Examples

1. dsp
2. “self” example
3. a simple effect
4. composition
5. sol-fa
6. rhythm pattern

Example: sol-fa

In the example below, the system’s audio driver sample rate is 48000 Hz, and it will play sol-fa sounds every second.

notes = [440,495,260.7,293.3,330,347.7,391.1]
index = 0
fn updateIndex(){
  index = (index+1)%7
  updateIndex()@(now+48000)
}
updateIndex()@48000
fn dsp(){
 vol = 0.2
 octave = 1
 sec = now/48000
 freq = notes[index]
 out = vol * sin(octave*freq*3.14*2*sec)
 return (0,out)
}

Point 1: Arrays.

notes = [440,495,260.7,293.3,330,347.7,391.1] // 1st line

In mimium, you can define an array. Arrays are defined using []. The beginning of the index is 0. In this example, the first line of the array that creates the sol-fa sounds note contains the frequencies of the A-B-C-D-E-F-G notes, which are used in subsequent processing.

• A: 440Hz
• B: 495Hz
• C: 260.7Hz
• D: 293.3Hz
• E: 330Hz
• F: 347.7Hz
• G: 391.1Hz

The way to use arrays is to use array_name[index], as in line 12. freq = notes[index] // line 12.

Point 2: Temporal Recursion

// Lines 3~7
fn updateIndex(){
  index = (index+1)%7
  updateIndex()@(now+48000)
}
updateIndex()@48000

V0.3.0 does not adopt the for-loop statement that most languages have. However, you can describe repetitive executions of the function by using a design pattern called temporal recursion as shown in lines 3~6. In the sol-fa example, after executing updateIndex() at 48000 samples in line 7, the now and @ keywords are used together in the function to execute updateIndex() at 48000 samples from the current time (line 5).

Point 3: Using the now and @ keywords together

updateIndex()@(now+48000) // line 5

In mimium, the current number of samples can be retrieved using now. Users should note that in the v0.3.0 current specification, the now keyword does not represent real-time. The unit is sample¹.

Also, mimium has a @ keyword, which means “execute the function before @ when the number of samples is the number of values resulting from the calculation of the expression after @.

The @ time indicates the absolute time since the audio driver was started, so if you write updateIndex()@48000 as in line 7, it will always execute updateIndex() once 48000 samples after it was started. In the fifth line of the example, by connecting now and 48000 with the + keyword, we can determine the sample point in time from the current time, and by using @, we can execute the function at that sample point.

Point 4: Octave

// Lines 8~15
fn dsp(){
 vol = 0.2
 octave = 1
 sec = now/48000
 freq = notes[index]
 out = vol  *sin(octave*freq*3.14*2*sec)
 return (0,out)
}

In the musical scale, there is a relationship between doubling the frequency (Hz) and going up an octave, and conversely, halving the frequency and going down an octave. In lines 8 to 15 of the example, the value is fixed at octave = 1, so it plays a sol-fa sounds from 260.7Hz to 495Hz, but if you change this value to 2, for example, you can express a scale that goes up an octave.