Remove Ord bounds on types

They belong on the methods, a lá `HashMap`.

Author: ecstatic-morse

src/relation.rs

@@ -11,8 +11,8 @@ use crate::{
 /// A relation represents a fixed set of key-value pairs. In many places in a
 /// Datalog computation we want to be sure that certain relations are not able
 /// to vary (for example, in antijoins).
-#[derive(Clone)]
-pub struct Relation<Tuple: Ord> {
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Relation<Tuple> {
     /// Sorted list of distinct tuples.
     pub elements: Vec<Tuple>,
 }

src/variable.rs

@@ -36,7 +36,7 @@ pub(crate) trait VariableTrait {
 /// of performance. Such a variable cannot be relied on to terminate iterative computation,
 /// and it is important that any cycle of derivations have at least one de-duplicating
 /// variable on it.
-pub struct Variable<Tuple: Ord> {
+pub struct Variable<Tuple> {
     /// Should the variable be maintained distinctly.
     pub(crate) distinct: bool,
     /// A useful name for the variable.
@@ -251,7 +251,7 @@ impl<Tuple: Ord> Variable<Tuple> {
     }
 }
 
-impl<Tuple: Ord> Clone for Variable<Tuple> {
+impl<Tuple> Clone for Variable<Tuple> {
     fn clone(&self) -> Self {
         Variable {
             distinct: self.distinct,