1 files changed, 11 insertions, 1 deletions
diff --git a/Logic.dcl b/Logic.dcl
index 90d579b..bf76859 100644
--- a/Logic.dcl
+++ b/Logic.dcl
@@ -40,6 +40,14 @@ isEquiv :: Expr -> Bool
 instance toString Op1
 instance toString Op2
 instance toString Expr
+instance toString TruthTable
+
+instance == Op1
+instance < Op1
+instance == Op2
+instance < Op2
+instance == Expr
+instance < Expr                             // To sort by unrigorous 'complexity'; e.g. in truthtables
 
 binds_stronger :: Op2 Op2 -> Bool           // True iff arg1 stronger binds than arg2
 
@@ -50,5 +58,7 @@ substitute :: AtomOption Expr -> Expr       // Substitute all atomic expressions
 substitute_all :: [AtomOption] Expr -> Expr // Same, for multiple options
 eval :: Expr -> [Bool]                      // Evaluate to a simpler form
 
-instance toString TruthTable
+subexprs :: Expr -> [Expr]                  // Subexpressions of an expression
+sorted_subexprs :: (Expr -> [Expr])         // Similar, but roughly sorted by complexity
+truthtable :: Expr -> TruthTable            // Truthtable from an expression