Feat: improve 'at' in cagire grammar

crates/forth/src/compiler.rs

@@ -176,6 +176,13 @@ fn compile(tokens: &[Token], dict: &Dictionary) -> Result<Vec<Op>, String> {
                         ops.push(Op::Branch(else_ops.len()));
                         ops.extend(else_ops);
                     }
+                } else if word == "at" {
+                    if let Some((body_ops, consumed)) = compile_at(&tokens[i + 1..], dict)? {
+                        i += consumed;
+                        ops.push(Op::AtLoop(Arc::from(body_ops)));
+                    } else if !compile_word(word, Some(*span), &mut ops, dict) {
+                        return Err(format!("unknown word: {word}"));
+                    }
                 } else if word == "case" {
                     let (case_ops, consumed) = compile_case(&tokens[i + 1..], dict)?;
                     i += consumed;
@@ -355,6 +362,37 @@ fn compile_if(
     Ok((then_ops, else_ops, then_pos + 1, then_span, else_span))
 }
 
+fn compile_at(tokens: &[Token], dict: &Dictionary) -> Result<Option<(Vec<Op>, usize)>, String> {
+    let mut depth = 1;
+
+    enum AtCloser { Dot, MidiDot, Done }
+    let mut found: Option<(usize, AtCloser)> = None;
+
+    for (i, tok) in tokens.iter().enumerate() {
+        if let Token::Word(w, _) = tok {
+            match w.as_str() {
+                "at" => depth += 1,
+                "." if depth == 1 => { found = Some((i, AtCloser::Dot)); break; }
+                "m." if depth == 1 => { found = Some((i, AtCloser::MidiDot)); break; }
+                "done" if depth == 1 => { found = Some((i, AtCloser::Done)); break; }
+                "." | "m." | "done" => depth -= 1,
+                _ => {}
+            }
+        }
+    }
+
+    let Some((pos, closer)) = found else {
+        return Ok(None);
+    };
+    let mut body_ops = compile(&tokens[..pos], dict)?;
+    match closer {
+        AtCloser::Dot => body_ops.push(Op::Emit),
+        AtCloser::MidiDot => body_ops.push(Op::MidiEmit),
+        AtCloser::Done => {}
+    }
+    Ok(Some((body_ops, pos + 1)))
+}
+
 fn compile_case(tokens: &[Token], dict: &Dictionary) -> Result<(Vec<Op>, usize), String> {
     let mut depth = 1;
     let mut endcase_pos = None;

crates/forth/src/ops.rs

@@ -110,7 +110,8 @@ pub enum Op {
     ClearCmd,
     SetSpeed,
     At,
-    Arp,
+    AtLoop(Arc<[Op]>),
+
     IntRange,
     StepRange,
     Generate,

crates/forth/src/types.rs

@@ -96,7 +96,7 @@ pub enum Value {
     Str(Arc<str>, Option<SourceSpan>),
     Quotation(Arc<[Op]>, Option<SourceSpan>),
     CycleList(Arc<[Value]>),
-    ArpList(Arc<[Value]>),
+
 }
 
 impl PartialEq for Value {
@@ -107,7 +107,7 @@ impl PartialEq for Value {
             (Value::Str(a, _), Value::Str(b, _)) => a == b,
             (Value::Quotation(a, _), Value::Quotation(b, _)) => a == b,
             (Value::CycleList(a), Value::CycleList(b)) => a == b,
-            (Value::ArpList(a), Value::ArpList(b)) => a == b,
+
             _ => false,
         }
     }
@@ -143,7 +143,7 @@ impl Value {
             Value::Float(f, _) => *f != 0.0,
             Value::Str(s, _) => !s.is_empty(),
             Value::Quotation(..) => true,
-            Value::CycleList(items) | Value::ArpList(items) => !items.is_empty(),
+            Value::CycleList(items) => !items.is_empty(),
         }
     }
 
@@ -153,14 +153,14 @@ impl Value {
             Value::Float(f, _) => f.to_string(),
             Value::Str(s, _) => s.to_string(),
             Value::Quotation(..) => String::new(),
-            Value::CycleList(_) | Value::ArpList(_) => String::new(),
+            Value::CycleList(_) => String::new(),
         }
     }
 
     pub(super) fn span(&self) -> Option<SourceSpan> {
         match self {
             Value::Int(_, s) | Value::Float(_, s) | Value::Str(_, s) | Value::Quotation(_, s) => *s,
-            Value::CycleList(_) | Value::ArpList(_) => None,
+            Value::CycleList(_) => None,
         }
     }
 }
@@ -171,6 +171,7 @@ pub(super) struct CmdRegister {
     params: Vec<(&'static str, Value)>,
     deltas: Vec<Value>,
     global_params: Vec<(&'static str, Value)>,
+    delta_secs: Option<f64>,
 }
 
 impl CmdRegister {
@@ -180,6 +181,7 @@ impl CmdRegister {
             params: Vec::with_capacity(16),
             deltas: Vec::with_capacity(4),
             global_params: Vec::new(),
+            delta_secs: None,
         }
     }
 
@@ -237,9 +239,26 @@ impl CmdRegister {
         std::mem::take(&mut self.global_params)
     }
 
+    pub(super) fn set_delta_secs(&mut self, secs: f64) {
+        self.delta_secs = Some(secs);
+    }
+
+    pub(super) fn take_delta_secs(&mut self) -> Option<f64> {
+        self.delta_secs.take()
+    }
+
+    pub(super) fn clear_sound(&mut self) {
+        self.sound = None;
+    }
+
+    pub(super) fn clear_params(&mut self) {
+        self.params.clear();
+    }
+
     pub(super) fn clear(&mut self) {
         self.sound = None;
         self.params.clear();
         self.deltas.clear();
+        self.delta_secs = None;
     }
 }

crates/forth/src/vm.rs

@@ -241,31 +241,7 @@ impl Forth {
             sound_len.max(param_max)
         };
 
-        let has_arp_list = |cmd: &CmdRegister| -> bool {
-            matches!(cmd.sound(), Some(Value::ArpList(_)))
-                || cmd.global_params().iter().chain(cmd.params().iter())
-                    .any(|(_, v)| matches!(v, Value::ArpList(_)))
-        };
-
-        let compute_arp_count = |cmd: &CmdRegister| -> usize {
-            let sound_len = match cmd.sound() {
-                Some(Value::ArpList(items)) => items.len(),
-                _ => 0,
-            };
-            let param_max = cmd
-                .params()
-                .iter()
-                .map(|(_, v)| match v {
-                    Value::ArpList(items) => items.len(),
-                    _ => 0,
-                })
-                .max()
-                .unwrap_or(0);
-            sound_len.max(param_max).max(1)
-        };
-
         let emit_with_cycling = |cmd: &CmdRegister,
-                                 arp_idx: usize,
                                  poly_idx: usize,
                                  delta_secs: f64,
                                  outputs: &mut Vec<String>|
@@ -277,7 +253,7 @@ impl Forth {
                 return Err("nothing to emit".into());
             }
             let resolved_sound_val =
-                cmd.sound().map(|sv| resolve_value(sv, arp_idx, poly_idx));
+                cmd.sound().map(|sv| resolve_value(sv, poly_idx));
             let sound_str = match &resolved_sound_val {
                 Some(v) => Some(v.as_str()?.to_string()),
                 None => None,
@@ -286,8 +262,8 @@ impl Forth {
                 .iter()
                 .chain(cmd.params().iter())
                 .map(|(k, v)| {
-                    let resolved = resolve_value(v, arp_idx, poly_idx);
-                    if let Value::CycleList(_) | Value::ArpList(_) = v {
+                    let resolved = resolve_value(v, poly_idx);
+                    if let Value::CycleList(_) = v {
                         if let Some(span) = resolved.span() {
                             if let Some(trace) = trace_cell.borrow_mut().as_mut() {
                                 trace.selected_spans.push(span);
@@ -595,47 +571,17 @@ impl Forth {
                 }
 
                 Op::Emit => {
-                    if has_arp_list(cmd) {
-                        let arp_count = compute_arp_count(cmd);
+                    if let Some(dsecs) = cmd.take_delta_secs() {
                         let poly_count = compute_poly_count(cmd);
-                        let explicit_deltas = !cmd.deltas().is_empty();
-                        let delta_list: Vec<Value> = if explicit_deltas {
-                            cmd.deltas().to_vec()
-                        } else {
-                            Vec::new()
-                        };
-                        let count = if explicit_deltas {
-                            arp_count.max(delta_list.len())
-                        } else {
-                            arp_count
-                        };
-
-                        for i in 0..count {
-                            let delta_secs = if explicit_deltas {
-                                let dv = &delta_list[i % delta_list.len()];
-                                let frac = dv.as_float()?;
-                                if let Some(span) = dv.span() {
+                        for poly_idx in 0..poly_count {
+                            if let Some(sound_val) =
+                                emit_with_cycling(cmd, poly_idx, dsecs, outputs)?
+                            {
+                                if let Some(span) = sound_val.span() {
                                     if let Some(trace) = trace_cell.borrow_mut().as_mut() {
                                         trace.selected_spans.push(span);
                                     }
                                 }
-                                ctx.nudge_secs + frac * ctx.step_duration()
-                            } else {
-                                ctx.nudge_secs
-                                    + (i as f64 / count as f64) * ctx.step_duration()
-                            };
-                            for poly_i in 0..poly_count {
-                                if let Some(sound_val) =
-                                    emit_with_cycling(cmd, i, poly_i, delta_secs, outputs)?
-                                {
-                                    if let Some(span) = sound_val.span() {
-                                        if let Some(trace) =
-                                            trace_cell.borrow_mut().as_mut()
-                                        {
-                                            trace.selected_spans.push(span);
-                                        }
-                                    }
-                                }
                             }
                         }
                     } else {
@@ -657,7 +603,7 @@ impl Forth {
                                     }
                                 }
                                 if let Some(sound_val) =
-                                    emit_with_cycling(cmd, 0, poly_idx, delta_secs, outputs)?
+                                    emit_with_cycling(cmd, poly_idx, delta_secs, outputs)?
                                 {
                                     if let Some(span) = sound_val.span() {
                                         if let Some(trace) =
@@ -1196,12 +1142,60 @@ impl Forth {
                     cmd.set_deltas(deltas);
                 }
 
-                Op::Arp => {
+                Op::AtLoop(body_ops) => {
                     ensure(stack, 1)?;
-                    let values = std::mem::take(stack);
-                    stack.push(Value::ArpList(Arc::from(values)));
+                    let deltas = std::mem::take(stack);
+                    let n = deltas.len();
+
+                    for (i, delta_val) in deltas.iter().enumerate() {
+                        let frac = delta_val.as_float()?;
+                        let delta_secs = ctx.nudge_secs + frac * ctx.step_duration();
+
+                        let iter_ctx = StepContext {
+                            step: ctx.step,
+                            beat: ctx.beat,
+                            bank: ctx.bank,
+                            pattern: ctx.pattern,
+                            tempo: ctx.tempo,
+                            phase: ctx.phase,
+                            slot: ctx.slot,
+                            runs: ctx.runs * n + i,
+                            iter: ctx.iter,
+                            speed: ctx.speed,
+                            fill: ctx.fill,
+                            nudge_secs: ctx.nudge_secs,
+                            sr: ctx.sr,
+                            cc_access: ctx.cc_access,
+                            speed_key: ctx.speed_key,
+                            mouse_x: ctx.mouse_x,
+                            mouse_y: ctx.mouse_y,
+                            mouse_down: ctx.mouse_down,
+                        };
+
+                        cmd.set_delta_secs(delta_secs);
+
+                        let mut trace_opt = trace_cell.borrow_mut().take();
+                        let mut var_writes_guard = var_writes_cell.borrow_mut();
+                        let vw = var_writes_guard.as_mut().expect("var_writes taken");
+                        self.execute_ops(
+                            body_ops,
+                            &iter_ctx,
+                            stack,
+                            outputs,
+                            cmd,
+                            trace_opt.as_deref_mut(),
+                            vars_snapshot,
+                            vw,
+                        )?;
+                        drop(var_writes_guard);
+                        *trace_cell.borrow_mut() = trace_opt;
+
+                        cmd.clear_params();
+                        cmd.clear_sound();
+                    }
                 }
 
+
                 Op::Adsr => {
                     let r = pop(stack)?;
                     let s = pop(stack)?;
@@ -1499,35 +1493,13 @@ impl Forth {
 
                 // MIDI operations
                 Op::MidiEmit => {
+                    let at_loop_delta = cmd.take_delta_secs();
                     let (_, params) = cmd.snapshot().unwrap_or((None, &[]));
 
-                    // Build schedule: (arp_idx, poly_idx, delta_secs)
-                    let schedule: Vec<(usize, usize, f64)> = if has_arp_list(cmd) {
-                        let arp_count = compute_arp_count(cmd);
+                    // Build schedule: (poly_idx, delta_secs)
+                    let schedule: Vec<(usize, f64)> = if let Some(dsecs) = at_loop_delta {
                         let poly_count = compute_poly_count(cmd);
-                        let explicit = !cmd.deltas().is_empty();
-                        let delta_list = cmd.deltas();
-                        let count = if explicit {
-                            arp_count.max(delta_list.len())
-                        } else {
-                            arp_count
-                        };
-                        let mut sched = Vec::with_capacity(count * poly_count);
-                        for i in 0..count {
-                            let delta_secs = if explicit {
-                                let frac = delta_list[i % delta_list.len()]
-                                    .as_float()
-                                    .unwrap_or(0.0);
-                                ctx.nudge_secs + frac * ctx.step_duration()
-                            } else {
-                                ctx.nudge_secs
-                                    + (i as f64 / count as f64) * ctx.step_duration()
-                            };
-                            for poly_i in 0..poly_count {
-                                sched.push((i, poly_i, delta_secs));
-                            }
-                        }
-                        sched
+                        (0..poly_count).map(|pi| (pi, dsecs)).collect()
                     } else {
                         let poly_count = compute_poly_count(cmd);
                         let deltas: Vec<f64> = if cmd.deltas().is_empty() {
@@ -1542,7 +1514,6 @@ impl Forth {
                         for poly_idx in 0..poly_count {
                             for &frac in &deltas {
                                 sched.push((
-                                    0,
                                     poly_idx,
                                     ctx.nudge_secs + frac * ctx.step_duration(),
                                 ));
@@ -1551,14 +1522,14 @@ impl Forth {
                         sched
                     };
 
-                    for (arp_idx, poly_idx, delta_secs) in schedule {
+                    for (poly_idx, delta_secs) in schedule {
                         let get_int = |name: &str| -> Option<i64> {
                             params
                                 .iter()
                                 .rev()
                                 .find(|(k, _)| *k == name)
                                 .and_then(|(_, v)| {
-                                    resolve_value(v, arp_idx, poly_idx).as_int().ok()
+                                    resolve_value(v, poly_idx).as_int().ok()
                                 })
                         };
                         let get_float = |name: &str| -> Option<f64> {
@@ -1567,7 +1538,7 @@ impl Forth {
                                 .rev()
                                 .find(|(k, _)| *k == name)
                                 .and_then(|(_, v)| {
-                                    resolve_value(v, arp_idx, poly_idx).as_float().ok()
+                                    resolve_value(v, poly_idx).as_float().ok()
                                 })
                         };
                         let chan = get_int("chan")
@@ -1960,10 +1931,6 @@ where
     F: Fn(f64) -> f64 + Copy,
 {
     match val {
-        Value::ArpList(items) => {
-            let mapped: Result<Vec<_>, _> = items.iter().map(|x| lift_unary(x, f)).collect();
-            Ok(Value::ArpList(Arc::from(mapped?)))
-        }
         Value::CycleList(items) => {
             let mapped: Result<Vec<_>, _> = items.iter().map(|x| lift_unary(x, f)).collect();
             Ok(Value::CycleList(Arc::from(mapped?)))
@@ -1977,11 +1944,6 @@ where
     F: Fn(i64) -> i64 + Copy,
 {
     match val {
-        Value::ArpList(items) => {
-            let mapped: Result<Vec<_>, _> =
-                items.iter().map(|x| lift_unary_int(x, f)).collect();
-            Ok(Value::ArpList(Arc::from(mapped?)))
-        }
         Value::CycleList(items) => {
             let mapped: Result<Vec<_>, _> =
                 items.iter().map(|x| lift_unary_int(x, f)).collect();
@@ -1996,16 +1958,6 @@ where
     F: Fn(f64, f64) -> f64 + Copy,
 {
     match (a, b) {
-        (Value::ArpList(items), b) => {
-            let mapped: Result<Vec<_>, _> =
-                items.iter().map(|x| lift_binary(x, b, f)).collect();
-            Ok(Value::ArpList(Arc::from(mapped?)))
-        }
-        (a, Value::ArpList(items)) => {
-            let mapped: Result<Vec<_>, _> =
-                items.iter().map(|x| lift_binary(a, x, f)).collect();
-            Ok(Value::ArpList(Arc::from(mapped?)))
-        }
         (Value::CycleList(items), b) => {
             let mapped: Result<Vec<_>, _> =
                 items.iter().map(|x| lift_binary(x, b, f)).collect();
@@ -2045,11 +1997,8 @@ where
     Ok(())
 }
 
-fn resolve_value(val: &Value, arp_idx: usize, poly_idx: usize) -> Cow<'_, Value> {
+fn resolve_value(val: &Value, poly_idx: usize) -> Cow<'_, Value> {
     match val {
-        Value::ArpList(items) if !items.is_empty() => {
-            Cow::Owned(items[arp_idx % items.len()].clone())
-        }
         Value::CycleList(items) if !items.is_empty() => {
             Cow::Owned(items[poly_idx % items.len()].clone())
         }

crates/forth/src/words/compile.rs

@@ -88,7 +88,7 @@ pub(super) fn simple_op(name: &str) -> Option<Op> {
         "tempo!" => Op::SetTempo,
         "speed!" => Op::SetSpeed,
         "at" => Op::At,
-        "arp" => Op::Arp,
+
         "adsr" => Op::Adsr,
         "ad" => Op::Ad,
         "apply" => Op::Apply,

crates/forth/src/words/sequencing.rs

@@ -309,9 +309,9 @@ pub(super) const WORDS: &[Word] = &[
         name: "at",
         aliases: &[],
         category: "Time",
-        stack: "(v1..vn --)",
-        desc: "Set delta context for emit timing",
-        example: "0 0.5 at kick s . => emits at 0 and 0.5 of step",
+        stack: "(v1..vn -- )",
+        desc: "Looping block: re-executes body per delta. Close with . (audio), m. (MIDI), or done (no emit)",
+        example: "0 0.5 at kick snd 1 2 rand freq . | 0 0.5 at 60 note m. | 0 0.5 at !x done",
         compile: Simple,
         varargs: true,
     },

crates/forth/src/words/sound.rs

@@ -24,16 +24,6 @@ pub(super) const WORDS: &[Word] = &[
         compile: Simple,
         varargs: false,
     },
-    Word {
-        name: "arp",
-        aliases: &[],
-        category: "Sound",
-        stack: "(v1..vn -- arplist)",
-        desc: "Wrap stack values as arpeggio list for spreading across deltas",
-        example: "c4 e4 g4 b4 arp note => arpeggio",
-        compile: Simple,
-        varargs: true,
-    },
     Word {
         name: "clear",
         aliases: &[],

demos/01.cagire

@@ -7,7 +7,7 @@
           "steps": [
             {
               "i": 0,
-              "script": "0 7 .. at\n    c2 maj9 arp note\n    wide bigverb mysynth \n    2000 1000 0.4 0.8 rand expslide llpf\n    0.4 0.8 rand llpq\n    ."
+              "script": "0 7 .. at\n    mysynth [ c2 maj9 ] cycle note\n    wide bigverb\n    2000 1000 0.4 0.8 rand expslide llpf\n    0.4 0.8 rand llpq\n    ."
             },
             {
               "i": 8,

docs/tutorials/at.md

@@ -34,9 +34,9 @@ clear
 snare snd .               ;; 1 snare (deltas cleared)
 ```
 
-## Cross-product: at Without arp
+## Polyphonic at
 
-Without `arp`, deltas multiply with polyphonic voices. If you have 3 notes and 2 deltas, you get 6 emits -- every note at every delta:
+Deltas multiply with polyphonic voices. If you have 3 notes and 2 deltas, you get 6 emits — every note at every delta:
 
 ```forth
 0 0.5 at
@@ -45,27 +45,25 @@ c4 e4 g4 note 1.5 decay sine snd .
 
 6 emits: 3 notes x 2 deltas. A chord played twice per step.
 
-## 1:1 Pairing: at With arp
+## Arpeggios with at + cycle
 
-`arp` changes the behavior. Instead of cross-product, deltas and arp values pair up 1:1. Each delta gets one note from the arpeggio:
+Use `cycle` inside an `at` block to pick one note per subdivision:
 
 ```forth
 0 0.33 0.66 at
-c4 e4 g4 arp note 0.5 decay sine snd .
+sine snd [ c4 e4 g4 ] cycle note 0.5 decay .
 ```
 
-C4 at 0, E4 at 0.33, G4 at 0.66.
+C4 at 0, E4 at 0.33, G4 at 0.66. `cycle` advances per iteration of the at-loop.
 
-If the lists differ in length, the shorter one wraps around:
+If the list is shorter than the number of deltas, it wraps:
 
 ```forth
 0 0.25 0.5 0.75 at
-c4 e4 arp note 0.3 decay sine snd .
+sine snd [ c4 e4 ] cycle note 0.3 decay .
 ```
 
-C4, E4, C4, E4 — the shorter list wraps to fill 4 time points.
-
-This is THE key distinction. Without `arp`: every note at every time. With `arp`: one note per time slot.
+C4, E4, C4, E4 — wraps to fill 4 time points.
 
 ## Generating Deltas
 

docs/tutorials/generators.md

@@ -1,6 +1,6 @@
 # Generators & Sequences
 
-Sequences of values drive music: arpeggios, parameter sweeps, rhythmic patterns. Cagire has dedicated words for building sequences on the stack, transforming them, and collapsing them to single values.
+Sequences of values drive music: melodic patterns, parameter sweeps, rhythmic patterns. Cagire has dedicated words for building sequences on the stack, transforming them, and collapsing them to single values.
 
 ## Ranges
 
@@ -81,7 +81,7 @@ Four words reshape values already on the stack. All take n (the count of items t
 
 ```forth
 1 2 3 4 4 rev     ;; 4 3 2 1
-c4 e4 g4 3 rev    ;; g4 e4 c4 (descending arpeggio)
+c4 e4 g4 3 rev    ;; g4 e4 c4 (descending)
 ```
 
 `shuffle` randomizes order:

docs/tutorials/harmony.md

@@ -302,10 +302,10 @@ Combine with voicings for smoother voice leading:
 note 1.5 decay saw snd .
 ```
 
-Arpeggiate diatonic chords using `arp` (see the *Timing with at* tutorial for details on `arp`):
+Arpeggiate diatonic chords using `at` + `cycle` (see the *Timing with at* tutorial):
 
 ```forth
-0 major seventh arp note 0.5 decay sine snd .
+0 0.25 0.5 0.75 at sine snd [ 0 major seventh ] cycle note 0.5 decay .
 ```
 
 ## Frequency Conversion

tests/forth/midi.rs

@@ -253,19 +253,12 @@ fn test_midi_at_with_polyphony() {
 }
 
 #[test]
-fn test_midi_arp_notes() {
-    let outputs = expect_outputs("c4 e4 g4 arp note m.", 3);
-    assert!(outputs[0].contains("/note/60/"));
-    assert!(outputs[1].contains("/note/64/"));
-    assert!(outputs[2].contains("/note/67/"));
-}
-
-#[test]
-fn test_midi_arp_with_at() {
-    let outputs = expect_outputs("0 0.25 0.5 at c4 e4 g4 arp note m.", 3);
-    assert!(outputs[0].contains("/note/60/"));
-    assert!(outputs[1].contains("/note/64/"));
-    assert!(outputs[2].contains("/note/67/"));
+fn test_midi_at_loop_notes() {
+    // at-loop with m. closer: 3 iterations, each emits one MIDI note
+    let outputs = expect_outputs("0 0.25 0.5 at 60 note m.", 3);
+    for o in &outputs {
+        assert!(o.contains("/note/60/"));
+    }
 }
 
 #[test]

tests/forth/temporal.rs

@@ -171,7 +171,9 @@ fn at_three_deltas() {
 
 #[test]
 fn at_persists_across_emits() {
-    let outputs = expect_outputs(r#"0 0.5 at "kick" snd . "hat" snd ."#, 4);
+    // With at as a loop, each at...block is independent.
+    // Two separate at blocks each emit twice.
+    let outputs = expect_outputs(r#"0 0.5 at "kick" snd . 0 0.5 at "hat" snd ."#, 4);
     let sounds = get_sounds(&outputs);
     assert_eq!(sounds, vec!["kick", "kick", "hat", "hat"]);
 }
@@ -202,17 +204,10 @@ fn at_records_selected_spans() {
     let script = r#"0 0.5 0.75 at "kick" snd ."#;
     f.evaluate_with_trace(script, &default_ctx(), &mut trace).unwrap();
 
-    // Should have 6 selected spans: 3 for at deltas + 3 for sound (one per emit)
-    assert_eq!(trace.selected_spans.len(), 6, "expected 6 selected spans (3 at + 3 sound)");
-
-    // Verify at delta spans (even indices: 0, 2, 4)
-    assert_eq!(&script[trace.selected_spans[0].start as usize..trace.selected_spans[0].end as usize], "0");
-    assert_eq!(&script[trace.selected_spans[2].start as usize..trace.selected_spans[2].end as usize], "0.5");
-    assert_eq!(&script[trace.selected_spans[4].start as usize..trace.selected_spans[4].end as usize], "0.75");
+    // With at-loop, each iteration emits once: 3 sound spans total
+    assert_eq!(trace.selected_spans.len(), 3, "expected 3 selected spans (1 sound per iteration)");
 }
 
-// --- arp tests ---
-
 fn get_notes(outputs: &[String]) -> Vec<f64> {
     outputs
         .iter()
@@ -220,16 +215,13 @@ fn get_notes(outputs: &[String]) -> Vec<f64> {
         .collect()
 }
 
-fn get_gains(outputs: &[String]) -> Vec<f64> {
-    outputs
-        .iter()
-        .map(|o| parse_params(o).get("gain").copied().unwrap_or(f64::NAN))
-        .collect()
-}
-
 #[test]
-fn arp_auto_subdivide() {
-    let outputs = expect_outputs(r#"sine snd c4 e4 g4 b4 arp note ."#, 4);
+fn at_loop_with_cycle_notes() {
+    // at-loop + cycle replaces at + arp: cycle advances per subdivision
+    let ctx = ctx_with(|c| c.runs = 0);
+    let f = forth();
+    let outputs = f.evaluate(r#"0 0.25 0.5 0.75 at sine snd [ c4 e4 g4 b4 ] cycle note ."#, &ctx).unwrap();
+    assert_eq!(outputs.len(), 4);
     let notes = get_notes(&outputs);
     assert!(approx_eq(notes[0], 60.0));
     assert!(approx_eq(notes[1], 64.0));
@@ -245,104 +237,41 @@ fn arp_auto_subdivide() {
 }
 
 #[test]
-fn arp_with_explicit_at() {
-    let outputs = expect_outputs(r#"0 0.25 0.5 0.75 at sine snd c4 e4 g4 b4 arp note ."#, 4);
+fn at_loop_cycle_wraps() {
+    // cycle inside at-loop wraps when more deltas than items
+    let ctx = ctx_with(|c| c.runs = 0);
+    let f = forth();
+    let outputs = f.evaluate(r#"0 0.25 0.5 0.75 at sine snd [ c4 e4 ] cycle note ."#, &ctx).unwrap();
+    assert_eq!(outputs.len(), 4);
     let notes = get_notes(&outputs);
-    assert!(approx_eq(notes[0], 60.0));
-    assert!(approx_eq(notes[1], 64.0));
-    assert!(approx_eq(notes[2], 67.0));
-    assert!(approx_eq(notes[3], 71.0));
-    let deltas = get_deltas(&outputs);
-    let step_dur = 0.125;
-    let sr: f64 = 48000.0;
-    assert!(approx_eq(deltas[0], 0.0));
-    assert!(approx_eq(deltas[1], (0.25 * step_dur * sr).round()));
-    assert!(approx_eq(deltas[2], (0.5 * step_dur * sr).round()));
-    assert!(approx_eq(deltas[3], (0.75 * step_dur * sr).round()));
+    assert!(approx_eq(notes[0], 60.0)); // idx 0 % 2 = 0 -> c4
+    assert!(approx_eq(notes[1], 64.0)); // idx 1 % 2 = 1 -> e4
+    assert!(approx_eq(notes[2], 60.0)); // idx 2 % 2 = 0 -> c4
+    assert!(approx_eq(notes[3], 64.0)); // idx 3 % 2 = 1 -> e4
 }
 
 #[test]
-fn arp_single_note() {
-    let outputs = expect_outputs(r#"sine snd c4 arp note ."#, 1);
-    let notes = get_notes(&outputs);
-    assert!(approx_eq(notes[0], 60.0));
+fn at_loop_rand_different_per_subdivision() {
+    // rand inside at-loop produces different values per iteration
+    let f = forth();
+    let outputs = f.evaluate(r#"0 0.5 at sine snd 1 1000 rand freq ."#, &default_ctx()).unwrap();
+    assert_eq!(outputs.len(), 2);
+    let freqs: Vec<f64> = outputs.iter()
+        .map(|o| parse_params(o).get("freq").copied().unwrap_or(0.0))
+        .collect();
+    assert!(freqs[0] != freqs[1], "rand should produce different values: {} vs {}", freqs[0], freqs[1]);
 }
 
 #[test]
-fn arp_fewer_deltas_than_notes() {
-    let outputs = expect_outputs(r#"0 0.5 at sine snd c4 e4 g4 b4 arp note ."#, 4);
-    let notes = get_notes(&outputs);
-    assert!(approx_eq(notes[0], 60.0));
-    assert!(approx_eq(notes[1], 64.0));
-    assert!(approx_eq(notes[2], 67.0));
-    assert!(approx_eq(notes[3], 71.0));
-    let deltas = get_deltas(&outputs);
-    let step_dur = 0.125;
-    let sr: f64 = 48000.0;
-    assert!(approx_eq(deltas[0], 0.0));
-    assert!(approx_eq(deltas[1], (0.5 * step_dur * sr).round()));
-    assert!(approx_eq(deltas[2], 0.0));                            // wraps: 2 % 2 = 0
-    assert!(approx_eq(deltas[3], (0.5 * step_dur * sr).round()));  // wraps: 3 % 2 = 1
-}
-
-#[test]
-fn arp_fewer_notes_than_deltas() {
-    let outputs = expect_outputs(r#"0 0.25 0.5 0.75 at sine snd c4 e4 arp note ."#, 4);
-    let notes = get_notes(&outputs);
-    assert!(approx_eq(notes[0], 60.0));
-    assert!(approx_eq(notes[1], 64.0));
-    assert!(approx_eq(notes[2], 60.0)); // wraps
-    assert!(approx_eq(notes[3], 64.0)); // wraps
-}
-
-#[test]
-fn arp_multiple_params() {
-    let outputs = expect_outputs(r#"sine snd c4 e4 g4 arp note 0.5 0.7 0.9 arp gain ."#, 3);
-    let notes = get_notes(&outputs);
-    assert!(approx_eq(notes[0], 60.0));
-    assert!(approx_eq(notes[1], 64.0));
-    assert!(approx_eq(notes[2], 67.0));
-    let gains = get_gains(&outputs);
-    assert!(approx_eq(gains[0], 0.5));
-    assert!(approx_eq(gains[1], 0.7));
-    assert!(approx_eq(gains[2], 0.9));
-}
-
-#[test]
-fn arp_no_arp_unchanged() {
-    // Standard CycleList without arp → cross-product (backward compat)
+fn at_loop_poly_cycling() {
+    // CycleList inside at-loop: poly stacking within each iteration
     let outputs = expect_outputs(r#"0 0.5 at sine snd c4 e4 note ."#, 4);
     let notes = get_notes(&outputs);
-    // Cross-product: each note at each delta
-    assert!(approx_eq(notes[0], 60.0));
-    assert!(approx_eq(notes[1], 60.0));
-    assert!(approx_eq(notes[2], 64.0));
-    assert!(approx_eq(notes[3], 64.0));
-}
-
-#[test]
-fn arp_mixed_cycle_and_arp() {
-    // CycleList sound (2) + ArpList note (3) → 3 arp × 2 poly = 6 voices
-    // Each arp step plays both sine and saw simultaneously (poly stacking)
-    let outputs = expect_outputs(r#"sine saw snd c4 e4 g4 arp note ."#, 6);
-    let sounds = get_sounds(&outputs);
-    // Arp step 0: poly 0=sine, poly 1=saw
-    assert_eq!(sounds[0], "sine");
-    assert_eq!(sounds[1], "saw");
-    // Arp step 1: poly 0=sine, poly 1=saw
-    assert_eq!(sounds[2], "sine");
-    assert_eq!(sounds[3], "saw");
-    // Arp step 2: poly 0=sine, poly 1=saw
-    assert_eq!(sounds[4], "sine");
-    assert_eq!(sounds[5], "saw");
-    let notes = get_notes(&outputs);
-    // Both poly voices in each arp step share the same note
-    assert!(approx_eq(notes[0], 60.0));
-    assert!(approx_eq(notes[1], 60.0));
-    assert!(approx_eq(notes[2], 64.0));
-    assert!(approx_eq(notes[3], 64.0));
-    assert!(approx_eq(notes[4], 67.0));
-    assert!(approx_eq(notes[5], 67.0));
+    // Each iteration emits both poly voices (c4 and e4)
+    assert!(approx_eq(notes[0], 60.0));  // iter 0, poly 0
+    assert!(approx_eq(notes[1], 64.0));  // iter 0, poly 1
+    assert!(approx_eq(notes[2], 60.0));  // iter 1, poly 0
+    assert!(approx_eq(notes[3], 64.0));  // iter 1, poly 1
 }
 
 // --- every+ / except+ tests ---
@@ -400,3 +329,102 @@ fn every_offset_zero_is_same_as_every() {
         assert_eq!(a.len(), b.len(), "iter={}: every and every+ 0 should match", iter);
     }
 }
+
+// --- at-loop feature tests ---
+
+#[test]
+fn at_loop_choose_independent_per_subdivision() {
+    let f = forth();
+    let outputs = f.evaluate(r#"0 0.5 at sine snd [ 60 64 67 71 ] choose note ."#, &default_ctx()).unwrap();
+    assert_eq!(outputs.len(), 2);
+    // Both are valid notes from the set (just verify they're within range)
+    let notes = get_notes(&outputs);
+    for n in &notes {
+        assert!([60.0, 64.0, 67.0, 71.0].contains(n), "unexpected note {n}");
+    }
+}
+
+#[test]
+fn at_loop_multiple_blocks_independent() {
+    let outputs = expect_outputs(
+        r#"0 0.5 at "kick" snd . 0 0.25 0.5 at "hat" snd ."#,
+        5,
+    );
+    let sounds = get_sounds(&outputs);
+    assert_eq!(sounds[0], "kick");
+    assert_eq!(sounds[1], "kick");
+    assert_eq!(sounds[2], "hat");
+    assert_eq!(sounds[3], "hat");
+    assert_eq!(sounds[4], "hat");
+}
+
+#[test]
+fn at_loop_single_delta_one_iteration() {
+    let outputs = expect_outputs(r#"0.25 at "kick" snd ."#, 1);
+    let sounds = get_sounds(&outputs);
+    assert_eq!(sounds[0], "kick");
+    let deltas = get_deltas(&outputs);
+    let step_dur = 0.125;
+    let sr: f64 = 48000.0;
+    assert!(approx_eq(deltas[0], (0.25 * step_dur * sr).round()));
+}
+
+#[test]
+fn at_without_closer_falls_back_to_legacy() {
+    // When at has no matching closer (., m., done), falls back to Op::At
+    let f = forth();
+    let result = f.evaluate(r#"0 0.5 at "kick" snd"#, &default_ctx());
+    assert!(result.is_ok());
+}
+
+#[test]
+fn at_loop_cycle_advances_across_runs() {
+    // Across different runs values, cycle inside at-loop picks correctly
+    for base_runs in 0..3 {
+        let ctx = ctx_with(|c| c.runs = base_runs);
+        let f = forth();
+        let outputs = f.evaluate(
+            r#"0 0.5 at sine snd [ c4 e4 g4 ] cycle note ."#,
+            &ctx,
+        ).unwrap();
+        assert_eq!(outputs.len(), 2);
+        let notes = get_notes(&outputs);
+        // runs for iter i = base_runs * 2 + i
+        let expected_0 = [60.0, 64.0, 67.0][(base_runs * 2) % 3];
+        let expected_1 = [60.0, 64.0, 67.0][(base_runs * 2 + 1) % 3];
+        assert!(approx_eq(notes[0], expected_0), "runs={base_runs}: iter 0 expected {expected_0}, got {}", notes[0]);
+        assert!(approx_eq(notes[1], expected_1), "runs={base_runs}: iter 1 expected {expected_1}, got {}", notes[1]);
+    }
+}
+
+#[test]
+fn at_loop_midi_emit() {
+    let f = forth();
+    let outputs = f.evaluate("0 0.25 0.5 at 60 note m.", &default_ctx()).unwrap();
+    assert_eq!(outputs.len(), 3);
+    for o in &outputs {
+        assert!(o.contains("/midi/note/60/"));
+    }
+    // First should have no delta (or delta/0), others should have delta
+    assert!(outputs[1].contains("/delta/"));
+    assert!(outputs[2].contains("/delta/"));
+}
+
+#[test]
+fn at_loop_done_no_emit() {
+    let f = forth();
+    let outputs = f.evaluate("0 0.5 at [ 1 2 ] cycle drop done", &default_ctx()).unwrap();
+    assert!(outputs.is_empty());
+}
+
+#[test]
+fn at_loop_done_sets_variables() {
+    let f = forth();
+    let outputs = f
+        .evaluate("0 0.5 at [ 10 20 ] cycle !x done kick snd @x freq .", &default_ctx())
+        .unwrap();
+    assert_eq!(outputs.len(), 1);
+    // Last iteration wins: cycle(1) = 20
+    let params = parse_params(&outputs[0]);
+    assert!(approx_eq(*params.get("freq").unwrap(), 20.0));
+}