Wrote parser and added tests for it.

Refactored tests a little.

Cargo.lock

@@ -1,32 +0,0 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
-version = 4
-
-[[package]]
-name = "assert_approx_eq"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3c07dab4369547dbe5114677b33fbbf724971019f3818172d59a97a61c774ffd"
-
-[[package]]
-name = "autocfg"
-version = "1.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
-
-[[package]]
-name = "code"
-version = "0.1.0"
-dependencies = [
- "assert_approx_eq",
- "num-traits",
-]
-
-[[package]]
-name = "num-traits"
-version = "0.2.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
-dependencies = [
- "autocfg",
-]

Cargo.toml

@@ -5,4 +5,5 @@ edition = "2024"
 
 [dependencies]
 assert_approx_eq = "1.1.0"
+nom = "8.0.0"
 num-traits = "0.2"

src/main.rs

@@ -1,5 +1,7 @@
 use num_traits::Float;
 
+mod parser;
+
 /*
  * NOTES
  * - each alternative should appear only once in a tree. need to figure out a
@@ -7,22 +9,25 @@ use num_traits::Float;
  * - looks like this is like quite difficult to do through the type system
  */
 
-#[derive(PartialEq, Eq)]
-struct Alternative<T: Eq> {
+#[derive(PartialEq, Eq, Debug)]
+pub struct Alternative<T: Eq> {
   name: T
 }
 
-struct Edge<T: Eq, U: Float> {
+#[derive(PartialEq, Eq, Debug)]
+pub struct Edge<T: Eq, U: Float> {
   weight: U,
   destination: Tree<T, U>
 }
 
-enum Vertex<T: Eq, U: Float> {
+#[derive(PartialEq, Eq, Debug)]
+pub enum Vertex<T: Eq, U: Float> {
   NonTerminal(Box<Edge<T, U>>, Box<Edge<T, U>>),
   Terminal(Alternative<T>),
 }
 
-struct Tree<T: Eq, U: Float> {
+#[derive(PartialEq, Eq, Debug)]
+pub struct Tree<T: Eq, U: Float> {
   root: Vertex<T, U>
 }
 
@@ -84,11 +89,13 @@ mod tests {
   use super::*;
   use assert_approx_eq::assert_approx_eq;
 
-  // A test for the simplest symmetric case
-  #[test]
-  fn choice_probability_test_1() {
-    let a = Alternative {name: "A"};
-    let b = Alternative {name: "B"};
+  fn simple_symmetric_tree() -> Tree<String, f64> {
+    let a = Alternative {
+      name: "A".to_owned()
+    };
+    let b = Alternative {
+      name: "B".to_owned()
+    };
     let edge_a = Edge {
       weight: 1.0,
       destination: Tree {root: Vertex::Terminal(a)}
@@ -98,28 +105,38 @@ mod tests {
       destination: Tree {root: Vertex::Terminal(b)}
     };
     let root = Vertex::NonTerminal(Box::new(edge_a), Box::new(edge_b));
-    let tree = Tree {root: root};
-    assert_eq!(tree.choice_probability(&"A"), 0.5);
+    Tree {root: root}
   }
 
-  // A test for the simplest asymmetric case
-  #[test]
-  fn choice_probability_test_2() {
-    let a = Alternative {name: "A"};
-    let b = Alternative {name: "B"};
-    let edge_a = Edge {weight: 3.0, destination: Tree {root: Vertex::Terminal(a)}};
-    let edge_b = Edge {weight: 1.0, destination: Tree {root: Vertex::Terminal(b)}};
+  fn simple_asymmetric_tree() -> Tree<String, f64> {
+    let a = Alternative {
+      name: "A".to_owned()
+    };
+    let b = Alternative {
+      name: "B".to_owned()
+    };
+    let edge_a = Edge {
+      weight: 3.0,
+      destination: Tree {root: Vertex::Terminal(a)}
+    };
+    let edge_b = Edge {
+      weight: 1.0,
+      destination: Tree {root: Vertex::Terminal(b)}
+    };
     let root = Vertex::NonTerminal(Box::new(edge_a), Box::new(edge_b));
-    let tree = Tree {root: root};
-    assert_eq!(tree.choice_probability(&"A"), 0.75);
+    Tree {root: root}
   }
 
-  // A test for depth higher than 1
-  #[test]
-  fn choice_probability_test_3() {
-    let a = Alternative {name: "A"};
-    let b = Alternative {name: "B"};
-    let c = Alternative {name: "C"};
+  fn complex_tree() -> Tree<String, f64> {
+    let a = Alternative {
+      name: "A".to_owned()
+    };
+    let b = Alternative {
+      name: "B".to_owned()
+    };
+    let c = Alternative {
+      name: "C".to_owned()
+    };
     let edge_a = Edge {
       weight: 2.5,
       destination: Tree {root: Vertex::Terminal(a)}
@@ -139,10 +156,62 @@ mod tests {
       destination: Tree {root: Vertex::Terminal(c)}
     };
     let root = Vertex::NonTerminal(Box::new(edge_ab), Box::new(edge_c));
-    let tree = Tree {root: root};
+    Tree {root: root}
+  }
+
+
+  // A test for the simplest symmetric case
+  #[test]
+  fn choice_probability_test_1() {
+    assert_eq!(simple_symmetric_tree().choice_probability(&("A".to_owned())), 0.5);
+  }
+
+  // A test for the simplest asymmetric case
+  #[test]
+  fn choice_probability_test_2() {
+    assert_eq!(simple_asymmetric_tree().choice_probability(&("A".to_owned())), 0.75);
+  }
+
+  // A test for depth higher than 1
+  #[test]
+  fn choice_probability_test_3() {
     assert_approx_eq!(
-      tree.choice_probability(&"A"),
+      complex_tree().choice_probability(&("A".to_owned())),
       (2.5/(2.5+1.0))*((2.5+1.0+0.5)/(2.5+1.0+0.5+1.0))
     );
   }
+
+  // A test for parsing the simplest symmetric case
+  #[test]
+  fn parser_test_1() {
+    assert_eq!(
+      {
+        let (_, b) = parser::subtree("([1.0]A[1.0]B)").unwrap();
+        b
+      },
+      simple_symmetric_tree()
+    )
+  }
+
+  #[test]
+  fn parser_test_2() {
+    assert_eq!(
+      {
+        let (_, b) = parser::subtree("([3.0]A[1.0]B)").unwrap();
+        b
+      },
+      simple_asymmetric_tree()
+    )
+  }
+
+  #[test]
+  fn parser_test_3() {
+    assert_eq!(
+      {
+        let (_, b) = parser::subtree("([0.5]([2.5]A[1.0]B)[1.0]C)").unwrap();
+        b
+      },
+      complex_tree()
+    )
+  }
 }

src/parser.rs

@@ -0,0 +1,39 @@
+/*
+ * WHAT WE ARE PARSING:
+ * 
+ */
+
+use nom::{branch::alt, bytes::complete::take_while1, character::char, combinator::map, error::Error, number::complete::double, sequence::{delimited, pair}, AsChar, IResult, Parser};
+
+use crate::{Alternative, Edge, Tree, Vertex};
+
+fn weighted_edge(input: &str) -> IResult<&str, Edge<String, f64>> {
+  let weight = delimited(
+    char::<&str, Error<&str>>('['),
+    double,
+    char(']')
+  );
+  let alternative = map(
+    take_while1::<_, &str, Error<&str>>(AsChar::is_alpha),
+    |a| Tree::<String, f64> {
+      root: Vertex::Terminal(Alternative{name: a.to_string()})
+    }
+  );
+  map(
+    pair(weight, alt((alternative, subtree))),
+    |(a, b)| Edge{
+      weight: a,
+      destination: b
+    }
+  ).parse(input)
+}
+
+pub fn subtree(input: &str) -> IResult<&str, Tree<String, f64>> {
+  let inner = map(
+      pair(weighted_edge, weighted_edge),
+      |(a, b)| Tree{
+        root: Vertex::NonTerminal(Box::new(a), Box::new(b))
+      }
+    );
+  delimited(char('('), inner, char(')')).parse(input)
+}