Offchain scaffolding.

offchain/src/gp/genetic_ops.rs

@@ -0,0 +1,10 @@
+use crate::compiler::ast::{Expr};
+
+pub fn crossover(a: &Expr, b: &Expr) -> (Expr, Expr) {
+    // stub
+    (a.clone(), b.clone())
+}
+
+pub fn mutate(expr: &mut Expr) {
+    // stub
+}

offchain/src/gp/mod.rs

@@ -0,0 +1,13 @@
+pub mod population;
+pub mod genetic_ops;
+// pub mod fitness;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_dummy() {
+        assert_eq!(2+2, 4);
+    }
+}

offchain/src/gp/population.rs

@@ -0,0 +1,9 @@
+#[derive(Debug, Clone)]
+pub struct Individual {
+    pub fitness: f64,
+    // your Expr or bytecode or both
+}
+
+pub struct Population {
+    pub individuals: Vec<Individual>,
+}