feat: Adding serde as an optional dependency

Cargo.toml

@@ -10,6 +10,11 @@ publish = false
 anyhow = "1.0.75"
 pest = "2.7.5"
 pest_derive = "2.7.5"
+serde = { version = "1", features = ["derive"], optional = true }
 
 [dev-dependencies]
 divan = "0.1.2"
+
+[features]
+default = []
+serde = ["dep:serde"]

src/model.rs

@@ -8,6 +8,7 @@ use crate::{
 };
 
 #[derive(Debug, Default)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 /// A enum representing the bounds of a variable
 pub enum VariableType {
  /// Unbounded variable (-Infinity, +Infinity)
@@ -28,12 +29,14 @@ pub enum VariableType {
 }
 
 #[derive(Debug)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Objective {
  pub name: String,
  pub coefficients: Vec<Coefficient>,
 }
 
 #[derive(Debug)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Coefficient {
  pub var_name: String,
  pub coefficient: f64,
@@ -61,6 +64,7 @@ impl TryFrom<Pairs<'_, Rule>> for Coefficient {
 }
 
 #[derive(Debug)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Constraint {
  pub name: String,
  pub coefficients: Vec<Coefficient>,
@@ -69,13 +73,15 @@ pub struct Constraint {
 }
 
 #[derive(Debug, Default, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum Sense {
  #[default]
  Minimize,
  Maximize,
 }
 
 #[derive(Debug, Default)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct LPDefinition {
  pub problem_sense: Sense,
  pub variables: HashMap<String, VariableType>,