Merge pull request #123 from flyingrobots/echo/F32Scalar

Echo/f32 scalar

Closes #114

Author: flyingrobots

crates/rmg-core/src/math/mod.rs

@@ -8,7 +8,7 @@ use std::f32::consts::TAU;
 mod mat4;
 mod prng;
 mod quat;
-mod scalar;
+pub mod scalar;
 mod vec3;
 
 #[doc(inline)]

crates/rmg-core/src/math/scalar.rs

@@ -82,3 +82,88 @@ pub trait Scalar:
     /// even) and ensure platform-stable results.
     fn to_f32(self) -> f32;
 }
+
+/// Deterministic f32 value
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub struct F32Scalar {
+    /// The wrapped f32 value
+    pub value: f32,
+}
+
+impl F32Scalar {
+    /// Nil value
+    pub const ZERO: Self = Self::new(0.0);
+
+    /// Identity value
+    pub const ONE: Self = Self::new(1.0);
+
+    /// Constructs a `F32Scalar` with the specified value `num`
+    pub const fn new(num: f32) -> Self {
+        Self { value: num }
+    }
+}
+
+impl Scalar for F32Scalar {
+    fn zero() -> Self {
+        Self::ZERO
+    }
+
+    fn one() -> Self {
+        Self::ONE
+    }
+
+    fn sin(self) -> Self {
+        Self::new(self.value.sin())
+    }
+
+    fn cos(self) -> Self {
+        Self::new(self.value.cos())
+    }
+
+    fn sin_cos(self) -> (Self, Self) {
+        (Self::new(self.value.sin()), Self::new(self.value.cos()))
+    }
+
+    fn from_f32(value: f32) -> Self {
+        Self::new(value)
+    }
+
+    fn to_f32(self) -> f32 {
+        self.value
+    }
+}
+
+impl Add for F32Scalar {
+    type Output = Self;
+    fn add(self, rhs: Self) -> Self {
+        Self::new(self.value + rhs.value)
+    }
+}
+
+impl Sub for F32Scalar {
+    type Output = Self;
+    fn sub(self, rhs: Self) -> Self {
+        Self::new(self.value - rhs.value)
+    }
+}
+
+impl Mul for F32Scalar {
+    type Output = Self;
+    fn mul(self, rhs: Self) -> Self {
+        Self::new(self.value * rhs.value)
+    }
+}
+
+impl Div for F32Scalar {
+    type Output = Self;
+    fn div(self, rhs: Self) -> Self {
+        Self::new(self.value / rhs.value)
+    }
+}
+
+impl Neg for F32Scalar {
+    type Output = Self;
+    fn neg(self) -> Self {
+        Self::new(-self.value)
+    }
+}

crates/rmg-core/tests/math_scalar_tests.rs

@@ -0,0 +1,25 @@
+#![allow(missing_docs)]
+use rmg_core::math::scalar::F32Scalar;
+use rmg_core::math::Scalar;
+
+#[test]
+fn test_f32_basics() {
+    // constants
+    let zero = F32Scalar::ZERO;
+    let one = F32Scalar::ONE;
+    assert_eq!(zero.value, 0.0);
+    assert_eq!(one.value, 1.0);
+
+    // basic math
+    let a = F32Scalar::new(5.0);
+    let b = F32Scalar::new(2.0);
+    assert_eq!((a + b).value, 7.0);
+    assert_eq!((a - b).value, 3.0);
+
+    assert_eq!((a * b).value, 10.0);
+    assert_eq!((a / b).value, 2.5);
+
+    let angle = F32Scalar::new(std::f32::consts::PI);
+    assert_eq!(angle.sin().value, angle.value.sin());
+    assert_eq!(angle.cos().value, angle.value.cos());
+}

docs/decision-log.md

@@ -4,6 +4,7 @@
 
 | Date | Context | Decision | Rationale | Consequence |
 | ---- | ------- | -------- | --------- | ----------- |
+| 2025-11-29 | `F32Scalar` | Add `rmg-core::math::scalar::F32Scalar` type | Now we have it. |
 | 2025-11-03 | Scalar foundation | Add `rmg-core::math::Scalar` trait (operator supertraits + sin/cos) | Arithmetic via `Add/Sub/Mul/Div/Neg` supertraits for ergonomic `+ - * /`; `sin/cos` methods declared; canonicalization/LUTs deferred | Unblocks F32Scalar and DFix64 implementations; math code can target a stable trait |
 | 2025-10-23 | Repo reset | Adopt pnpm + TS skeleton | Monorepo scaffolding for Echo | Phase 0 tasks established |
 | 2025-10-24 | Branch tree spec | Integrate roaring bitmaps and chunk epochs | Deterministic merges & diffs | Snapshot policy updated |

docs/echo-total.md

@@ -260,6 +260,10 @@ This is Codex’s working map for building Echo. Update it relentlessly—each s
 
 ## Today’s Intent
 
+> 2025-11-29 – Finish off `F32Scalar` implementation
+
+- Added `rmg-core::math::scalar::F32Scalar` type.
+
 > 2025-11-03 — Issue #115: Scalar trait scaffold
 
 - Added `rmg-core::math::scalar::Scalar` trait declaring deterministic scalar operations.
@@ -606,6 +610,7 @@ Remember: every entry here shrinks temporal drift between Codices. Leave breadcr
 
 | Date | Context | Decision | Rationale | Consequence |
 | ---- | ------- | -------- | --------- | ----------- |
+| 2025-11-29 | `F32Scalar` | Add `rmg-core::math::scalar::F32Scalar` type | Now we have it. |
 | 2025-11-03 | Scalar foundation | Add `rmg-core::math::Scalar` trait (operator supertraits + sin/cos) | Arithmetic via `Add/Sub/Mul/Div/Neg` supertraits for ergonomic `+ - * /`; `sin/cos` methods declared; canonicalization/LUTs deferred | Unblocks F32Scalar and DFix64 implementations; math code can target a stable trait |
 | 2025-10-23 | Repo reset | Adopt pnpm + TS skeleton | Monorepo scaffolding for Echo | Phase 0 tasks established |
 | 2025-10-24 | Branch tree spec | Integrate roaring bitmaps and chunk epochs | Deterministic merges & diffs | Snapshot policy updated |

docs/execution-plan.md

@@ -33,6 +33,10 @@ This is Codex’s working map for building Echo. Update it relentlessly—each s
 
 ## Today’s Intent
 
+> 2025-11-29 – Finish off `F32Scalar` implementation
+
+- Added `rmg-core::math::scalar::F32Scalar` type.
+
 > 2025-11-03 — Issue #115: Scalar trait scaffold
 
 - Added `rmg-core::math::scalar::Scalar` trait declaring deterministic scalar operations.