From 5d4e86dff3218a861ede8ee5a83c4ac17bce0161 Mon Sep 17 00:00:00 2001
From: Niklas Gruhn <niklas@gruhn.me>
Date: Sun, 28 Apr 2024 23:22:46 +0200
Subject: [PATCH] AffineExpr: set constraint operator precedence

---
 src/Theory/LinearArithmatic/Constraint.hs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/Theory/LinearArithmatic/Constraint.hs b/src/Theory/LinearArithmatic/Constraint.hs
index bd6682d..fea6c85 100644
--- a/src/Theory/LinearArithmatic/Constraint.hs
+++ b/src/Theory/LinearArithmatic/Constraint.hs
@@ -62,10 +62,20 @@ instance Num AffineExpr where
   negate (AffineExpr constant coeffs) = 
     AffineExpr (negate constant) (M.map negate coeffs)
 
+-- Same precedence as the usual comparison operators (==, <=, ...).
+-- Otherwise arithmatic expressions have to be bracketed, 
+-- e.g. like this: `(x + y) .<= 3`.
+infix 4 .==
+infix 4 .<=
+infix 4 .>=
+infix 4 .>
+infix 4 .<
+
 -- | Construct `Equals` constraint.
 (.==) :: AffineExpr -> AffineExpr -> Constraint
 (.==) lhs_expr rhs_expr = (lhs_expr - rhs_expr, Equals)
 
+
 -- | Construct `LessEquals` constraint.
 (.<=) :: AffineExpr -> AffineExpr -> Constraint
 (.<=) lhs_expr rhs_expr = (lhs_expr - rhs_expr, LessEquals)