feat(codegen): enforce extraction of repeated expressions

.agents/skills/ptf-extract/SKILL.md

@@ -26,8 +26,11 @@ input error.
    blockers and set affected functions to `blocked`; otherwise set reviewed,
    complete functions to `ready-for-implementation`.
 4. Run `cargo run --manifest-path codegen/Cargo.toml -- validate` and fix
-   validation errors before finishing. Validation never justifies inferred
-   science.
+   validation errors before finishing. When a nontrivial formula expression is
+   repeated within one implementation, declare it once as an earlier local
+   implementation variable and reference that variable; retain the published
+   numeric lexemes and do not assign extra scientific semantics. Validation
+   never justifies inferred science.
 
 ## Output
 

.agents/skills/ptf-generate/SKILL.md

@@ -25,8 +25,12 @@ status when input validation fails; report the blocking input error.
    generated structures and classes; `$defs` keys only resolve local references.
    Do not infer missing science.
 3. Validate, generate both retained targets, and run the required verification
-   gates. A generator capability gap is a blocker, never an invitation to
-   hand-write that computational target.
+   gates. Before validation, extract each repeated nontrivial formula
+   expression within a function into one earlier local implementation variable
+   and reference it thereafter; retain published numeric lexemes and do not
+   invent scientific semantics for the calculation intermediate. A generator
+   capability gap is a blocker, never an invitation to hand-write that
+   computational target.
 4. After every required check passes, change the selected source functions from
    `ready-for-implementation` to `implemented`, then revalidate, regenerate,
    and prove the second generation pass is idempotent.

codegen/src/formula.rs

@@ -45,13 +45,13 @@ pub(crate) enum ExprKind {
     Grouped(Box<Expr>),
 }
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 pub(crate) enum UnaryOp {
     Plus,
     Minus,
 }
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 pub(crate) enum BinaryOp {
     Add,
     Subtract,

codegen/src/model.rs

@@ -355,9 +355,16 @@ pub(crate) struct RawVariable {
 #[derive(Clone, Debug)]
 pub(crate) struct RawExpression {
     pub(crate) implementation_path: String,
+    pub(crate) source_location: SourceLocation,
     pub(crate) expression: crate::formula::Expr,
 }
 
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub(crate) struct SourceLocation {
+    pub(crate) line: usize,
+    pub(crate) column: usize,
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;