some more thinking...

cookbook/src/lib.rs

@@ -57,6 +57,7 @@ pub mod ingredients {
     use super::{SqliteConnection, schema};
     use super::diesel::prelude::*;
 
+    /// A wrapper of [`IngredientList`] with DB connection capacity.
     pub struct IngredientListManager<'a>(&'a SqliteConnection, IngredientList);
 
     impl<'a> IngredientListManager<'a> {
@@ -98,12 +99,9 @@ pub mod ingredients {
     fn find(conn: &SqliteConnection, name: &str) -> Option<Ingredient> {
         use self::schema::ingredients::dsl::*;
 
-        match ingredients.filter(alias.like(name))
-            .first(conn)
-        {
-            Ok(ingdt) => Some(ingdt),
-            Err(_) => None,
-        }
+        ingredients.filter(alias.like(name))
+                   .first(conn)
+                   .ok()
     }
 
     fn create(conn: &SqliteConnection, name: &str) -> Result<i32,String> {

cookbook/src/models.rs

@@ -144,6 +144,12 @@ pub struct Recipe {
     pub preparation: String,
 }
 
+impl PartialEq for Recipe {
+    fn eq(&self, other: &Recipe) -> bool {
+        self.id == other.id
+    }
+}
+
 #[derive(Insertable, Debug)]
 #[table_name="recipes"]
 pub struct NewRecipe<'a> {

planner/src/constraint.rs

@@ -0,0 +1,135 @@
+//! Constraints building
+//!
+//! # Ideas
+//!
+//! Each constraints will be updated on every assignment,
+//! thus their status is always inspectable.
+//! A constraint applies to a set of variables, identified
+//! by a key of type `K`.
+//! A constraint owns references to actual values assigned,
+//! used to perform checks.
+//!
+//!
+//! The problem is to clarify the way Constraints operate.
+//! Do they compute their status from some data on demand ?
+//! Do they keep their status updated by watching the Variables
+//! they act on ?
+//! Worse, do they have superpowers ?
+//! Could they filter on a variable domain, according to some other variable
+//! state ? This would mean that constraints won't judge a result, but guide
+//! the solving process to avoid erroring paths, like a constraint-driven
+//! solving. This would be powerfull but maybe far too complex...
+//!
+//! On the other hand, we can implement a simple Observer pattern, with strong
+//! coupling to [`Problem`](crate::solver::Problem).
+//! Because of this, we can safely play with private fields of Problem, and in
+//! return, provide a public api to build specific constraints.
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum Status {
+    Validated,// Solution is valid
+    Unknown,  // Constraint cannot resolve yet (unbound variables)
+    Violated, // Solution is invalid
+}
+
+use std::collections::HashMap;
+
+// *Like this
+enum ValueChecker {
+    AllDifferent,
+    AllSame,
+}
+
+pub struct Constraint<'c, V, K> {
+    status: Status,
+    variables: HashMap<&'c K, Option<&'c V>>,
+    // TODO: add a ValueChecker Trait object,
+    // or just a simple Enum.*
+    // to provide the check_status procedure, given
+    // a vector to variables values.
+}
+
+impl<'c, V, K> Constraint<'c, V, K>
+    where K: Eq + std::hash::Hash,
+          V: PartialEq,
+{
+
+    pub fn new(vars: Vec<&'c K>) -> Self {
+        let len = vars.len();
+        Self {
+            status: Status::Unknown,
+            variables: vars.into_iter()
+                           .zip(vec![None; len])
+                           .collect(),
+        }
+    }
+
+    pub fn status(&self) -> &Status {
+        &self.status
+    }
+
+    fn check_status(vars: Vec<&Option<&V>>) -> Status {
+        /// LEts do an hacky NotEqualConstraint
+        let vars_len = vars.len();
+        let set_vars: Vec<&Option<&V>> = vars.into_iter().filter(|v| v.is_some()).collect();
+        let is_complete = vars_len == set_vars.len();
+        for (idx, value) in set_vars.iter().enumerate() {
+            let violated = set_vars.iter()
+                .enumerate()
+                .filter(|(i,_)| *i != idx)
+                .fold(false, |res, (_,v)| {
+                    res || v == value
+                });
+            if violated { return Status::Violated; }
+        }
+        match is_complete {
+            true => Status::Validated,
+            false => Status::Unknown,
+        }
+    }
+
+    fn update_status(&mut self) {
+        self.status = Self::check_status(self.variables.values().collect());
+    }
+
+    pub fn update(&mut self, key: &K, new_value: Option<&'c V>) {
+        if let Some(value) = self.variables.get_mut(key) {
+            // Actually update values
+            dbg!(*value = new_value);
+            self.update_status();
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_all_different_problem() {
+        use crate::solver::{Domain, Problem};
+        use super::Constraint;
+
+        let domain = Domain::new(vec![1, 2, 3]);
+        let problem = Problem::build()
+            .add_variable("Left", domain.all(), None)
+            .add_variable("Right", domain.all(), None)
+            .add_constraint(Constraint::new(vec![&"Left", &"Right"]))
+            .finish();
+
+        let solutions = vec![
+            (("Left", Some(&1)), ("Right", Some(&2))),
+            (("Left", Some(&1)), ("Right", Some(&3))),
+            (("Left", Some(&2)), ("Right", Some(&1))),
+            (("Left", Some(&2)), ("Right", Some(&3))),
+            (("Left", Some(&3)), ("Right", Some(&1))),
+            (("Left", Some(&3)), ("Right", Some(&2))),
+        ];
+        let results = problem.solve_all();
+        println!("{:#?}", results);
+        assert!(results.len() == solutions.len());
+        results.into_iter().for_each(|res| {
+            let res = (("Left", *res.get("Left").unwrap()),
+                       ("Right", *res.get("Right").unwrap())) ;
+            assert!(solutions.contains(&res));
+        });
+    }
+}

planner/src/lib.rs

@@ -3,7 +3,7 @@ use cookbook::recipes::Recipe;
 
 pub mod solver;
 pub mod template;
-
+pub mod constraint;
 
 pub use solver::{Domain, DomainValues};
 /// We mainly use Recipe as the domain value type

planner/src/rules.rs

@@ -1,16 +1,56 @@
 //! Rules used by the `planner`
 //! A rule is a constraint on valid solutions, but also provides insights
 //! and eventually inferences to optimize the solving process.
+//!
+//! * Basic repartition
+//!    * All different meals
+//!    * Map recipes categories to each meals
+//!    * (Eating a dish over two days (leftovers))
+//! * Nutritional values
+//!    * Per day : according to user profile (man: 2000kcal, woman: 1800kcal)
+//!    * Per meal : some meals should have higher nutrional values than others
+//!
+//! * Ingredients
+//!    * Per week : should use most of a limited set of ingredients (excluding
+//!                 condiments, ...)
+//!    * To consume : must use a small set of ingredients (leftovers)
+//!
+//!
+//! Price
+//! - Per week : should restrict ingredients cost to a given amount
 
-// Nutritional values
-// - Per day : according to user profile (man: 2000kcal, woman: 1800kcal)
-// - Per meal : some meals should have higher nutrional values than others
+enum Status {
+    Ok,
+    Violated,
+}
 
-// Ingredients
-// - Per week : should use most of a limited set of ingredients (excluding
-// condiments, ...)
-// - To consume : must use a small set of ingredients (leftovers)
-//
+trait Rule {
+    type Key;
+    type Value;
 
-// Price
-// - Per week : should restrict ingredients cost to a given amount
+    fn status(&self, state: (Vec<&Self::Key>, Vec<&Self::Value>));
+    fn update(&self, idx: usize, value: Option<Self::Value>) -> Option<Filter>;
+};
+
+struct AllDifferentMeals;
+
+impl Rule for AllDifferentMeals {
+    type State = Vec<Recipe>;
+
+    fn status(&self, _: Self::State) -> Status {
+        Status::Ok // Always enforced by update rule
+    }
+
+    fn update(&self, _: Self::State) -> Option<Filter> {
+        // Returns a filter excluding this value from domain.
+        // so that it is impossible to select the same meal twice.
+        None
+    }
+}
+struct FilterRecipeByMeals; // Essentially work on domain
+
+struct NutritionalByDayAverageReq;
+struct NutritionalByMealAverageValues;
+
+struct IngredientsInFridge;
+struct IngredientsMustUse;

planner/src/solver.rs

@@ -6,11 +6,16 @@ use std::hash::Hash;
 use std::clone::Clone;
 use std::collections::HashMap;
 
-/// An assignments map of variables
-type Variables<'a, V> = Vec<Option<&'a V>>;
+use crate::constraint::{Status, Constraint};
+
 /// A solution returned by [`Solver`]
 pub type Solution<'a, V, K> = HashMap<K, Option<&'a V>>;
 
+
+/// An assignments map of variables
+type Variables<'a, V> = Vec<Option<&'a V>>;
+
+/// Orders used by solver to update variables
 enum Assignment<'a, V> {
     Update(usize, &'a V),
     Clear(usize)
@@ -100,8 +105,48 @@ impl<V: fmt::Debug> fmt::Debug for Domain<V> {
     }
 }
 
+/// Or we can have a much more complex version of Domain.
+/// We want to retrieve a filtered domain for each variable.
+/// Filters will be static (filter by category,...) or dynamic
+/// (inserted by rules updates).
+///
+/// For every variable, we can retrieve its filtered values (values,
+/// filtered by all globals, filtered by one local).
+/// Plus, set a dynamic filter that will apply to all other variables.
+/// Of course, it also affects this variable, but considering that dynamic
+/// filters are cleared and repopulated on every assign, this side-effect
+/// can never occur.
+struct SDomain<V, Filter> {
+    values: Vec<V>,
+    global_filters: Vec<Filter>, // Globals are dynamic Filters
+    local_filters: Vec<Filter>, // Locals are static Filters
+}
 
-pub type Constraint<'a,V> = fn(&Variables<'a,V>) -> bool;
+impl<V, F> SDomain<V, F> {
+    fn new(values: Vec<V>) -> Self {
+        Self {
+            values,
+            global_filters: Vec::new(),
+            local_filters: Vec::new(),
+        }
+    }
+
+    /// Returns the current domain values for a variable by index
+    fn get(&self, idx: usize) -> DomainValues<V> {
+        self.values
+            .iter()
+            .collect()
+    }
+
+    /// Adds a dynamic filter to globals, identified by its setter's id
+    /// /!\ Previously set filters are overriden, hence dynamic
+    fn set_global(&mut self, setter: usize, filter: F) {
+        self.global_filters[setter] = filter;
+    }
+}
+
+
+//pub type Constraint<'a,V> = fn(&Variables<'a,V>) -> bool;
 
 
 /// Could be more efficient to just use fixed array of options as variables,
@@ -109,23 +154,23 @@ pub type Constraint<'a,V> = fn(&Variables<'a,V>) -> bool;
 /// Domains could be a similar array of DomainValues.
 /// It makes sense with an array where indexing is O(1)
 
-pub struct Problem<'a, V, K> {
+pub struct Problem<'p, V, K> {
     keys: Vec<K>,
-    /// The initial assignements map
-    variables: Variables<'a, V>,
+    /// The initial assignements
+    variables: Variables<'p, V>,
     /// Each variable has its associated domain
-    domains: Vec<DomainValues<'a,V>>,
+    domains: Vec<DomainValues<'p,V>>,
     /// Set of constraints to validate
-    constraints: Vec<Constraint<'a,V>>,
+    constraints: Vec<Constraint<'p,V,K>>,
 }
 
-impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
+impl<'p, V: PartialEq, K: Eq + Hash + Clone> Problem<'p, V, K> {
 
-    pub fn build() -> ProblemBuilder<'a,V, K> {
+    pub fn build() -> ProblemBuilder<'p,V, K> {
         ProblemBuilder::new()
     }
 
-    pub fn from_template() -> Problem<'a, V, K> {
+    pub fn from_template() -> Problem<'p, V, K> {
         let builder = Self::build();
 
         builder.finish()
@@ -133,19 +178,20 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
 
     /// Returns all possible Updates for next assignements, prepended with
     /// a Clear to ensure the variable is unset before when leaving the branch.
-    fn _push_updates(&self) -> Option<Vec<Assignment<'a,V>>> {
-        // TODO: should be able to inject a choosing strategy
-        if let Some(key) = self._next_assign() {
+    fn _push_updates(&self) -> Option<Vec<Assignment<'p,V>>> {
+        if let Some(idx) = self._next_assign() {
+            // TODO: Domain will filter possible values for us
+            // let values = self.domain.get(idx);
             let domain_values = self.domains
-                                    .get(key)
+                                    .get(idx)
                                     .expect("No domain for variable !");
+            // TODO: handle case of empty domain.values
             assert!(!domain_values.is_empty());
             // Push a clear assignment first, just before going up the stack.
-            let mut updates = vec![Assignment::Clear(key.clone())];
-            // TODO: should be able to filter domain values (inference, pertinence)
+            let mut updates = vec![Assignment::Clear(idx.clone())];
             domain_values.iter().for_each(|value| {
                 updates.push(
-                    Assignment::Update(key, *value)
+                    Assignment::Update(idx, *value)
                 );
             });
             Some(updates)
@@ -155,6 +201,7 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
     }
 
     fn _next_assign(&self) -> Option<usize> {
+        // TODO: should be able to inject a choosing strategy
         self.variables.iter()
             .enumerate()
             .find_map(|(idx, val)| {
@@ -165,15 +212,41 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
 
     /// Checks that the current assignments doesn't violate any constraint
     fn _is_valid(&self) -> bool {
-        for validator in self.constraints.iter() {
-            if validator(&self.variables) == false { return false; }
+        for status in self.constraints.iter().map(|c| c.status()) {
+            if status == &Status::Violated { return false; }
         }
         return true;
     }
 
-    fn _solve(&mut self, limit: Option<usize>) -> Vec<Solution<'a, V, K>> {
+    fn _get_key(&self, idx: usize) -> &K {
+        &self.keys[idx]
+    }
+
+    fn _get_solution(&self) -> Solution<'p, V, K> {
+        // Returns the current state wrapped in a Solution type.
+        self.keys.iter().cloned()
+            .zip(self.variables.iter().cloned())
+            .collect()
+    }
+
+    /// Assigns a new value to the given index, then calls update
+    /// on every constraints.
+    fn _assign(&mut self, idx: usize, value: Option<&'p V>) {
+        self.variables[idx] = value;
+        let var_key = &self.keys[idx];
+        // TODO: manage dynamic filters on Domain
+        // let filters: Filter::Chain = self.constraints.iter_mut().map([...]).collect();
+        // self.domain.set_global(idx, filters);
+        self.constraints.iter_mut()
+                        .for_each(|c| {
+                            c.update(&var_key, value);
+                        });
+
+    }
+
+    fn _solve(&mut self, limit: Option<usize>) -> Vec<Solution<'p, V, K>> {
         let mut solutions: Vec<Solution<V, K>> = vec![];
-        let mut stack: Vec<Assignment<'a, V>> = vec![];
+        let mut stack: Vec<Assignment<'p, V>> = vec![];
         if let Some(mut init_updates) = self._push_updates() {
             stack.append(&mut init_updates);
         } else {
@@ -195,25 +268,19 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
             match node.unwrap() {
                 Assignment::Update(idx, val) => {
                     // Assign the variable and open new branches, if any.
-                    self.variables[idx] = Some(val);
-                    // TODO: handle case of empty domain.values
+                    self._assign(idx, Some(val));
                     if let Some(mut nodes) = self._push_updates() {
                         stack.append(&mut nodes);
                     } else {
                         // Assignements are completed
                         if self._is_valid() {
-                            solutions.push(
-                                // Builds Solution
-                                self.keys.iter().cloned()
-                                    .zip(self.variables.iter().cloned())
-                                    .collect()
-                            );
+                            solutions.push(self._get_solution());
                         };
                     };
                 },
                 Assignment::Clear(idx) => {
                     // We are closing this branch, unset the variable
-                    self.variables[idx] = None;
+                    self._assign(idx, None);
                 },
             };
         };
@@ -221,25 +288,25 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
 
     }
     /// Returns all complete solutions, after visiting all possible outcomes using a stack (DFS).
-    pub fn solve_all(&mut self) -> Vec<Solution<'a,V,K>>
-        where V: Clone + fmt::Debug,
-              K: Clone + fmt::Debug,
+    pub fn solve_all(mut self) -> Vec<Solution<'p,V,K>>
+        where V: fmt::Debug,
+              K: fmt::Debug,
     {
         self._solve(None) // No limit
     }
 
-    pub fn solve_one(&mut self) -> Option<Solution<'a,V,K>>
-        where V: Clone + fmt::Debug,
-              K: Clone + fmt::Debug,
+    pub fn solve_one(mut self) -> Option<Solution<'p,V,K>>
+        where V: fmt::Debug,
+              K: fmt::Debug,
     {
         self._solve(Some(1)).pop()
     }
 }
 
-pub struct ProblemBuilder<'a, V, K>(Problem<'a, V, K>);
+pub struct ProblemBuilder<'p, V, K>(Problem<'p, V, K>);
 
-impl<'a, V, K: Eq + Hash + Clone> ProblemBuilder<'a, V, K> {
-    fn new() -> ProblemBuilder<'a, V, K> {
+impl<'p, V, K: Eq + Hash + Clone> ProblemBuilder<'p, V, K> {
+    fn new() -> ProblemBuilder<'p, V, K> {
         ProblemBuilder(
             Problem{
                 keys: Vec::new(),
@@ -249,20 +316,20 @@ impl<'a, V, K: Eq + Hash + Clone> ProblemBuilder<'a, V, K> {
             })
     }
 
-    pub fn add_variable(mut self, name: K, domain: Vec<&'a V>, value: Option<&'a V>) -> Self
+    pub fn add_variable(mut self, name: K, static_filter: Vec<&'p V>, initial: Option<&'p V>) -> Self
     {
         self.0.keys.push(name);
-        self.0.variables.push(value);
-        self.0.domains.push(domain);
+        self.0.variables.push(initial);
+        self.0.domains.push(static_filter);
         self
     }
 
-    pub fn add_constraint(mut self, cons: Constraint<'a,V>) -> Self {
+    pub fn add_constraint(mut self, cons: Constraint<'p,V,K>) -> Self {
         self.0.constraints.push(cons);
         self
     }
 
-    pub fn finish(self) -> Problem<'a, V, K> {
+    pub fn finish(self) -> Problem<'p,V, K> {
         self.0
     }
 }
@@ -274,12 +341,9 @@ mod tests {
     fn test_solver_find_pairs() {
         use super::*;
         let domain = Domain::new(vec![1,2,3]);
-        let mut problem: Problem<_, _> = Problem::build()
+        let problem: Problem<_, _> = Problem::build()
             .add_variable(String::from("Left"), domain.all(), None)
             .add_variable(String::from("Right"), domain.all(), None)
-            .add_constraint(|assign: &Variables<i32>| {
-                assign[0] == assign[1]
-            })
             .finish();
 
         let solutions: Vec<Solution<i32, _>> = vec![
@@ -295,12 +359,9 @@ mod tests {
     fn test_solver_find_pairs_with_initial() {
         use super::*;
         let domain = Domain::new(vec![1,2,3]);
-        let mut problem: Problem<_, _> = Problem::build()
+        let problem: Problem<_, _> = Problem::build()
             .add_variable("Left".to_string(), domain.all(), None)
             .add_variable("Right".to_string(), domain.all(), Some(&2))
-            .add_constraint( |assign: &Variables<i32>| {
-                assign[0] == assign[1]
-            })
             .finish();
 
         let solutions: Vec<Solution<i32, String>> = vec![

web/src/main.rs

@@ -100,9 +100,8 @@ mod api {
         for (var, dom, ini) in template::Template::generate_variables(&domain) {
             problem = problem.add_variable(var, dom, ini);
         }
-        let mut problem = problem
-            .add_constraint(|_| true)
-            .finish();
+        let problem = problem.finish();
+        
         if let Some(one_result) = problem.solve_one() {
             Json(TemplateObject {
                 items: one_result
@@ -127,8 +126,6 @@ mod api {
             solver::{Domain, Problem}
         };
 
-        println!("{:?}", partial);
-        println!("Building problem");
         let possible_values = recipes::load_all(&conn);
         let domain = Domain::new(possible_values);
         let mut problem = Problem::build();
@@ -144,16 +141,15 @@ mod api {
                             && slot.key.1 == format!("{:?}",var.1)
                         {
                             let id = slot.value.as_ref().unwrap().id;
-                            println!("found initial : recipe with id {}", id);
+                            //println!("found initial : recipe with id {}", id);
                             Some(id)
                         } else {
                             None
                         }
                     });
             let ini = if let Some(id) = initial_id {
-                // Not working because we're capturing `id`
                 let new_ini = domain.find(|r| {r.id == id});
-                println!("Overrided {:?}", new_ini);
+                //println!("Overrided {:?}", new_ini);
                 new_ini
             } else {
                 ini
@@ -161,9 +157,8 @@ mod api {
             // If found, override initial value
             problem = problem.add_variable(var, dom, ini);
         };
-        let mut problem = problem
-            .add_constraint(|_| true)
-            .finish();
+        let problem = problem.finish();
+
         if let Some(one_result) = problem.solve_one() {
             Json(TemplateObject {
                 items: one_result

web/vue/src/components/Planner.vue

@@ -120,12 +120,11 @@ export default {
         body,
       })
         .then((res) => {
-          this.is_loading = false;
           return res.json();}
         )
         .then((data) => this.template.updateJson(data))
         .catch((err) => console.error(err));
-
+      this.is_loading = false;
     },
     unsetMeal: function(mealKey) {
       let idx = this.template.findIndexByKey(mealKey);