Add initial replicant crate

Cargo.toml

@@ -1,6 +1,7 @@
 [workspace]
 members = [
-  "editor"
+  "editor",
+  "replicant"
 ]
 
 [package]

replicant/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "replicant"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+glam = "0.21"
+termtree = "0.4"

replicant/src/lib.rs

@@ -0,0 +1,148 @@
+use std::fmt;
+use termtree;
+
+#[non_exhaustive]
+#[derive(Copy, Clone, Debug)]
+pub enum FieldOp {
+    Add,
+    Sub,
+    Mul,
+    Div,
+}
+
+impl fmt::Display for FieldOp {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let name = match self {
+            FieldOp::Add => "+",
+            FieldOp::Sub => "-",
+            FieldOp::Mul => "*",
+            FieldOp::Div => "/",
+        };
+
+        write!(f, "{}", name)
+    }
+}
+
+pub trait Field: fmt::Debug + Clone {
+    fn op(&self, other: Self, op: FieldOp) -> Self;
+}
+
+#[derive(Debug)]
+pub struct FieldNode<T: Field> {
+    field: T,
+    op: FieldOp,
+    children: Vec<FieldNode<T>>,
+}
+
+impl<T: Field> FieldNode<T> {
+    pub fn evaluate(&self) -> T {
+        let mut result = self.field.clone();
+
+        for child in self.children.iter() {
+            let child_result = child.evaluate();
+            result = result.op(child_result, child.op);
+        }
+
+        result
+    }
+
+    pub fn to_termtree(&self) -> termtree::Tree<String> {
+        let desc = format!("{} {:?} ({:?})", self.op, self.field, self.evaluate());
+        let mut tree = termtree::Tree::new(desc);
+
+        for child in self.children.iter() {
+            tree.push(child.to_termtree());
+        }
+
+        tree
+    }
+}
+
+impl<T: Field> fmt::Display for FieldNode<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.to_termtree())
+    }
+}
+
+impl Field for f32 {
+    fn op(&self, other: Self, op: FieldOp) -> Self {
+        match op {
+            FieldOp::Add => self + other,
+            FieldOp::Sub => self - other,
+            FieldOp::Mul => self * other,
+            FieldOp::Div => self / other,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_nodes() {
+        use FieldOp::*;
+
+        let nodes: FieldNode<f32> = FieldNode {
+            field: 10.0,
+            op: Add,
+            children: vec![
+                FieldNode {
+                    field: 4.0,
+                    op: Add,
+                    children: Vec::new(),
+                },
+                FieldNode {
+                    field: 2.0,
+                    op: Sub,
+                    children: vec![
+                        FieldNode {
+                            field: 0.0,
+                            op: Add,
+                            children: vec![
+                                FieldNode {
+                                    field: 0.6,
+                                    op: Add,
+                                    children: Vec::new(),
+                                },
+                                FieldNode {
+                                    field: 0.2,
+                                    op: Sub,
+                                    children: Vec::new(),
+                                },
+                            ],
+                        },
+                        FieldNode {
+                            field: 3.0,
+                            op: Div,
+                            children: Vec::new(),
+                        },
+                    ],
+                },
+                FieldNode {
+                    field: 7.0,
+                    op: Mul,
+                    children: vec![
+                        FieldNode {
+                            field: 0.75,
+                            op: Add,
+                            children: Vec::new(),
+                        },
+                        FieldNode {
+                            field: 0.5,
+                            op: Sub,
+                            children: Vec::new(),
+                        },
+                        FieldNode {
+                            field: 2.0,
+                            op: Div,
+                            children: Vec::new(),
+                        },
+                    ],
+                },
+            ],
+        };
+
+        println!("{}", nodes);
+    }
+}