feat: add PredicatesDef definition and validation

pddl/core.py

@@ -23,6 +23,7 @@
 from pddl.custom_types import namelike, parse_name, to_names, to_types  # noqa: F401
 from pddl.definitions.base import TypesDef
 from pddl.definitions.constants_def import ConstantsDef
+from pddl.definitions.predicates_def import _PredicatesDef
 from pddl.helpers.base import assert_, check, ensure, ensure_set
 from pddl.logic.base import And, Formula, is_literal
 from pddl.logic.predicates import DerivedPredicate, Predicate
@@ -61,7 +62,9 @@ def __init__(
         self._requirements = ensure_set(requirements)
         self._types = TypesDef(types, self._requirements)
         self._constants_def = ConstantsDef(self._requirements, self._types, constants)
-        self._predicates = ensure_set(predicates)
+        self._predicates_def = _PredicatesDef(
+            self._requirements, self._types, predicates
+        )
         self._derived_predicates = ensure_set(derived_predicates)
         self._actions = ensure_set(actions)
 
@@ -70,7 +73,6 @@ def __init__(
     def _check_consistency(self) -> None:
         """Check consistency of a domain instance object."""
         checker = TypeChecker(self._types, self.requirements)
-        checker.check_type(self._predicates)
         checker.check_type(self._actions)
         _check_types_in_has_terms_objects(self._actions, self._types.all_types)  # type: ignore
         self._check_types_in_derived_predicates()
@@ -102,7 +104,7 @@ def constants(self) -> AbstractSet[Constant]:
     @property
     def predicates(self) -> AbstractSet[Predicate]:
         """Get the predicates."""
-        return self._predicates
+        return self._predicates_def.predicates
 
     @property
     def derived_predicates(self) -> AbstractSet[DerivedPredicate]:

pddl/definitions/predicates_def.py

@@ -0,0 +1,58 @@
+#
+# Copyright 2021-2023 WhiteMech
+#
+# ------------------------------
+#
+# This file is part of pddl.
+#
+# Use of this source code is governed by an MIT-style
+# license that can be found in the LICENSE file or at
+# https://opensource.org/licenses/MIT.
+#
+
+"""This module implements the ConstantsDef class to handle the constants of a PDDL domain."""
+from typing import AbstractSet, Collection, Dict, Optional
+
+from pddl.custom_types import name as name_type
+from pddl.definitions.base import TypesDef, _Definition
+from pddl.exceptions import PDDLValidationError
+from pddl.helpers.base import ensure_set
+from pddl.logic.predicates import Predicate
+from pddl.requirements import Requirements
+from pddl.validation.terms import TermsValidator
+
+
+class _PredicatesDef(_Definition):
+    """A set of predicates of a PDDL domain."""
+
+    def __init__(
+        self,
+        requirements: AbstractSet[Requirements],
+        types: TypesDef,
+        predicates: Optional[Collection[Predicate]],
+    ) -> None:
+        """Initialize the PDDL constants section validator."""
+        super().__init__(requirements, types)
+
+        self._predicates: AbstractSet[Predicate] = ensure_set(predicates)
+
+        self._check_consistency()
+
+    @property
+    def predicates(self) -> AbstractSet[Predicate]:
+        """Get the predicates."""
+        return self._predicates
+
+    def _check_consistency(self) -> None:
+        """Check consistency of the predicates definition."""
+        seen_predicates_by_name: Dict[name_type, Predicate] = {}
+        for p in self._predicates:
+            # check that no two predicates have the same name
+            if p.name in seen_predicates_by_name:
+                raise PDDLValidationError(
+                    f"these predicates have the same name: {p}, {seen_predicates_by_name[p.name]}"
+                )
+            seen_predicates_by_name[p.name] = p
+
+            # check that the terms of the predicate are consistent
+            TermsValidator(self._requirements, self._types).check_terms(p.terms)

pddl/logic/predicates.py

@@ -12,95 +12,58 @@
 
 """This class implements PDDL predicates."""
 import functools
-from typing import Collection, Dict, Generator, Sequence, Set, Tuple
+from typing import Sequence
 
 from pddl.custom_types import name as name_type
 from pddl.custom_types import namelike, parse_name
-from pddl.exceptions import PDDLValidationError
-from pddl.helpers.base import assert_, check
+from pddl.helpers.base import assert_
 from pddl.helpers.cache_hash import cache_hash
 from pddl.logic.base import Atomic, Formula
-from pddl.logic.terms import Constant, Term, _print_tag_set
+from pddl.logic.terms import Constant, Term
 from pddl.parser.symbols import Symbols
+from pddl.validation.terms import TermsValidator
 
 
-class _TermsList:
-    """
-    A class wrapper for validating sequences of terms.
-
-    Note that this is only for internal validation of terms, and not specific to any PDDL domain type hierarchy.
-    """
-
-    def __init__(self, terms_list: Collection[Term]) -> None:
-        """Initialize the terms list."""
-        self._terms = tuple(self.check_no_duplicate_iterator(terms_list))
+class _BaseAtomic(Atomic):
+    """Base class to share common code among atomic formulas classes."""
 
+    def __init__(self, *terms: Term) -> None:
+        """Initialize the atomic formula."""
+        TermsValidator.check_terms_consistency(terms)
+        self._terms = tuple(terms)
         self._is_ground: bool = all(isinstance(v, Constant) for v in self._terms)
 
     @property
-    def terms(self) -> Tuple[Term, ...]:
-        """Get the terms sequence."""
+    def terms(self) -> Sequence[Term]:
+        """Get the terms."""
         return self._terms
 
     @property
     def is_ground(self) -> bool:
         """Check whether the predicate is ground."""
         return self._is_ground
 
-    @staticmethod
-    def check_no_duplicate_iterator(
-        terms: Collection[Term],
-    ) -> Generator[Term, None, None]:
-        """
-        Iterate over terms and check that there are no duplicates.
-
-        In particular, terms with the same name must have the same type tags.
-        """
-        seen: Dict[name_type, Set[name_type]] = {}
-        for term in terms:
-            if term.name not in seen:
-                seen[term.name] = set(term.type_tags)
-            else:
-                check(
-                    seen[term.name] == set(term.type_tags),
-                    f"Term {term} occurred twice with different type tags: "
-                    f"previous type tags {_print_tag_set(seen[term.name])}, "
-                    f"new type tags {_print_tag_set(term.type_tags)}",
-                    exception_cls=PDDLValidationError,
-                )
-            yield term
-
 
 @cache_hash
 @functools.total_ordering
-class Predicate(Atomic):
+class Predicate(_BaseAtomic):
     """A class for a Predicate in PDDL."""
 
     def __init__(self, predicate_name: namelike, *terms: Term):
         """Initialize the predicate."""
         self._name = parse_name(predicate_name)
-        self._terms_list = _TermsList(terms)
+        super().__init__(*terms)
 
     @property
     def name(self) -> name_type:
         """Get the name."""
         return self._name
 
-    @property
-    def terms(self) -> Sequence[Term]:
-        """Get the terms."""
-        return self._terms_list.terms
-
     @property
     def arity(self) -> int:
         """Get the arity of the predicate."""
         return len(self.terms)
 
-    @property
-    def is_ground(self) -> bool:
-        """Check whether the predicate is ground."""
-        return self._terms_list.is_ground
-
     # TODO check whether it's a good idea...
     # TODO allow also for keyword-based replacement
     # TODO allow skip replacement with None arguments.
@@ -143,7 +106,7 @@ def __lt__(self, other):
         return super().__lt__(other)
 
 
-class EqualTo(Atomic):
+class EqualTo(_BaseAtomic):
     """Equality predicate."""
 
     def __init__(self, left: Term, right: Term):
@@ -153,11 +116,10 @@ def __init__(self, left: Term, right: Term):
         :param left: the left term.
         :param right: the right term.
         """
+        super().__init__(left, right)
         self._left = left
         self._right = right
 
-        self._terms_list = _TermsList([self._left, self._right])
-
     @property
     def left(self) -> Term:
         """Get the left operand."""

pddl/validation/base.py

@@ -11,7 +11,7 @@
 #
 
 """Base module for validators."""
-from typing import AbstractSet, Collection
+from typing import AbstractSet, Callable, Collection
 
 from pddl.custom_types import name as name_type
 from pddl.definitions.base import TypesDef
@@ -44,10 +44,10 @@ def _check_typing_requirement(self, type_tags: Collection[name_type]) -> None:
             )
 
     def _check_types_are_available(
-        self, type_tags: Collection[name_type], what: str
+        self, type_tags: Collection[name_type], what: Callable[[], str]
     ) -> None:
         """Check that the types are available in the domain."""
         if not self._types.all_types.issuperset(type_tags):
             raise PDDLValidationError(
-                f"types {sorted(type_tags)} of {what} are not in available types {self._types.all_types}"
+                f"types {sorted(type_tags)} of {what()} are not in available types {sorted(self._types.all_types)}"
             )

pddl/validation/terms.py

@@ -11,27 +11,66 @@
 #
 
 """Module for validator of terms."""
-from typing import AbstractSet, Collection
+from functools import partial
+from typing import Collection, Dict, Generator, Set
 
-from pddl.definitions.base import TypesDef
-from pddl.logic.predicates import _TermsList
-from pddl.logic.terms import Term
-from pddl.requirements import Requirements
+from pddl.custom_types import name as name_type
+from pddl.exceptions import PDDLValidationError
+from pddl.helpers.base import check
+from pddl.logic.terms import Term, _print_tag_set
 from pddl.validation.base import BaseValidator
 
 
 class TermsValidator(BaseValidator):
     """Class for validator of terms."""
 
-    def __init__(
-        self, requirements: AbstractSet[Requirements], types: TypesDef
-    ) -> None:
-        """Initialize the validator."""
-        super().__init__(requirements, types)
+    @classmethod
+    def check_terms_consistency(cls, terms: Collection[Term]):
+        """
+        Check that there are no duplicates.
+
+        This is the non-iterative version of '_check_terms_consistency_iterator'.
+        """
+        # consume the iterator
+        list(cls._check_terms_consistency_iterator(terms))
+
+    @classmethod
+    def _check_terms_consistency_iterator(
+        cls, terms: Collection[Term]
+    ) -> Generator[Term, None, None]:
+        """
+        Iterate over terms and check that terms with the same name must have the same type tags.
+
+        In particular:
+        - terms with the same name must be of the same term type (variable or constant);
+        - terms with the same name must have the same type tags.
+        """
+        seen: Dict[name_type, Set[name_type]] = {}
+        for term in terms:
+            if term.name not in seen:
+                seen[term.name] = set(term.type_tags)
+            else:
+                expected_type_tags = seen[term.name]
+                actual_type_tags = set(term.type_tags)
+                check(
+                    expected_type_tags == actual_type_tags,
+                    f"Term {term} occurred twice with different type tags: "
+                    f"previous type tags {_print_tag_set(expected_type_tags)}, "
+                    f"new type tags {_print_tag_set(actual_type_tags)}",
+                    exception_cls=PDDLValidationError,
+                )
+            yield term
 
     def check_terms(self, terms: Collection[Term]) -> None:
         """Check the terms."""
-        terms_iter = _TermsList.check_no_duplicate_iterator(terms)
+        terms_iter = self._check_terms_consistency_iterator(terms)
         for term in terms_iter:
             self._check_typing_requirement(term.type_tags)
-            self._check_types_are_available(term.type_tags, "terms")
+            self._check_types_are_available(
+                term.type_tags, partial(self._terms_to_string, terms)
+            )
+
+    @classmethod
+    def _terms_to_string(cls, terms: Collection[Term]) -> str:
+        """Convert terms to string for error messages."""
+        return "terms ['" + "', '".join(map(str, terms)) + "']"