Another round of optimization

crates/forth/src/types.rs

@@ -22,7 +22,7 @@ pub struct ExecutionTrace {
     pub selected_spans: Vec<SourceSpan>,
 }
 
-pub struct StepContext {
+pub struct StepContext<'a> {
     pub step: usize,
     pub beat: f64,
     pub bank: usize,
@@ -36,6 +36,8 @@ pub struct StepContext {
     pub fill: bool,
     pub nudge_secs: f64,
     pub cc_access: Option<Arc<dyn CcAccess>>,
+    pub speed_key: &'a str,
+    pub chain_key: &'a str,
     #[cfg(feature = "desktop")]
     pub mouse_x: f64,
     #[cfg(feature = "desktop")]
@@ -44,7 +46,7 @@ pub struct StepContext {
     pub mouse_down: f64,
 }
 
-impl StepContext {
+impl StepContext<'_> {
     pub fn step_duration(&self) -> f64 {
         60.0 / self.tempo / 4.0 / self.speed
     }
@@ -138,6 +140,14 @@ pub(super) struct CmdRegister {
 }
 
 impl CmdRegister {
+    pub(super) fn new() -> Self {
+        Self {
+            sound: None,
+            params: Vec::with_capacity(16),
+            deltas: Vec::with_capacity(4),
+        }
+    }
+
     pub(super) fn set_sound(&mut self, val: Value) {
         self.sound = Some(val);
     }

crates/forth/src/vm.rs

@@ -70,8 +70,8 @@ impl Forth {
         trace: Option<&mut ExecutionTrace>,
     ) -> Result<Vec<String>, String> {
         let mut stack = self.stack.lock().unwrap();
-        let mut outputs: Vec<String> = Vec::new();
-        let mut cmd = CmdRegister::default();
+        let mut outputs: Vec<String> = Vec::with_capacity(8);
+        let mut cmd = CmdRegister::new();
 
         self.execute_ops(ops, ctx, &mut stack, &mut outputs, &mut cmd, trace)?;
 
@@ -148,8 +148,8 @@ impl Forth {
                 return Err("stack underflow".into());
             }
             let start = stack.len() - count;
-            let values: Vec<Value> = stack.drain(start..).collect();
-            let selected = values[idx].clone();
+            let selected = stack[start + idx].clone();
+            stack.truncate(start);
             select_and_run(selected, stack, outputs, cmd)
         };
 
@@ -718,11 +718,10 @@ impl Forth {
                 Op::SetSpeed => {
                     let speed = stack.pop().ok_or("stack underflow")?.as_float()?;
                     let clamped = speed.clamp(0.125, 8.0);
-                    let key = format!("__speed_{}_{}__", ctx.bank, ctx.pattern);
                     self.vars
                         .lock()
                         .unwrap()
-                        .insert(key, Value::Float(clamped, None));
+                        .insert(ctx.speed_key.to_string(), Value::Float(clamped, None));
                 }
 
                 Op::Chain => {
@@ -734,9 +733,10 @@ impl Forth {
                     if bank as usize == ctx.bank && pattern as usize == ctx.pattern {
                         // chaining to self is a no-op
                     } else {
-                        let key = format!("__chain_{}_{}__", ctx.bank, ctx.pattern);
-                        let val = format!("{bank}:{pattern}");
-                        self.vars.lock().unwrap().insert(key, Value::Str(Arc::from(val), None));
+                        use std::fmt::Write;
+                        let mut val = String::with_capacity(8);
+                        let _ = write!(&mut val, "{bank}:{pattern}");
+                        self.vars.lock().unwrap().insert(ctx.chain_key.to_string(), Value::Str(Arc::from(val), None));
                     }
                 }
 
@@ -1010,36 +1010,57 @@ fn emit_output(
     nudge_secs: f64,
     outputs: &mut Vec<String>,
 ) {
-    let mut pairs: Vec<(String, String)> = if let Some(s) = sound {
-        vec![("sound".into(), s.to_string())]
-    } else {
-        vec![]
-    };
-    pairs.extend(params.iter().cloned());
-    if nudge_secs > 0.0 {
-        pairs.push(("delta".into(), nudge_secs.to_string()));
+    use std::fmt::Write;
+    let mut out = String::with_capacity(128);
+    out.push('/');
+
+    let has_dur = params.iter().any(|(k, _)| k == "dur");
+    let delaytime_idx = params.iter().position(|(k, _)| k == "delaytime");
+
+    if let Some(s) = sound {
+        let _ = write!(&mut out, "sound/{s}");
     }
-    // Only add default dur if there's a sound (new voice)
-    if sound.is_some() && !pairs.iter().any(|(k, _)| k == "dur") {
-        pairs.push(("dur".into(), step_duration.to_string()));
-    }
-    // Only add default delaytime if there's a sound (new voice)
-    if sound.is_some() {
-        if let Some(idx) = pairs.iter().position(|(k, _)| k == "delaytime") {
-            let ratio: f64 = pairs[idx].1.parse().unwrap_or(1.0);
-            pairs[idx].1 = (ratio * step_duration).to_string();
-        } else {
-            pairs.push(("delaytime".into(), step_duration.to_string()));
+
+    for (i, (k, v)) in params.iter().enumerate() {
+        if !out.ends_with('/') {
+            out.push('/');
         }
-    }
-    for pair in &mut pairs {
-        if is_tempo_scaled_param(&pair.0) {
-            if let Ok(val) = pair.1.parse::<f64>() {
-                pair.1 = (val * step_duration).to_string();
+        if is_tempo_scaled_param(k) {
+            if let Ok(val) = v.parse::<f64>() {
+                let _ = write!(&mut out, "{k}/{}", val * step_duration);
+                continue;
             }
         }
+        if Some(i) == delaytime_idx && sound.is_some() {
+            let ratio: f64 = v.parse().unwrap_or(1.0);
+            let _ = write!(&mut out, "{k}/{}", ratio * step_duration);
+        } else {
+            let _ = write!(&mut out, "{k}/{v}");
+        }
     }
-    outputs.push(format_cmd(&pairs));
+
+    if nudge_secs > 0.0 {
+        if !out.ends_with('/') {
+            out.push('/');
+        }
+        let _ = write!(&mut out, "delta/{nudge_secs}");
+    }
+
+    if sound.is_some() && !has_dur {
+        if !out.ends_with('/') {
+            out.push('/');
+        }
+        let _ = write!(&mut out, "dur/{step_duration}");
+    }
+
+    if sound.is_some() && delaytime_idx.is_none() {
+        if !out.ends_with('/') {
+            out.push('/');
+        }
+        let _ = write!(&mut out, "delaytime/{step_duration}");
+    }
+
+    outputs.push(out);
 }
 
 fn perlin_grad(hash_input: i64) -> f64 {
@@ -1116,11 +1137,6 @@ where
     Ok(())
 }
 
-fn format_cmd(pairs: &[(String, String)]) -> String {
-    let parts: Vec<String> = pairs.iter().map(|(k, v)| format!("{k}/{v}")).collect();
-    format!("/{}", parts.join("/"))
-}
-
 fn resolve_cycling(val: &Value, emit_idx: usize) -> Cow<'_, Value> {
     match val {
         Value::CycleList(items) if !items.is_empty() => {