Patterns are questions about time.

A pattern answers a question about an interval instead of stepping through a list that is consumed once. Mora calls that operation events-in. A span is half-open: it includes its beginning and excludes its end. Time is expressed in cycles, and fractions such as 1/3 and 7/8 can remain exact Common Lisp ratios.

A cycle is a musical coordinate, not intrinsically a second or a bar. The transport maps it to physical time using tempo and beats per cycle. With four beats per cycle, 140 BPM corresponds to 7/12 cycles per second, so these two forms express the same rate:

Visible spans and whole events. A scheduler may query only a fragment of a note or loop. That query should not turn the fragment into a new full event, change a recording's pitch, or create another attack by accident. An onset belongs to the event's temporal identity, which is why score-time looping, audio-file looping, and changing a sample's playback speed are separate operations.

Patterns and time

Mini notation is compact temporal notation inside strings. It is embedded in Common Lisp rather than replacing it. The literal forms s, n, notes, p, and e are macros with context-sensitive coercion: inside s, bare symbols can mean sample names.

Use sub to subdivide a slot directly in s-expressions:

Use ($ expression) when a literal should evaluate ordinary Lisp. Functions, variables, and control structures remain available; a list is ordinary Lisp data unless it is explicitly turned into a pattern.

>> threads a pattern through transformations and clauses from left to right. Use stack for simultaneous voices. Parallel voices are not parameter merging: annotations such as gain use merge-left, so each existing event keeps its multiplicity while receiving its parameter. The open pattern-merge-style protocol selects that behavior.

time-cat weights are proportions; arrange allocates actual cycle durations. A Mora channel owns a source pattern, while a SuperDirt orbit is an output bus, so one stack can route its lanes to separate orbits.

Pipelines and composition

Temporal transformations act on score time. Audio-file parameters act on the resulting sound: rev reverses a score, while sample-rev reverses sample playback. The supplied chance operators are temporally reproducible, rather than consulting global random state on every scheduler fragment.

Named pitches, scale degrees, chords and voicings, arpeggiation, tuning beyond twelve equal divisions, and authored meter are part of the language. Chord identity and its realization as voices are separate, and arpeggiate selects actual voices from those chords.

Authored positions are not the same as emitted attacks: rests count as positions. pace retimes a phrase according to authored units, separately from global BPM. Here the three-unit and five-unit phrases occupy 3/4 and 5/4 cycles at four units per cycle, with consistent unit spacing instead of squeezing each phrase into an equal duration.

Consider a composition made from a sample sequence and a speed change, like the one below. The source is a convenient way to construct it, but the result is not limited to source text. Named pattern instances, their children, metadata, and applicable methods remain available for inspection and interpretation.

Common Lisp is not only a notation host for Mora; it supplies the working environment in which the language is developed and performed. In CLOS, a generic function can have methods specialized for different classes. Mora uses this to separate temporal interpretation, structural observation, construction, composition policy, and shader emission, so an extension can implement the operation it actually needs.

Mora chooses named classes and generic operations so representation, strategy, and state can be inspected and specialized in the running image.

The openness is bounded. Not every intermediate construction object is retained, not every custom extension automatically gains every editor affordance, and a new interpretation may apply only to a particular class family.

Common Lisp and CLOS

defpattern defines a named pattern class, constructor, and observation and query methods. The class generated here is pulse-pattern, with a pulse-factor reader.

An applicable method can change the behavior of the same object on subsequent queries:

The defpattern body is evaluated by its query method, not once as a universal compile step, so keep it suitable for repeated arbitrary-span interpretation. deftransform defines a reusable, inspectable transformation, and musical vocabularies such as scales can be extended as well:

Mora is SBCL-first Common Lisp. Its scheduler and backends are separate from the notation layer, and Studio's editor and evaluation model is separate from its native GL renderer. Visual operators are pattern objects with an adjacent GLSL interpretation for that subset.