More Datalog

1 files changed, 13 insertions, 61 deletions

diff --git a/crates/elfmind/src/knowledge.rs b/crates/elfmind/src/knowledge.rs
index 3b90dee..cbcce28 100644
--- a/crates/elfmind/src/knowledge.rs
+++ b/crates/elfmind/src/knowledge.rs
@@ -1,12 +1,15 @@
-use std::collections::{HashMap, HashSet};
-use itertools::Itertools;
+pub mod relation;
+pub use relation::*;
 
-use enum_map::{Enum, EnumMap};
+use crate::time::*;
+use crate::item::*;
+use crate::character::*;
 
-use crate::item::Item;
-use crate::character::Character;
+use std::collections::{HashMap, HashSet};
+use itertools::Itertools;
 
-type Time = u64;
+use enum_map::EnumMap;
+use strum::IntoDiscriminant;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Var { index: u64 }
@@ -100,57 +103,6 @@ impl<T: Clone + TryFrom<Value>> Hole<T> {
     }
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Enum)]
-pub enum RelationSort {
-    HasItem,
-    UsedItemAt,
-    TimeIs,
-    FriendOf,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub enum Relation {
-    HasItem(Hole<Character>, Hole<Item>),
-    UsedItemAt(Hole<Character>, Hole<Item>, Hole<Time>),
-    TimeIs(Hole<Time>),
-    FriendOf(Hole<Character>, Hole<Character>),
-}
-impl Relation {
-    pub fn sort(&self) -> RelationSort {
-        match self {
-            Self::HasItem{..} => RelationSort::HasItem,
-            Self::UsedItemAt{..} => RelationSort::UsedItemAt,
-            Self::TimeIs{..} => RelationSort::TimeIs,
-            Self::FriendOf{..} => RelationSort::FriendOf,
-        }
-    }
-    pub fn unify(&self, other: &Self, mut u: Unification) -> Option<Unification> {
-        match (self, other) {
-            (Self::HasItem(c1, i1), Self::HasItem(c2, i2))
-              if u.unify_hole(c1, c2) && u.unify_hole(i1, i2)
-              => Some(u),
-            (Self::UsedItemAt(c1, i1, t1), Self::UsedItemAt(c2, i2, t2))
-              if u.unify_hole(c1, c2) && u.unify_hole(i1, i2) && u.unify_hole(t1, t2)
-              => Some(u),
-            (Self::TimeIs(t1), Self::TimeIs(t2))
-              if u.unify_hole(t1, t2)
-              => Some(u),
-            (Self::FriendOf(x1, y1), Self::FriendOf(x2, y2))
-              if u.unify_hole(x1, x2) && u.unify_hole(y1, y2)
-              => Some(u),
-            _ => None,
-        }
-    }
-    pub fn substitute(&self, u: &Unification) -> Self {
-        match self {
-            Self::HasItem(c, i) => Self::HasItem(c.substitute(u), i.substitute(u)),
-            Self::UsedItemAt(c, i, t) => Self::UsedItemAt(c.substitute(u), i.substitute(u), t.substitute(u)),
-            Self::TimeIs(t) => Self::TimeIs(t.substitute(u)),
-            Self::FriendOf(x, y) => Self::FriendOf(x.substitute(u), y.substitute(u)),
-        }
-    }
-}
-
 #[derive(Debug, Clone)]
 pub struct Rule {
     pub head: Relation,
@@ -169,13 +121,13 @@ impl Rule {
 
 #[derive(Debug, Default, Clone)]
 pub struct Facts {
-    facts: EnumMap<RelationSort, HashSet<Relation>>,
+    facts: EnumMap<RelationDiscriminants, HashSet<Relation>>,
 }
 impl Facts {
     pub fn add(&mut self, f: Relation) -> bool {
-        self.facts[f.sort()].insert(f)
+        self.facts[f.discriminant()].insert(f)
     }
-    pub fn with_sort(&self, s: RelationSort) -> &HashSet<Relation> {
+    pub fn with_sort(&self, s: RelationDiscriminants) -> &HashSet<Relation> {
         &self.facts[s]
     }
 }
@@ -190,7 +142,7 @@ impl Database {
     pub fn add_rule(&mut self, r: Rule) { self.rules.push(r) }
     fn apply_rule(r: &Rule, facts: &mut Facts) -> bool {
         let found: Vec<Unification> = r.body.iter()
-            .map(|r| facts.with_sort(r.sort())).multi_cartesian_product()
+            .map(|r| facts.with_sort(r.discriminant())).multi_cartesian_product()
             .filter_map(|fs| r.unify_body(&fs))
             .collect();
         let mut changed = false;