All about temporal semantics

src/main.rs

@@ -18,10 +18,7 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use clap::Parser;
-use crossterm::event::{
+use crossterm::event::{self, Event};
-    self, Event, KeyboardEnhancementFlags, PopKeyboardEnhancementFlags,
-    PushKeyboardEnhancementFlags,
-};
 use crossterm::terminal::{
     disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen,
 };
@@ -134,11 +131,6 @@ fn main() -> io::Result<()> {
 
     enable_raw_mode()?;
     io::stdout().execute(EnterAlternateScreen)?;
-    let _ = io::stdout().execute(PushKeyboardEnhancementFlags(
-        KeyboardEnhancementFlags::REPORT_EVENT_TYPES
-            | KeyboardEnhancementFlags::REPORT_ALL_KEYS_AS_ESCAPE_CODES,
-    ));
-
     let backend = CrosstermBackend::new(io::stdout());
     let mut terminal = Terminal::new(backend)?;
 
@@ -217,7 +209,6 @@ fn main() -> io::Result<()> {
 
     }
 
-    let _ = io::stdout().execute(PopKeyboardEnhancementFlags);
     disable_raw_mode()?;
     io::stdout().execute(LeaveAlternateScreen)?;
 

src/model/forth.rs

@@ -195,6 +195,7 @@ pub enum Op {
     ListEndPCycle,
     At,
     Window,
+    Scale,
     Pop,
     Subdivide,
     SetTempo,
@@ -205,6 +206,11 @@ pub enum Op {
     Unless,
     Adsr,
     Ad,
+    Stack,
+    For,
+    LocalCycleEnd,
+    Echo,
+    Necho,
 }
 
 pub enum WordCompile {
@@ -448,19 +454,26 @@ pub const WORDS: &[Word] = &[
         example: "\"kick\" s emit",
         compile: Simple,
     },
-    // Variables
     Word {
-        name: "get",
+        name: "@",
-        stack: "(name -- val)",
+        stack: "(--)",
-        desc: "Get variable value",
+        desc: "Alias for emit",
-        example: "\"x\" get",
+        example: "\"kick\" s 0.5 at @ pop",
+        compile: Alias("emit"),
+    },
+    // Variables (prefix syntax: @name to fetch, !name to store)
+    Word {
+        name: "@<var>",
+        stack: "( -- val)",
+        desc: "Fetch variable value",
+        example: "@freq => 440",
         compile: Simple,
     },
     Word {
-        name: "set",
+        name: "!<var>",
-        stack: "(val name --)",
+        stack: "(val --)",
-        desc: "Set variable value",
+        desc: "Store value in variable",
-        example: "42 \"x\" set",
+        example: "440 !freq",
         compile: Simple,
     },
     // Randomness
@@ -682,22 +695,22 @@ pub const WORDS: &[Word] = &[
     Word {
         name: "at",
         stack: "(pos --)",
-        desc: "Emit at position in window",
+        desc: "Position in time (push context)",
-        example: "0.5 at",
+        example: "\"kick\" s 0.5 at emit pop",
         compile: Simple,
     },
     Word {
-        name: "@",
+        name: "zoom",
-        stack: "(pos --)",
+        stack: "(start end --)",
-        desc: "Alias for at",
+        desc: "Zoom into time region",
-        example: "\"kick\" s 0.5 @",
+        example: "0.0 0.5 zoom",
-        compile: Alias("at"),
+        compile: Simple,
     },
     Word {
-        name: "window",
+        name: "scale!",
-        stack: "(start end --)",
+        stack: "(factor --)",
-        desc: "Create time window",
+        desc: "Scale time context duration",
-        example: "0.0 0.5 window",
+        example: "2 scale!",
         compile: Simple,
     },
     Word {
@@ -721,6 +734,41 @@ pub const WORDS: &[Word] = &[
         example: "4 div each",
         compile: Simple,
     },
+    Word {
+        name: "stack",
+        stack: "(n --)",
+        desc: "Create n subdivisions at same time",
+        example: "3 stack",
+        compile: Simple,
+    },
+    Word {
+        name: "echo",
+        stack: "(n --)",
+        desc: "Create n subdivisions with halving durations (stutter)",
+        example: "3 echo",
+        compile: Simple,
+    },
+    Word {
+        name: "necho",
+        stack: "(n --)",
+        desc: "Create n subdivisions with doubling durations (swell)",
+        example: "3 necho",
+        compile: Simple,
+    },
+    Word {
+        name: "for",
+        stack: "(quot --)",
+        desc: "Execute quotation for each subdivision",
+        example: "{ emit } 3 div for",
+        compile: Simple,
+    },
+    Word {
+        name: "|",
+        stack: "(-- marker)",
+        desc: "Start local cycle list",
+        example: "| 60 62 64 |",
+        compile: Simple,
+    },
     Word {
         name: "tempo!",
         stack: "(bpm --)",
@@ -1577,8 +1625,6 @@ fn simple_op(name: &str) -> Option<Op> {
         "not" => Op::Not,
         "sound" => Op::NewCmd,
         "emit" => Op::Emit,
-        "get" => Op::Get,
-        "set" => Op::Set,
         "rand" => Op::Rand,
         "rrand" => Op::Rrand,
         "seed" => Op::Seed,
@@ -1594,7 +1640,8 @@ fn simple_op(name: &str) -> Option<Op> {
         "?" => Op::When,
         "!?" => Op::Unless,
         "at" => Op::At,
-        "window" => Op::Window,
+        "zoom" => Op::Window,
+        "scale!" => Op::Scale,
         "pop" => Op::Pop,
         "div" => Op::Subdivide,
         "each" => Op::Each,
@@ -1605,6 +1652,10 @@ fn simple_op(name: &str) -> Option<Op> {
         ">>" => Op::ListEndPCycle,
         "adsr" => Op::Adsr,
         "ad" => Op::Ad,
+        "stack" => Op::Stack,
+        "for" => Op::For,
+        "echo" => Op::Echo,
+        "necho" => Op::Necho,
         _ => return None,
     })
 }
@@ -1629,6 +1680,31 @@ fn compile_word(name: &str, ops: &mut Vec<Op>) -> bool {
             return true;
         }
     }
+
+    // @varname - fetch variable
+    if let Some(var_name) = name.strip_prefix('@') {
+        if !var_name.is_empty() {
+            ops.push(Op::PushStr(var_name.to_string(), None));
+            ops.push(Op::Get);
+            return true;
+        }
+    }
+
+    // !varname - store into variable
+    if let Some(var_name) = name.strip_prefix('!') {
+        if !var_name.is_empty() {
+            ops.push(Op::PushStr(var_name.to_string(), None));
+            ops.push(Op::Set);
+            return true;
+        }
+    }
+
+    // Internal ops not exposed in WORDS
+    if let Some(op) = simple_op(name) {
+        ops.push(op);
+        return true;
+    }
+
     false
 }
 
@@ -1637,6 +1713,7 @@ struct TimeContext {
     start: f64,
     duration: f64,
     subdivisions: Option<Vec<(f64, f64)>>,
+    iteration_index: Option<usize>,
 }
 
 #[derive(Clone, Debug)]
@@ -1734,6 +1811,7 @@ fn tokenize(input: &str) -> Vec<Token> {
 fn compile(tokens: &[Token]) -> Result<Vec<Op>, String> {
     let mut ops = Vec::new();
     let mut i = 0;
+    let mut pipe_parity = false;
 
     while i < tokens.len() {
         match &tokens[i] {
@@ -1750,7 +1828,14 @@ fn compile(tokens: &[Token]) -> Result<Vec<Op>, String> {
             }
             Token::Word(w, _) => {
                 let word = w.as_str();
-                if word == "if" {
+                if word == "|" {
+                    if pipe_parity {
+                        ops.push(Op::LocalCycleEnd);
+                    } else {
+                        ops.push(Op::ListStart);
+                    }
+                    pipe_parity = !pipe_parity;
+                } else if word == "if" {
                     let (then_ops, else_ops, consumed) = compile_if(&tokens[i + 1..])?;
                     i += consumed;
                     if else_ops.is_empty() {
@@ -1897,6 +1982,7 @@ impl Forth {
             start: 0.0,
             duration: ctx.step_duration(),
             subdivisions: None,
+            iteration_index: None,
         }];
         let mut cmd = CmdRegister::default();
 
@@ -1910,16 +1996,6 @@ impl Forth {
             trace,
         )?;
 
-        if outputs.is_empty() {
-            if let Some((sound, params)) = cmd.take() {
-                let mut pairs = vec![("sound".into(), sound)];
-                pairs.extend(params);
-                pairs.push(("dur".into(), ctx.step_duration().to_string()));
-                pairs.push(("delaytime".into(), ctx.step_duration().to_string()));
-                outputs.push(format_cmd(&pairs));
-            }
-        }
-
         Ok(outputs)
     }
 
@@ -2078,14 +2154,13 @@ impl Forth {
                         pairs.push(("delta".into(), time_ctx.start.to_string()));
                     }
                     if !pairs.iter().any(|(k, _)| k == "dur") {
-                        pairs.push(("dur".into(), ctx.step_duration().to_string()));
+                        pairs.push(("dur".into(), time_ctx.duration.to_string()));
                     }
-                    let stepdur = ctx.step_duration();
                     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 * stepdur).to_string();
+                        pairs[idx].1 = (ratio * time_ctx.duration).to_string();
                     } else {
-                        pairs.push(("delaytime".into(), stepdur.to_string()));
+                        pairs.push(("delaytime".into(), time_ctx.duration.to_string()));
                     }
                     outputs.push(format_cmd(&pairs));
                 }
@@ -2206,7 +2281,9 @@ impl Forth {
                     if val < prob {
                         match quot {
                             Value::Quotation(quot_ops) => {
-                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, None)?;
+                                let mut trace_opt = trace_cell.borrow_mut().take();
+                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, trace_opt.as_deref_mut())?;
+                                *trace_cell.borrow_mut() = trace_opt;
                             }
                             _ => return Err("expected quotation".into()),
                         }
@@ -2220,7 +2297,9 @@ impl Forth {
                     if val < pct / 100.0 {
                         match quot {
                             Value::Quotation(quot_ops) => {
-                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, None)?;
+                                let mut trace_opt = trace_cell.borrow_mut().take();
+                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, trace_opt.as_deref_mut())?;
+                                *trace_cell.borrow_mut() = trace_opt;
                             }
                             _ => return Err("expected quotation".into()),
                         }
@@ -2251,7 +2330,9 @@ impl Forth {
                     if cond.is_truthy() {
                         match quot {
                             Value::Quotation(quot_ops) => {
-                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, None)?;
+                                let mut trace_opt = trace_cell.borrow_mut().take();
+                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, trace_opt.as_deref_mut())?;
+                                *trace_cell.borrow_mut() = trace_opt;
                             }
                             _ => return Err("expected quotation".into()),
                         }
@@ -2264,7 +2345,9 @@ impl Forth {
                     if !cond.is_truthy() {
                         match quot {
                             Value::Quotation(quot_ops) => {
-                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, None)?;
+                                let mut trace_opt = trace_cell.borrow_mut().take();
+                                self.execute_ops(&quot_ops, ctx, stack, outputs, time_stack, cmd, trace_opt.as_deref_mut())?;
+                                *trace_cell.borrow_mut() = trace_opt;
                             }
                             _ => return Err("expected quotation".into()),
                         }
@@ -2285,25 +2368,14 @@ impl Forth {
 
                 Op::At => {
                     let pos = stack.pop().ok_or("stack underflow")?.as_float()?;
-                    let (sound, mut params) = cmd.take().ok_or("no sound set")?;
+                    let parent = time_stack.last().ok_or("time stack underflow")?;
-                    let mut pairs = vec![("sound".into(), sound)];
+                    let new_start = parent.start + parent.duration * pos;
-                    pairs.append(&mut params);
+                    time_stack.push(TimeContext {
-                    let time_ctx = time_stack.last().ok_or("time stack underflow")?;
+                        start: new_start,
-                    let absolute_time = time_ctx.start + time_ctx.duration * pos;
+                        duration: parent.duration * (1.0 - pos),
-                    if absolute_time > 0.0 {
+                        subdivisions: None,
-                        pairs.push(("delta".into(), absolute_time.to_string()));
+                        iteration_index: parent.iteration_index,
-                    }
+                    });
-                    if !pairs.iter().any(|(k, _)| k == "dur") {
-                        pairs.push(("dur".into(), ctx.step_duration().to_string()));
-                    }
-                    let stepdur = ctx.step_duration();
-                    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 * stepdur).to_string();
-                    } else {
-                        pairs.push(("delaytime".into(), stepdur.to_string()));
-                    }
-                    outputs.push(format_cmd(&pairs));
                 }
 
                 Op::Window => {
@@ -2316,6 +2388,18 @@ impl Forth {
                         start: new_start,
                         duration: new_duration,
                         subdivisions: None,
+                        iteration_index: parent.iteration_index,
+                    });
+                }
+
+                Op::Scale => {
+                    let factor = stack.pop().ok_or("stack underflow")?.as_float()?;
+                    let parent = time_stack.last().ok_or("time stack underflow")?;
+                    time_stack.push(TimeContext {
+                        start: parent.start,
+                        duration: parent.duration * factor,
+                        subdivisions: None,
+                        iteration_index: parent.iteration_index,
                     });
                 }
 
@@ -2347,21 +2431,20 @@ impl Forth {
                         .subdivisions
                         .as_ref()
                         .ok_or("each requires subdivide first")?;
-                    for (sub_start, _sub_dur) in subs {
+                    for (sub_start, sub_dur) in subs {
                         let mut pairs = vec![("sound".into(), sound.clone())];
                         pairs.extend(params.iter().cloned());
                         if *sub_start > 0.0 {
                             pairs.push(("delta".into(), sub_start.to_string()));
                         }
                         if !pairs.iter().any(|(k, _)| k == "dur") {
-                            pairs.push(("dur".into(), ctx.step_duration().to_string()));
+                            pairs.push(("dur".into(), sub_dur.to_string()));
                         }
-                        let stepdur = ctx.step_duration();
                         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 * stepdur).to_string();
+                            pairs[idx].1 = (ratio * sub_dur).to_string();
                         } else {
-                            pairs.push(("delaytime".into(), stepdur.to_string()));
+                            pairs.push(("delaytime".into(), sub_dur.to_string()));
                         }
                         outputs.push(format_cmd(&pairs));
                     }
@@ -2459,6 +2542,121 @@ impl Forth {
                     cmd.set_param("decay".into(), d.to_param_string());
                     cmd.set_param("sustain".into(), "0".into());
                 }
+
+                Op::Stack => {
+                    let n = stack.pop().ok_or("stack underflow")?.as_int()? as usize;
+                    if n == 0 {
+                        return Err("stack count must be > 0".into());
+                    }
+                    let time_ctx = time_stack.last_mut().ok_or("time stack underflow")?;
+                    let sub_duration = time_ctx.duration / n as f64;
+                    let mut subs = Vec::with_capacity(n);
+                    for _ in 0..n {
+                        subs.push((time_ctx.start, sub_duration));
+                    }
+                    time_ctx.subdivisions = Some(subs);
+                }
+
+                Op::Echo => {
+                    let n = stack.pop().ok_or("stack underflow")?.as_int()? as usize;
+                    if n == 0 {
+                        return Err("echo count must be > 0".into());
+                    }
+                    let time_ctx = time_stack.last_mut().ok_or("time stack underflow")?;
+                    // Geometric series: d1 * (2 - 2^(1-n)) = total
+                    let d1 = time_ctx.duration / (2.0 - 2.0_f64.powi(1 - n as i32));
+                    let mut subs = Vec::with_capacity(n);
+                    for i in 0..n {
+                        let dur = d1 / 2.0_f64.powi(i as i32);
+                        let start = if i == 0 {
+                            time_ctx.start
+                        } else {
+                            time_ctx.start + d1 * (2.0 - 2.0_f64.powi(1 - i as i32))
+                        };
+                        subs.push((start, dur));
+                    }
+                    time_ctx.subdivisions = Some(subs);
+                }
+
+                Op::Necho => {
+                    let n = stack.pop().ok_or("stack underflow")?.as_int()? as usize;
+                    if n == 0 {
+                        return Err("necho count must be > 0".into());
+                    }
+                    let time_ctx = time_stack.last_mut().ok_or("time stack underflow")?;
+                    // Reverse geometric: d1 + 2*d1 + 4*d1 + ... = d1 * (2^n - 1) = total
+                    let d1 = time_ctx.duration / (2.0_f64.powi(n as i32) - 1.0);
+                    let mut subs = Vec::with_capacity(n);
+                    for i in 0..n {
+                        let dur = d1 * 2.0_f64.powi(i as i32);
+                        let start = if i == 0 {
+                            time_ctx.start
+                        } else {
+                            // Sum of previous durations: d1 * (2^i - 1)
+                            time_ctx.start + d1 * (2.0_f64.powi(i as i32) - 1.0)
+                        };
+                        subs.push((start, dur));
+                    }
+                    time_ctx.subdivisions = Some(subs);
+                }
+
+                Op::For => {
+                    let quot = stack.pop().ok_or("stack underflow")?;
+                    let time_ctx = time_stack.last().ok_or("time stack underflow")?;
+                    let subs = time_ctx
+                        .subdivisions
+                        .clone()
+                        .ok_or("for requires subdivide first")?;
+
+                    match quot {
+                        Value::Quotation(quot_ops) => {
+                            for (i, (sub_start, sub_dur)) in subs.iter().enumerate() {
+                                time_stack.push(TimeContext {
+                                    start: *sub_start,
+                                    duration: *sub_dur,
+                                    subdivisions: None,
+                                    iteration_index: Some(i),
+                                });
+                                let mut trace_opt = trace_cell.borrow_mut().take();
+                                self.execute_ops(
+                                    &quot_ops,
+                                    ctx,
+                                    stack,
+                                    outputs,
+                                    time_stack,
+                                    cmd,
+                                    trace_opt.as_deref_mut(),
+                                )?;
+                                *trace_cell.borrow_mut() = trace_opt;
+                                time_stack.pop();
+                            }
+                        }
+                        _ => return Err("expected quotation".into()),
+                    }
+                }
+
+                Op::LocalCycleEnd => {
+                    let mut values = Vec::new();
+                    while let Some(v) = stack.pop() {
+                        if v.is_marker() {
+                            break;
+                        }
+                        values.push(v);
+                    }
+                    if values.is_empty() {
+                        return Err("empty local cycle list".into());
+                    }
+                    values.reverse();
+                    let time_ctx = time_stack.last().ok_or("time stack underflow")?;
+                    let idx = time_ctx.iteration_index.unwrap_or(0) % values.len();
+                    let selected = values[idx].clone();
+                    if let Some(span) = selected.span() {
+                        if let Some(trace) = trace_cell.borrow_mut().as_mut() {
+                            trace.selected_spans.push(span);
+                        }
+                    }
+                    stack.push(selected);
+                }
             }
             pc += 1;
         }

tests/forth.rs

@@ -33,3 +33,6 @@ mod variables;
 
 #[path = "forth/quotations.rs"]
 mod quotations;
+
+#[path = "forth/iteration.rs"]
+mod iteration;

tests/forth/errors.rs

@@ -20,16 +20,6 @@ fn string_not_number() {
     expect_error(r#""hello" neg"#, "expected number");
 }
 
-#[test]
-fn get_expects_string() {
-    expect_error("42 get", "expected string");
-}
-
-#[test]
-fn set_expects_string() {
-    expect_error("1 2 set", "expected string");
-}
-
 #[test]
 fn comment_ignored() {
     expect_int("1 (this is a comment) 2 +", 3);
@@ -54,7 +44,7 @@ fn float_literal() {
 
 #[test]
 fn string_with_spaces() {
-    let f = run(r#""hello world" "x" set "x" get"#);
+    let f = run(r#""hello world" !x @x"#);
     match stack_top(&f) {
         cagire::model::forth::Value::Str(s, _) => assert_eq!(s, "hello world"),
         other => panic!("expected string, got {:?}", other),
@@ -63,7 +53,6 @@ fn string_with_spaces() {
 
 #[test]
 fn list_count() {
-    // [ 1 2 3 ] => stack: 1 2 3 3 (items + count on top)
     let f = run("[ 1 2 3 ]");
     assert_eq!(stack_int(&f), 3);
 }
@@ -75,9 +64,6 @@ fn list_empty() {
 
 #[test]
 fn list_preserves_values() {
-    // [ 10 20 ] => stack: 10 20 2
-    // drop => 10 20
-    // + => 30
     expect_int("[ 10 20 ] drop +", 30);
 }
 
@@ -97,10 +83,10 @@ fn conditional_based_on_step() {
 fn accumulator() {
     let f = forth();
     let ctx = default_ctx();
-    f.evaluate(r#"0 "acc" set"#, &ctx).unwrap();
+    f.evaluate(r#"0 !acc"#, &ctx).unwrap();
     for _ in 0..5 {
         f.clear_stack();
-        f.evaluate(r#""acc" get 1 + dup "acc" set"#, &ctx).unwrap();
+        f.evaluate(r#"@acc 1 + dup !acc"#, &ctx).unwrap();
     }
     assert_eq!(stack_int(&f), 5);
 }

tests/forth/iteration.rs

@@ -0,0 +1,256 @@
+use super::harness::*;
+use std::collections::HashMap;
+
+fn parse_params(output: &str) -> HashMap<String, f64> {
+    let mut params = HashMap::new();
+    let parts: Vec<&str> = output.trim_start_matches('/').split('/').collect();
+    let mut i = 0;
+    while i + 1 < parts.len() {
+        if let Ok(v) = parts[i + 1].parse::<f64>() {
+            params.insert(parts[i].to_string(), v);
+        }
+        i += 2;
+    }
+    params
+}
+
+fn get_deltas(outputs: &[String]) -> Vec<f64> {
+    outputs
+        .iter()
+        .map(|o| parse_params(o).get("delta").copied().unwrap_or(0.0))
+        .collect()
+}
+
+fn get_durs(outputs: &[String]) -> Vec<f64> {
+    outputs
+        .iter()
+        .map(|o| parse_params(o).get("dur").copied().unwrap_or(0.0))
+        .collect()
+}
+
+fn get_notes(outputs: &[String]) -> Vec<f64> {
+    outputs
+        .iter()
+        .map(|o| parse_params(o).get("note").copied().unwrap_or(0.0))
+        .collect()
+}
+
+fn get_sounds(outputs: &[String]) -> Vec<String> {
+    outputs
+        .iter()
+        .map(|o| {
+            let parts: Vec<&str> = o.trim_start_matches('/').split('/').collect();
+            for i in (0..parts.len()).step_by(2) {
+                if parts[i] == "sound" && i + 1 < parts.len() {
+                    return parts[i + 1].to_string();
+                }
+            }
+            String::new()
+        })
+        .collect()
+}
+
+const EPSILON: f64 = 1e-9;
+
+fn approx_eq(a: f64, b: f64) -> bool {
+    (a - b).abs() < EPSILON
+}
+
+#[test]
+fn stack_creates_subdivisions_at_same_time() {
+    let outputs = expect_outputs(r#""kick" s 3 stack each"#, 3);
+    let deltas = get_deltas(&outputs);
+    assert!(approx_eq(deltas[0], 0.0));
+    assert!(approx_eq(deltas[1], 0.0));
+    assert!(approx_eq(deltas[2], 0.0));
+}
+
+#[test]
+fn stack_vs_div_timing() {
+    let stack_outputs = expect_outputs(r#""kick" s 3 stack each"#, 3);
+    let div_outputs = expect_outputs(r#""kick" s 3 div each"#, 3);
+
+    let stack_deltas = get_deltas(&stack_outputs);
+    let div_deltas = get_deltas(&div_outputs);
+
+    for d in stack_deltas {
+        assert!(approx_eq(d, 0.0), "stack should have all delta=0");
+    }
+
+    assert!(approx_eq(div_deltas[0], 0.0));
+    assert!(!approx_eq(div_deltas[1], 0.0), "div should spread in time");
+    assert!(!approx_eq(div_deltas[2], 0.0), "div should spread in time");
+}
+
+#[test]
+fn for_with_div_arpeggio() {
+    let outputs = expect_outputs(r#"{ "kick" s emit } 3 div for"#, 3);
+    let deltas = get_deltas(&outputs);
+
+    assert!(approx_eq(deltas[0], 0.0));
+    assert!(!approx_eq(deltas[1], 0.0));
+    assert!(!approx_eq(deltas[2], 0.0));
+}
+
+#[test]
+fn for_with_stack_chord() {
+    let outputs = expect_outputs(r#"{ "kick" s emit } 3 stack for"#, 3);
+    let deltas = get_deltas(&outputs);
+
+    for d in deltas {
+        assert!(approx_eq(d, 0.0), "stack for should have all delta=0");
+    }
+}
+
+#[test]
+fn local_cycle_with_for() {
+    let outputs = expect_outputs(r#"{ | 60 62 64 | note "sine" s emit } 3 div for"#, 3);
+    let notes = get_notes(&outputs);
+
+    assert!(approx_eq(notes[0], 60.0));
+    assert!(approx_eq(notes[1], 62.0));
+    assert!(approx_eq(notes[2], 64.0));
+}
+
+#[test]
+fn local_cycle_wraps_around() {
+    let outputs = expect_outputs(r#"{ | 60 62 | note "sine" s emit } 4 div for"#, 4);
+    let notes = get_notes(&outputs);
+
+    assert!(approx_eq(notes[0], 60.0));
+    assert!(approx_eq(notes[1], 62.0));
+    assert!(approx_eq(notes[2], 60.0));
+    assert!(approx_eq(notes[3], 62.0));
+}
+
+#[test]
+fn multiple_local_cycles() {
+    let outputs =
+        expect_outputs(r#"{ | "bd" "sn" | s | 60 64 | note emit } 2 stack for"#, 2);
+    let sounds = get_sounds(&outputs);
+    let notes = get_notes(&outputs);
+
+    assert_eq!(sounds[0], "bd");
+    assert_eq!(sounds[1], "sn");
+    assert!(approx_eq(notes[0], 60.0));
+    assert!(approx_eq(notes[1], 64.0));
+}
+
+#[test]
+fn local_cycle_outside_for_defaults_to_first() {
+    expect_int("| 60 62 64 |", 60);
+}
+
+#[test]
+fn polymetric_cycles() {
+    let outputs = expect_outputs(
+        r#"{ | 0 1 | n | "a" "b" "c" | s emit } 6 div for"#,
+        6,
+    );
+    let sounds = get_sounds(&outputs);
+
+    assert_eq!(sounds[0], "a");
+    assert_eq!(sounds[1], "b");
+    assert_eq!(sounds[2], "c");
+    assert_eq!(sounds[3], "a");
+    assert_eq!(sounds[4], "b");
+    assert_eq!(sounds[5], "c");
+}
+
+#[test]
+fn stack_error_zero_count() {
+    expect_error(r#""kick" s 0 stack each"#, "stack count must be > 0");
+}
+
+#[test]
+fn for_requires_subdivide() {
+    expect_error(r#"{ "kick" s emit } for"#, "for requires subdivide first");
+}
+
+#[test]
+fn for_requires_quotation() {
+    expect_error(r#"42 3 div for"#, "expected quotation");
+}
+
+#[test]
+fn empty_local_cycle() {
+    expect_error("| |", "empty local cycle list");
+}
+
+// Echo tests - stutter effect with halving durations
+
+#[test]
+fn echo_creates_decaying_subdivisions() {
+    // stepdur = 0.125, echo 3
+    // d1 + d1/2 + d1/4 = d1 * 1.75 = 0.125
+    // d1 = 0.125 / 1.75 = 0.0714285714...
+    let outputs = expect_outputs(r#""kick" s 3 echo each"#, 3);
+    let durs = get_durs(&outputs);
+    let deltas = get_deltas(&outputs);
+
+    let d1 = 0.125 / 1.75;
+    let d2 = d1 / 2.0;
+    let d3 = d1 / 4.0;
+
+    assert!(approx_eq(durs[0], d1), "first dur should be {}, got {}", d1, durs[0]);
+    assert!(approx_eq(durs[1], d2), "second dur should be {}, got {}", d2, durs[1]);
+    assert!(approx_eq(durs[2], d3), "third dur should be {}, got {}", d3, durs[2]);
+
+    assert!(approx_eq(deltas[0], 0.0), "first delta should be 0");
+    assert!(approx_eq(deltas[1], d1), "second delta should be {}, got {}", d1, deltas[1]);
+    assert!(approx_eq(deltas[2], d1 + d2), "third delta should be {}, got {}", d1 + d2, deltas[2]);
+}
+
+#[test]
+fn echo_with_for() {
+    let outputs = expect_outputs(r#"{ "kick" s emit } 3 echo for"#, 3);
+    let durs = get_durs(&outputs);
+
+    // Each subsequent duration should be half the previous
+    assert!(approx_eq(durs[1], durs[0] / 2.0), "second should be half of first");
+    assert!(approx_eq(durs[2], durs[1] / 2.0), "third should be half of second");
+}
+
+#[test]
+fn echo_error_zero_count() {
+    expect_error(r#""kick" s 0 echo each"#, "echo count must be > 0");
+}
+
+// Necho tests - reverse echo (durations grow)
+
+#[test]
+fn necho_creates_growing_subdivisions() {
+    // stepdur = 0.125, necho 3
+    // d1 + 2*d1 + 4*d1 = d1 * 7 = 0.125
+    // d1 = 0.125 / 7
+    let outputs = expect_outputs(r#""kick" s 3 necho each"#, 3);
+    let durs = get_durs(&outputs);
+    let deltas = get_deltas(&outputs);
+
+    let d1 = 0.125 / 7.0;
+    let d2 = d1 * 2.0;
+    let d3 = d1 * 4.0;
+
+    assert!(approx_eq(durs[0], d1), "first dur should be {}, got {}", d1, durs[0]);
+    assert!(approx_eq(durs[1], d2), "second dur should be {}, got {}", d2, durs[1]);
+    assert!(approx_eq(durs[2], d3), "third dur should be {}, got {}", d3, durs[2]);
+
+    assert!(approx_eq(deltas[0], 0.0), "first delta should be 0");
+    assert!(approx_eq(deltas[1], d1), "second delta should be {}, got {}", d1, deltas[1]);
+    assert!(approx_eq(deltas[2], d1 + d2), "third delta should be {}, got {}", d1 + d2, deltas[2]);
+}
+
+#[test]
+fn necho_with_for() {
+    let outputs = expect_outputs(r#"{ "kick" s emit } 3 necho for"#, 3);
+    let durs = get_durs(&outputs);
+
+    // Each subsequent duration should be double the previous
+    assert!(approx_eq(durs[1], durs[0] * 2.0), "second should be double first");
+    assert!(approx_eq(durs[2], durs[1] * 2.0), "third should be double second");
+}
+
+#[test]
+fn necho_error_zero_count() {
+    expect_error(r#""kick" s 0 necho each"#, "necho count must be > 0");
+}

tests/forth/quotations.rs

@@ -83,8 +83,8 @@ fn quotation_skips_emit() {
     let outputs = f
         .evaluate(r#""kick" s { emit } 0 ?"#, &default_ctx())
         .unwrap();
-    // Should have 1 output from implicit emit at end (since cmd is set but not emitted)
+    // No output since emit was skipped and no implicit emit
-    assert_eq!(outputs.len(), 1);
+    assert_eq!(outputs.len(), 0);
 }
 
 #[test]

tests/forth/sound.rs

@@ -37,13 +37,6 @@ fn emit_no_sound() {
     expect_error("emit", "no sound set");
 }
 
-#[test]
-fn implicit_emit() {
-    let outputs = expect_outputs(r#""kick" s 440 freq"#, 1);
-    assert!(outputs[0].contains("sound/kick"));
-    assert!(outputs[0].contains("freq/440"));
-}
-
 #[test]
 fn multiple_emits() {
     let outputs = expect_outputs(r#""kick" s emit "snare" s emit"#, 2);
@@ -57,9 +50,9 @@ fn subdivide_each() {
 }
 
 #[test]
-fn window_pop() {
+fn zoom_pop() {
     let outputs = expect_outputs(
-        r#"0.0 0.5 window "kick" s emit pop 0.5 1.0 window "snare" s emit"#,
+        r#"0.0 0.5 zoom "kick" s emit pop 0.5 1.0 zoom "snare" s emit"#,
         2,
     );
     assert!(outputs[0].contains("sound/kick"));

tests/forth/temporal.rs

@@ -47,8 +47,8 @@ fn emit_no_delta() {
 
 #[test]
 fn at_half() {
-    // at 0.5 in root window (0..0.125) => delta = 0.5 * 0.125 = 0.0625
+    // at 0.5 in root zoom (0..0.125) => delta = 0.5 * 0.125 = 0.0625
-    let outputs = expect_outputs(r#""kick" s 0.5 at"#, 1);
+    let outputs = expect_outputs(r#""kick" s 0.5 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
     assert!(
         approx_eq(deltas[0], 0.0625),
@@ -59,7 +59,7 @@ fn at_half() {
 
 #[test]
 fn at_quarter() {
-    let outputs = expect_outputs(r#""kick" s 0.25 at"#, 1);
+    let outputs = expect_outputs(r#""kick" s 0.25 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
     assert!(
         approx_eq(deltas[0], 0.03125),
@@ -70,7 +70,7 @@ fn at_quarter() {
 
 #[test]
 fn at_zero() {
-    let outputs = expect_outputs(r#""kick" s 0.0 at"#, 1);
+    let outputs = expect_outputs(r#""kick" s 0.0 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
     assert!(approx_eq(deltas[0], 0.0), "at 0.0 should be delta 0");
 }
@@ -117,83 +117,83 @@ fn div_3_each() {
 }
 
 #[test]
-fn window_full() {
+fn zoom_full() {
-    // window 0.0 1.0 is the full step, same as root
+    // zoom 0.0 1.0 is the full step, same as root
-    let outputs = expect_outputs(r#"0.0 1.0 window "kick" s 0.5 at"#, 1);
+    let outputs = expect_outputs(r#"0.0 1.0 zoom "kick" s 0.5 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
-    assert!(approx_eq(deltas[0], 0.0625), "full window at 0.5 = 0.0625");
+    assert!(approx_eq(deltas[0], 0.0625), "full zoom at 0.5 = 0.0625");
 }
 
 #[test]
-fn window_first_half() {
+fn zoom_first_half() {
-    // window 0.0 0.5 restricts to first half (0..0.0625)
+    // zoom 0.0 0.5 restricts to first half (0..0.0625)
     // at 0.5 within that = 0.25 of full step = 0.03125
-    let outputs = expect_outputs(r#"0.0 0.5 window "kick" s 0.5 at"#, 1);
+    let outputs = expect_outputs(r#"0.0 0.5 zoom "kick" s 0.5 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
     assert!(
         approx_eq(deltas[0], 0.03125),
-        "first-half window at 0.5 = 0.03125, got {}",
+        "first-half zoom at 0.5 = 0.03125, got {}",
         deltas[0]
     );
 }
 
 #[test]
-fn window_second_half() {
+fn zoom_second_half() {
-    // window 0.5 1.0 restricts to second half (0.0625..0.125)
+    // zoom 0.5 1.0 restricts to second half (0.0625..0.125)
     // at 0.0 within that = start of second half = 0.0625
-    let outputs = expect_outputs(r#"0.5 1.0 window "kick" s 0.0 at"#, 1);
+    let outputs = expect_outputs(r#"0.5 1.0 zoom "kick" s 0.0 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
     assert!(
         approx_eq(deltas[0], 0.0625),
-        "second-half window at 0.0 = 0.0625, got {}",
+        "second-half zoom at 0.0 = 0.0625, got {}",
         deltas[0]
     );
 }
 
 #[test]
-fn window_second_half_middle() {
+fn zoom_second_half_middle() {
-    // window 0.5 1.0, at 0.5 within that = 0.75 of full step = 0.09375
+    // zoom 0.5 1.0, at 0.5 within that = 0.75 of full step = 0.09375
-    let outputs = expect_outputs(r#"0.5 1.0 window "kick" s 0.5 at"#, 1);
+    let outputs = expect_outputs(r#"0.5 1.0 zoom "kick" s 0.5 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
     assert!(approx_eq(deltas[0], 0.09375), "got {}", deltas[0]);
 }
 
 #[test]
-fn nested_windows() {
+fn nested_zooms() {
-    // window 0.0 0.5, then window 0.5 1.0 within that
+    // zoom 0.0 0.5, then zoom 0.5 1.0 within that
     // outer: 0..0.0625, inner: 0.5..1.0 of that = 0.03125..0.0625
     // at 0.0 in inner = 0.03125
-    let outputs = expect_outputs(r#"0.0 0.5 window 0.5 1.0 window "kick" s 0.0 at"#, 1);
+    let outputs = expect_outputs(r#"0.0 0.5 zoom 0.5 1.0 zoom "kick" s 0.0 at emit pop"#, 1);
     let deltas = get_deltas(&outputs);
     assert!(
         approx_eq(deltas[0], 0.03125),
-        "nested window at 0.0 = 0.03125, got {}",
+        "nested zoom at 0.0 = 0.03125, got {}",
         deltas[0]
     );
 }
 
 #[test]
-fn window_pop_sequence() {
+fn zoom_pop_sequence() {
-    // First in window 0.0 0.5 at 0.0 -> delta 0
+    // First in zoom 0.0 0.5 at 0.0 -> delta 0
-    // Pop, then in window 0.5 1.0 at 0.0 -> delta 0.0625
+    // Pop at context and zoom, then in zoom 0.5 1.0 at 0.0 -> delta 0.0625
     let outputs = expect_outputs(
-        r#"0.0 0.5 window "kick" s 0.0 at pop 0.5 1.0 window "snare" s 0.0 at"#,
+        r#"0.0 0.5 zoom "kick" s 0.0 at emit pop pop 0.5 1.0 zoom "snare" s 0.0 at emit pop"#,
         2,
     );
     let deltas = get_deltas(&outputs);
-    assert!(approx_eq(deltas[0], 0.0), "first window start");
+    assert!(approx_eq(deltas[0], 0.0), "first zoom start");
     assert!(
         approx_eq(deltas[1], 0.0625),
-        "second window start, got {}",
+        "second zoom start, got {}",
         deltas[1]
     );
 }
 
 #[test]
-fn div_in_window() {
+fn div_in_zoom() {
-    // window 0.0 0.5 (duration 0.0625), then div 2 each
+    // zoom 0.0 0.5 (duration 0.0625), then div 2 each
     // subdivisions at 0 and 0.03125
-    let outputs = expect_outputs(r#"0.0 0.5 window "kick" s 2 div each"#, 2);
+    let outputs = expect_outputs(r#"0.0 0.5 zoom "kick" s 2 div each"#, 2);
     let deltas = get_deltas(&outputs);
     assert!(approx_eq(deltas[0], 0.0));
     assert!(approx_eq(deltas[1], 0.03125), "got {}", deltas[1]);

tests/forth/variables.rs

@@ -1,39 +1,44 @@
 use super::harness::*;
 
 #[test]
-fn set_get() {
+fn fetch_store() {
-    expect_int(r#"42 "x" set "x" get"#, 42);
+    expect_int(r#"42 !x @x"#, 42);
 }
 
 #[test]
-fn get_nonexistent() {
+fn fetch_nonexistent() {
-    expect_int(r#""novar" get"#, 0);
+    expect_int(r#"@novar"#, 0);
 }
 
 #[test]
 fn persistence_across_evals() {
     let f = forth();
     let ctx = default_ctx();
-    f.evaluate(r#"10 "counter" set"#, &ctx).unwrap();
+    f.evaluate(r#"10 !counter"#, &ctx).unwrap();
     f.clear_stack();
-    f.evaluate(r#""counter" get 1 +"#, &ctx).unwrap();
+    f.evaluate(r#"@counter 1 +"#, &ctx).unwrap();
     assert_eq!(stack_int(&f), 11);
 }
 
 #[test]
 fn overwrite() {
-    expect_int(r#"1 "x" set 99 "x" set "x" get"#, 99);
+    expect_int(r#"1 !x 99 !x @x"#, 99);
 }
 
 #[test]
 fn multiple_vars() {
-    let f = run(r#"10 "a" set 20 "b" set "a" get "b" get +"#);
+    let f = run(r#"10 !a 20 !b @a @b +"#);
     assert_eq!(stack_int(&f), 30);
 }
 
 #[test]
 fn float_var() {
-    let f = run(r#"3.14 "pi" set "pi" get"#);
+    let f = run(r#"3.14 !pi @pi"#);
     let val = stack_float(&f);
     assert!((val - 3.14).abs() < 1e-9);
 }
+
+#[test]
+fn increment_pattern() {
+    expect_int(r#"0 !n @n 1 + !n @n 1 + !n @n"#, 2);
+}