Code structure

Omni files can have two different extensions: .omni or .oi.

Omni files are divided into different block statements. A simple sinusoidal oscillator can be expressed as simply as this:

ins:  1
outs: 1

    phase = 0

    freq_incr = in1 / samplerate
    out1 = sin(phase * TWOPI)
    phase = (phase + freq_incr) % 1

In the previous oscillator example, the ins and outs blocks define the number of inputs and outputs of the algorithm. The init block defines the initialization of variables whose state is store and preserved in the sample block, which implement the algorithm sample by sample. The in1 and out1 variables are dynamically created by omni to represent the input and output values at the current sample, as described by the ins and outs statements.

It is important to remember that ALL code must always be included inside of each of the different blocks, each one serving a different purpose. More information on all the block types follows in the next sections.


In omni, indentation is mandatory to specify each different block section.

Variable declaration

As you might have noticed, declaration of variables in omni doesn’t need any keyword. Despite being a strictly statically typed language, all types are inferred by the return type of a given statement. Optionally, types can be explicitly set with this syntax:

    phase float = 0.0

For number types, if not specified otherwise, all variables are declared as float. In this regards, int types are considered “second class citizens”, and need to be explicitly declared.

    phase      = 0      #float
    phase2 int = 0      #int
    test       = true   #bool, booleans are not affected by this mechanism

All variables of standard types, excluding the ones assigned to an instantiation of a struct (more on them later), are modifiable. To declare a non-modifiable variable, declare it with all upper cases:

    PHASE = 0.0
    PHASE = 1.0  # <-- This will error out, trying to modify a constant variable

Function calls

The syntax to call functions, defs (more on them later), can be either of the following:

def mySum(a, b):
    return a + b

    a = 1
    b = 2
    x = mySum(a, b) #standard calling syntax
    y = a.mySum(b)  #alternative "method" calling syntax

Flow control

There are two options for loops in omni, using either the for or while statements:

    #This counts from 0 to 10
    for i in 0..10:

    #This counts from 0 to 9
    for i in 0..<10:

    i = 0
    while i < 10:
        i += 1

As for conditionals, the standard if / elif / else are provided. Note also that, just as in the nim programming language, it is possible to assign the result of a conditional statement to a variable:

    a = 10
    b = 20

    if a < b:
        print("less then")
    elif a > b:
        print("more then")

    c = if a < b: a else: b


if, elif, else, case, for, while, mod, and, or, not, float, float32, float64, int, int32, int64, def, struct, samplerate, bufsize, ins, outs, in[1..32], out[1..32], init, build, perform, sample, Data, Delay, Buffer, signal, signal32, signal64, sig, sig32, sig64


  1. float defaults to the bits of your machine. So, on a 64bit computer, float is equal to float64
  2. signal and sig are equal to float (and, conversely, signal32 and sig32 are equal float32, signal64 / sig64 to float64)

Next: 02 - The ins and outs blocks