Trying to organize it all :$

planner/src/solver.rs

@@ -13,7 +13,7 @@ enum Assignment<'a, V> {
     Clear(String)
 }
 
-
+type Domains<'a, V> = HashMap<String, &'a Domain<V>>;
 /// The domain of values that can be assigned to variables
 #[derive(Clone)]
 pub struct Domain<V> {
@@ -51,13 +51,14 @@ impl<V: fmt::Debug> fmt::Debug for Domain<V> {
     }
 }
 
+
 pub type Constraint<'a,V> = fn(&Variables<'a,V>) -> bool;
 
 pub struct Problem<'a, V> {
     /// The initial assignements map
     variables: Variables<'a, V>,
     /// Each variable has its associated domain
-    domains: HashMap<String, &'a Domain<V>>,
+    domains: Domains<'a,V>,
     /// Set of constraints to validate
     constraints: Vec<Constraint<'a,V>>,
 }
@@ -141,11 +142,10 @@ impl<'a, V> ProblemBuilder<'a, V> {
             })
     }
 
-    pub fn add_variable(mut self,
-        name: String,
-        domain: &'a Domain<V>,
-        value: Option<&'a V>,
-    ) -> Self {
+    pub fn add_variable<S>(mut self, name: S, domain: &'a Domain<V>, value: Option<&'a V>) -> Self
+        where S: Into<String>
+    {
+        let name = name.into();
         self.0.variables.insert(name.clone(), value);
         self.0.domains.insert(name, domain);
         self