fix: problem optionally accepts requirements

pddl/parser/problem.lark

@@ -1,9 +1,12 @@
 start: problem
 
-problem:           LPAR DEFINE problem_def problem_domain [requirements] [objects] init goal RPAR
+problem:           LPAR DEFINE problem_def problem_domain [problem_requirements] [objects] init goal RPAR
 problem_def:       LPAR PROBLEM NAME RPAR
 problem_domain:    LPAR DOMAIN_P NAME RPAR
 
+problem_requirements: LPAR REQUIREMENTS require_key+ RPAR
+
+
 objects:   LPAR OBJECTS typed_list_name RPAR
 
 init:                  LPAR INIT init_el* RPAR
@@ -29,7 +32,7 @@ GOAL: ":goal"
 %ignore COMMENT
 
 %import .common.COMMENT -> COMMENT
-%import .domain.requirements -> requirements
+%import .domain.require_key -> require_key
 %import .domain.typed_list_name -> typed_list_name
 %import .domain.predicate -> predicate
 %import .common.NAME -> NAME

pddl/parser/problem.py

@@ -57,7 +57,7 @@ def problem_domain(self, args):
         """Process the 'problem_domain' rule."""
         return "domain_name", args[2]
 
-    def requirements(self, args):
+    def problem_requirements(self, args):
         """Process the 'requirements' rule."""
         return "requirements", {Requirements(r[1:]) for r in args[2:-1]}
 

tests/test_parser/test_problem.py

@@ -12,11 +12,13 @@
 
 """This module contains the tests for the domain parser."""
 from pathlib import Path
+from textwrap import dedent
 
 import pytest
 from pytest import lazy_fixture  # type:ignore  # noqa
 
-from pddl.core import Problem
+from pddl.core import Problem, Requirements
+from pddl.parser.problem import ProblemParser
 from tests.conftest import BLOCKSWORLD_FILES, BLOCKSWORLD_FOND_FILES, PROBLEM_FILES
 
 
@@ -45,3 +47,20 @@ def test_check_problem_parser_output(problem_parser, pddl_file: Path, expected_p
 
     assert isinstance(actual_problem, Problem)
     assert actual_problem == expected_problem
+
+
+def test_problem_requirements_section_parsed() -> None:
+    """Check that the requirements section is parsed correctly."""
+    problem_str = dedent(
+        """
+        (define (problem test-problem)
+            (:domain test-domain)
+            (:requirements :typing)
+            (:objects a b c)
+            (:init (p b b b))
+            (:goal (g a a a))
+        )"""
+    )
+    problem = ProblemParser()(problem_str)
+
+    assert problem.requirements == {Requirements.TYPING}