From e1227b51f45386490314ad0456cb861e00def4bb Mon Sep 17 00:00:00 2001
From: Christian Muise <christian.muise@gmail.com>
Date: Thu, 28 Dec 2023 10:32:21 -0500
Subject: [PATCH] Some minor touchup to preconditions and fix for minus.

---
 pddl/parser/domain.lark          |  6 ++----
 pddl/parser/domain.py            |  7 ++++++-
 pddl/parser/problem.py           |  7 ++++++-
 tests/test_parser/test_domain.py | 28 ++++++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/pddl/parser/domain.lark b/pddl/parser/domain.lark
index 6703c10..6784fa2 100644
--- a/pddl/parser/domain.lark
+++ b/pddl/parser/domain.lark
@@ -67,8 +67,7 @@ constant: NAME
             | GREATER_EQUAL_OP
             | LESSER_EQUAL_OP
 
-?binary_op: multi_op
-          | MINUS
+?binary_op: MINUS
           | DIVIDE
 
 ?multi_op: TIMES
@@ -76,8 +75,7 @@ constant: NAME
 
 f_exp:      NUMBER
       |     LPAR binary_op f_exp f_exp RPAR
-      |     LPAR multi_op f_exp f_exp+ RPAR
-      |     LPAR MINUS f_exp RPAR
+      |     LPAR multi_op f_exp+ RPAR
       |     f_head
 
 f_head:     NAME
diff --git a/pddl/parser/domain.py b/pddl/parser/domain.py
index e08bfdd..afd2aa1 100644
--- a/pddl/parser/domain.py
+++ b/pddl/parser/domain.py
@@ -462,8 +462,13 @@ def __init__(self):
 
     def __call__(self, text):
         """Call."""
+        def handle_debug(e):
+            print("\nLocation of parse error:")
+            print(e.get_context(text))
+            print(e.interactive_parser.pretty())
+            print()
         sys.tracebacklimit = 0  # noqa
-        tree = self._parser.parse(text)
+        tree = self._parser.parse(text, on_error=handle_debug)
         sys.tracebacklimit = None  # noqa
         formula = self._transformer.transform(tree)
         return formula
diff --git a/pddl/parser/problem.py b/pddl/parser/problem.py
index 2ca8856..2d14f58 100644
--- a/pddl/parser/problem.py
+++ b/pddl/parser/problem.py
@@ -244,8 +244,13 @@ def __init__(self):
 
     def __call__(self, text):
         """Call."""
+        def handle_debug(e):
+            print("\nLocation of parse error:")
+            print(e.get_context(text))
+            print(e.interactive_parser.pretty())
+            print()
         sys.tracebacklimit = 0  # noqa
-        tree = self._parser.parse(text)
+        tree = self._parser.parse(text, on_error=handle_debug)
         sys.tracebacklimit = None  # noqa
         formula = self._transformer.transform(tree)
         return formula
diff --git a/tests/test_parser/test_domain.py b/tests/test_parser/test_domain.py
index b41b480..974d86d 100644
--- a/tests/test_parser/test_domain.py
+++ b/tests/test_parser/test_domain.py
@@ -317,3 +317,31 @@ def test_check_action_costs_requirement_with_total_cost() -> None:
         match=r"action costs requirement is not specified, but the total-cost function is specified.",
     ):
         DomainParser()(domain_str)
+
+
+def test_minus_in_precondition() -> None:
+    """Check minus in precondition."""
+    domain_str = dedent(
+        """
+    (define (domain cant-subtract-in-precondition)
+        (:requirements :strips :typing :numeric-fluents)
+
+        (:types
+            agent - object
+        )
+
+        (:functions
+            (x ?l - agent)
+        )
+
+        (:action move-south
+            :parameters (?ag - agent)
+            :precondition  (and
+                (< (- (x ?ag) 1) 1)
+            )
+            :effect (and (decrease (x ?ag) 1))
+        )
+    )
+    """
+    )
+    DomainParser()(domain_str)