Some minor touchup to preconditions and fix for minus.

pddl/parser/domain.lark

@@ -67,17 +67,16 @@ constant: NAME
             | GREATER_EQUAL_OP
             | LESSER_EQUAL_OP
 
-?binary_op: multi_op
-          | MINUS
+?binary_op: MINUS
           | DIVIDE
 
 ?multi_op: TIMES
          | PLUS
 
 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
+      |     LPAR MINUS f_exp+ RPAR
       |     f_head
 
 f_head:     NAME

pddl/parser/domain.py

@@ -367,7 +367,12 @@ def f_exp(self, args):
             return args[0]
         op = None
         if args[1] == Symbols.MINUS.value:
-            op = Minus
+            if len(args[2:-1]) == 1:
+                return Times(NumericValue(-1), args[2])
+            elif len(args[2:-1]) == 2:
+                op = Minus
+            else:
+                raise PDDLParsingError(f"MINUS symbol used with {len(args[2:-1])} args")
         if args[1] == Symbols.PLUS.value:
             op = Plus
         if args[1] == Symbols.TIMES.value:

tests/test_parser/test_domain.py

@@ -317,3 +317,63 @@ 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)
+                (< (- (x ?ag)) 1)
+            )
+            :effect (and (decrease (x ?ag) 1))
+        )
+    )
+    """
+    )
+    DomainParser()(domain_str)
+
+
+def test_multi_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 3) 1)
+            )
+            :effect (and (decrease (x ?ag) 1))
+        )
+    )
+    """
+    )
+    try:
+        DomainParser()(domain_str)
+    except Exception as e:
+        assert "MINUS symbol used with 3 args" in str(e)