From 964ee68974be4c8ea3a4da5bef79bf86d93ac95f Mon Sep 17 00:00:00 2001
From: Bradford Powell <bpow@unc.edu>
Date: Fri, 29 Jul 2022 12:44:56 -0400
Subject: [PATCH] implement "?" operator in minilanguage (for degradeBy)

this will require update to krill-parser.js (aggregated
in later commit) to work properly
---
 packages/mini/krill.pegjs | 5 ++++-
 packages/mini/mini.mjs    | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/mini/krill.pegjs b/packages/mini/krill.pegjs
index 5451cf01..e266c395 100644
--- a/packages/mini/krill.pegjs
+++ b/packages/mini/krill.pegjs
@@ -102,7 +102,7 @@ slice = step / sub_cycle  / timeline
 
 // slice modifier affects the timing/size of a slice (e.g. [a b c]@3)
 // at this point, we assume we can represent them as regular sequence operators
-slice_modifier = slice_weight / slice_bjorklund / slice_slow / slice_fast / slice_fixed_step / slice_replicate
+slice_modifier = slice_weight / slice_bjorklund / slice_slow / slice_fast / slice_fixed_step / slice_replicate / slice_degrade
 
 slice_weight =  "@" a:number
   { return { weight: a} }
@@ -122,6 +122,9 @@ slice_fast = "*"a:number
 slice_fixed_step = "%"a:number
   { return { operator : { type_: "fixed-step", arguments_ :{ amount:a } } } }
 
+slice_degrade = "?"a:number?
+  { return { operator : { type_: "degradeBy", arguments_ :{ amount:(a? a : 0.5) } } } }
+
 // a slice with an modifier applied i.e [bd@4 sd@3]@2 hh]
 slice_with_modifier = s:slice o:slice_modifier?
   { return new ElementStub(s, o);}
diff --git a/packages/mini/mini.mjs b/packages/mini/mini.mjs
index 20971230..684616ff 100644
--- a/packages/mini/mini.mjs
+++ b/packages/mini/mini.mjs
@@ -21,6 +21,8 @@ const applyOptions = (parent) => (pat, i) => {
         return reify(pat).fast(speed);
       case 'bjorklund':
         return pat.euclid(operator.arguments_.pulse, operator.arguments_.step, operator.arguments_.rotation);
+      case 'degradeBy':
+        return reify(pat)._degradeByWith(strudel.rand.early(0.0001 * _nextSeed()).segment(1), operator.arguments_.amount);
       // TODO: case 'fixed-step': "%"
     }
     console.warn(`operator "${operator.type_}" not implemented`);