Try to optimize

tests/forth/generator.rs

@@ -0,0 +1,104 @@
+use super::harness::*;
+use cagire::forth::Value;
+
+fn int(n: i64) -> Value {
+    Value::Int(n, None)
+}
+
+#[test]
+fn range_ascending() {
+    expect_stack("1 4 ..", &[int(1), int(2), int(3), int(4)]);
+}
+
+#[test]
+fn range_descending() {
+    expect_stack("4 1 ..", &[int(4), int(3), int(2), int(1)]);
+}
+
+#[test]
+fn range_single() {
+    expect_stack("3 3 ..", &[int(3)]);
+}
+
+#[test]
+fn range_negative() {
+    expect_stack("-2 1 ..", &[int(-2), int(-1), int(0), int(1)]);
+}
+
+#[test]
+fn range_underflow() {
+    expect_error("1 ..", "stack underflow");
+    expect_error("..", "stack underflow");
+}
+
+#[test]
+fn gen_basic() {
+    expect_stack("{ 42 } 3 gen", &[int(42), int(42), int(42)]);
+}
+
+#[test]
+fn gen_with_computation() {
+    // Each iteration: dup current value, add 1, result is new value
+    // 0 → dup(0,0) 1+(0,1) → pop 1, stack [0]
+    // 0 → dup(0,0) 1+(0,1) → pop 1, stack [0]
+    // So we get [0, 1, 1, 1] - the 0 stays, we collect three 1s
+    expect_stack("0 { dup 1 + } 3 gen", &[int(0), int(1), int(1), int(1)]);
+}
+
+#[test]
+fn gen_chained() {
+    // Start with 1, each iteration: dup, multiply by 2
+    // 1 → dup(1,1) 2*(1,2) → pop 2, stack [1]
+    // 1 → dup(1,1) 2*(1,2) → pop 2, stack [1]
+    expect_stack("1 { dup 2 * } 3 gen", &[int(1), int(2), int(2), int(2)]);
+}
+
+#[test]
+fn gen_zero() {
+    expect_stack("{ 1 } 0 gen", &[]);
+}
+
+#[test]
+fn gen_underflow() {
+    expect_error("3 gen", "stack underflow");
+}
+
+#[test]
+fn gen_not_a_number() {
+    expect_error("{ 1 } gen", "expected number");
+}
+
+#[test]
+fn gen_negative() {
+    expect_error("{ 1 } -1 gen", "gen count must be >= 0");
+}
+
+#[test]
+fn gen_empty_quot_error() {
+    expect_error("{ } 3 gen", "quotation must produce");
+}
+
+#[test]
+fn geom_growing() {
+    expect_stack("1 2 4 geom..", &[int(1), int(2), int(4), int(8)]);
+}
+
+#[test]
+fn geom_shrinking() {
+    expect_stack("8 0.5 4 geom..", &[int(8), int(4), int(2), int(1)]);
+}
+
+#[test]
+fn geom_single() {
+    expect_stack("5 2 1 geom..", &[int(5)]);
+}
+
+#[test]
+fn geom_zero_count() {
+    expect_stack("1 2 0 geom..", &[]);
+}
+
+#[test]
+fn geom_underflow() {
+    expect_error("1 2 geom..", "stack underflow");
+}