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content/mimiumの配列実装.md

@@ -77,3 +77,46 @@ impl Machine{
 }
 
 ```
+
+
+## 用途
+
+例えばcatさんに作ってもらったこの辺の再帰を用いたコードがあるとする
+
+```rust
+fn gen_metalic_rec(times,freq,oscproto){
+  if(times>0){
+    let next = gen_metalic_rec(times-1,freq*1.176,oscproto)
+    let osc = oscproto();
+    | | { osc(freq) + next() }
+  }else{
+    | | 0.0
+  }
+}
+fn gen_metalic(times,freq){
+  let gen = gen_metalic_rec(times,freq,| | square_0);
+  | | gen() / times
+}
+let lowest_freq = 200.0
+let myoscbank = gen_metalic(6,lowest_freq)
+```
+
+こういう組み込み関数を与えて、
+
+```rust
+extern enumerate_by: (times,init:float,(x:float,acc:float)->float)->[float]
+```
+
+```rust
+
+fn metalic(times,lowest_freq){
+  let freqs =  enumerate_by(times,lowest_freq, |_x,acc| acc*1.167)
+  let res = map(freqs,|f| `square_0(liftf(f)))
+	        |> foldl(_, |x,acc| `{ $x + $acc } )
+  `{$res / liftf(times)}
+}
+fn dsp(){
+  metalic!(6,200)
+}
+
+```