From 9a4c970b9558d11bb47c131fe31d11466bbab1b8 Mon Sep 17 00:00:00 2001
From: Miika Alonen <amiika@gmail.com>
Date: Sun, 19 Feb 2023 22:56:11 +0200
Subject: [PATCH] Added euclidean evaluation

---
 ziffers/classes.py | 51 ++++++++++++++++++++++++++++++++++++++++++----
 ziffers/common.py  | 20 ++++++++++++++++++
 ziffers/mapper.py  |  4 ++--
 3 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/ziffers/classes.py b/ziffers/classes.py
index b9a2845..fefc8e7 100644
--- a/ziffers/classes.py
+++ b/ziffers/classes.py
@@ -5,6 +5,7 @@ import operator
 import random
 from .defaults import DEFAULT_OPTIONS
 from .scale import note_from_pc, midi_to_pitch_class, midi_to_freq, get_scale_length
+from .common import euclidian_rhythm
 
 
 @dataclass(kw_only=True)
@@ -326,6 +327,8 @@ class Sequence(Meta):
                     yield from item.evaluate_tree(options)
             elif isinstance(item, Cyclic):
                 yield from _resolve_item(item.get_value(), options)
+            elif isinstance(item, Euclid):
+                yield from _euclidean_items(item, options)
             elif isinstance(item, Modification):
                 options = _update_options(item, options)
             elif isinstance(item, Meta):  # Filters whitespace
@@ -362,6 +365,13 @@ class Sequence(Meta):
                 for item in tree:
                     yield from _resolve_item(item, options)
 
+        def _euclidean_items(euclid: Item, options: dict):
+            """Repeats items with the same random values"""
+            euclid.evaluate(options)   
+            for item in euclid.evaluated_values:
+                yield from _resolve_item(item, options)
+
+
         def _update_options(current: Item, options: dict) -> dict:
             """Update options based on current item"""
             if isinstance(current, (OctaveChange, DurationChange)):
@@ -727,7 +737,9 @@ class ListOperation(Sequence):
                 (right.values if isinstance(right, Sequence) else [right]), left
             )
             left = [
-                Pitch(pitch_class=operation(x.get_value(), y.get_value()), kwargs=options)
+                Pitch(
+                    pitch_class=operation(x.get_value(), y.get_value()), kwargs=options
+                )
                 for (x, y) in pairs
             ]
         return left
@@ -767,9 +779,40 @@ class Euclid(Item):
 
     pulses: int
     length: int
-    onset: list
-    offset: list = field(default=None)
-    rotate: int = field(default=None)
+    onset: ListSequence
+    offset: ListSequence = field(default=None)
+    rotate: int = field(default=0)
+    evaluated_values: list = field(default=None)
+
+    def evaluate(self, options):
+        onset_values = [
+            val for val in self.onset.values if not isinstance(val, Whitespace)
+        ]
+        onset_length = len(onset_values)
+        booleans = euclidian_rhythm(self.pulses, self.length, self.rotate)
+        self.evaluated_values = []
+
+        if self.offset is not None:
+            offset_values = [
+                val for val in self.offset.values if not isinstance(val, Whitespace)
+            ]
+            offset_length = len(offset_values)
+
+        on_i = 0
+        off_i = 0
+
+        for i in range(self.length):
+            if booleans[i]:
+                value = onset_values[on_i % onset_length]
+                on_i+=1
+            else:
+                if self.offset is None:
+                    value = Rest(duration=options["duration"])
+                else:
+                    value = offset_values[off_i % offset_length]
+                off_i+=1
+
+            self.evaluated_values.append(value)
 
 
 @dataclass(kw_only=True)
diff --git a/ziffers/common.py b/ziffers/common.py
index 93bc955..d74529a 100644
--- a/ziffers/common.py
+++ b/ziffers/common.py
@@ -53,3 +53,23 @@ def string_rewrite(axiom: str, rules: dict):
 
     pattern = re.compile("|".join(rules.keys()))
     return pattern.sub(lambda m: next(_apply_rules(m)), axiom)
+
+
+def euclidian_rhythm(pulses: int, length: int, rotate: int = 0):
+    """Calculate Euclidean rhythms. Original algorithm by Thomas Morrill."""
+
+    def _starts_descent(list, index):
+        length = len(list)
+        next_index = (index + 1) % length
+        return list[index] > list[next_index]
+
+    def rotation(l, n):
+        return l[-n:] + l[:-n]
+
+    if pulses >= length:
+        return [True]
+
+    res_list = [pulses * t % length for t in range(-1, length - 1)]
+    bool_list = [_starts_descent(res_list, index) for index in range(length)]
+
+    return rotation(bool_list, rotate)
diff --git a/ziffers/mapper.py b/ziffers/mapper.py
index eb7b875..931842d 100644
--- a/ziffers/mapper.py
+++ b/ziffers/mapper.py
@@ -340,10 +340,10 @@ class ZiffersTransformer(Transformer):
     def euclid(self, items):
         """Parse euclid notation"""
         params = items[1][1:-1].split(",")
-        init = {"onset": items[0], "pulses": params[0], "length": params[1]}
+        init = {"onset": items[0], "pulses": int(params[0]), "length": int(params[1])}
         text = items[0].text + items[1]
         if len(params) > 2:
-            init["rotate"] = params[2]
+            init["rotate"] = int(params[2])
         if len(items) > 2:
             init["offset"] = items[2]
             text = text + items[2].text