements

• Statements in Velato always begin with the command root note, then a command, and then (in some cases) additional expressions.


• If an expression starts with the command root note, it is interpreted as a command, and will be matched to the Command List below.

Functions

• Functions are not yet implemented in Velato. They will work much like variables (in that they are represented by single notes, with no special meaning for interval or octave). They will be allowed to use the same "names" (pitches) as existing variables.

Other missing features

• Arrays (including arrays of char for strings), and a ReadLine() special command. Also, right now there is no method for handling input. I'm hoping to address these, plus improve the error messages version 0.2.

The following blog post will list all Velato commands.