x Trigger Notation

In Roll You Own Syntax, I theorized how users could construct their own systems of notation using strings. I’ve constructed a working function, called trig(), to show how it’s done.

First, let’s see trig() in action. The following is complete conceptual prototype Slipmat program that generates a rock drum groove with 8th note hats:

#!/usr/bin/env slipmat

from JakeLib.Generators import trig
from EasyKit import hat, snare, kick
@trig('x.x. x.x. x.x. x.x.') hat()
@trig('.... x... .... x...') snare()
@trig('x... .... x... ....') kick()

This horizontal system for notating triggers, and others like it, can greatly improve the legibility of a piece, while catering to a composer’s preferred style of working. A composer quickly scans this and comprehends it without having to reconstruct it in their head from a list of individual events:

@0    hat()
@0    kick()
@0.5  hat()
@1    hat()
@1    snare()
@1.5  hat()
@2    hat()
@2    kick()
@2.5  hat()
@3    hat()
@3    snare()
@3.5  hat()

The form is lost in translation.

Building the function is pretty straight forward if you’re somewhat experienced with Python. I put together the following function definition, with docstrings, in roughly 15 minutes:

def trig(seq, res=0.25):
    Creates a numeric sequence from a string and returns a list.

    A string trigger sequencer, where an 'x' creates a trigger, and a
    '.' creates a rest. All other glyphs are ignored. The resolution
    of triggers and rests are determined by the argument res.

    seq -- A string containing a sequence of 'x' triggers and '.' rests
    res -- Resolution of note triggers and rests
    return -- A numeric list
    L = []  # The return list
    p = 0   # Position in sequence

    for c in seq:
        if c == 'x':
            L.append(p * res)
            p += 1            
        elif c == '.':
            p += 1

    return L

The trig() function accepts a string formatted in what I call ‘x trigger notation.’ The function parses the string and auto-generates a list of numbers representing trigger times. A trigger is denoted by an ‘x’, while a rest is a ‘.’. All other glyphs are ignored. I use a single space between beats for clarity. The default resolution is a 16th note, though trig() accepts an optional argument for changing the resolution, increasing its usefulness.

Import, Reuse, Remix

The best part about custom functions is that they can be reused multiple times in multiple programs by multiple people with the use of the import. No refactoring of code, no copy and paste, no reinventing of the wheel. Just import, reuse, remix.

Roll Your Own Score Syntax

A music language that comes with a fully-loaded set of string capabilities, including regular expressions, would allow users to develop their own methods for notating music. For example, here is a horizontal representation for rhythm guitar.

@0  strum('C',  '/... /... /./. /...')
@4  strum('Dm', '/... /... //// /./.')
@8  strum('G7', '/... /... ///. ../.')
@12 strum('C',  '/... /... /... ///.')

The slash triggers an event and advances time by a 16th note. The dot just advances time by a 16th note. A space does nothing.

These 4 lines of code represent 24 events. Not only does this shorten the score and save keystrokes, but is far more readable than if each individual event was explicitly written. In fact, I bet there are many guitar players out there that could play this as it’s written, providing he or she was given a brief explanation about the notation.

What about a system for triggering drums? Here’s the all-to-familiar 4-beat rock pattern with 8th note hats.

trigger(hat(),   'x.x. x.x. x.x. x.x.')
trigger(snare(), '.... x... .... x...')
trigger(kick(),  'x... .... x... ....')

Once again, the music is notated horizontally. Instead of 12 lines of code, there are only 3. Let’s take a look at the vertical equivalent:

@0   hat()
@0   kick()
@0.5 hat()
@1   hat()
@1   snare()
@1.5 hat()
@2   hat()
@2   kick()
@2.5 hat()
@3   hat()
@3   snare()
@3.5 hat()

In theory, people could write slipmat modules that mimic other text-based notation systems, such as the Csound score language.

import CsoundScore as CS
from MyLibrary import bassFM
from MyLibrary import pad

# For mapping slipmat instruments to a Csound-styled score
instrs = {"i1": bassFM(), "i2": pad()}

# A Csound-styled score
score = '''
i 1 0 2 0.5 7.00
i 1 + . .   6.05

i 2 0 8 0.333 8.09 0.77 1000

CS.playScore(instrs, score)  # Play Csound-styled score

That would translate to:

@0 bassFM(2, 0.5, 7.00)
@2 bassFM(2, 0.5, 6.05)
@0 pad(8, 0.333, 8.09, 0.77, 1000)

Much of this can be done with some of the existing music languages out in the wild. The guitar strum and drum trigger examples can be accomplished in pure Csound code (see dseq — A Drum Machine Micro-Language). Even more so, Csound combined with the Python API can do some truly amazing things along these lines. Though it probably wouldn’t be nearly as fluid as a language that had this in mind when being designed from the ground up.

If you haven’t done so yet, take a moment to ponder the possibilities. And be sure to think about the things others will dream up that can be simply imported into your own compositions/synthesizers/sequencers/etc…