Implement __str__ for Domain and Problem

pddl/core.py

@@ -9,12 +9,12 @@
 # license that can be found in the LICENSE file or at
 # https://opensource.org/licenses/MIT.
 #
-
 """
 Core module of the package.
 
 It contains the class definitions to build and modify PDDL domains or problems.
 """
+from textwrap import indent
 from typing import AbstractSet, Collection, Dict, Optional, Tuple, cast
 
 from pddl._validation import (
@@ -27,6 +27,14 @@
 from pddl.action import Action
 from pddl.custom_types import name as name_type
 from pddl.custom_types import namelike, parse_name, to_names, to_types  # noqa: F401
+from pddl.formatter import (
+    print_constants,
+    print_function_skeleton,
+    print_predicates_with_types,
+    print_types_or_functions_with_parents,
+    remove_empty_lines,
+    sort_and_print_collection,
+)
 from pddl.helpers.base import assert_, check, ensure, ensure_set
 from pddl.logic.base import And, Formula, is_literal
 from pddl.logic.functions import FunctionExpression, Metric, NumericFunction
@@ -148,6 +156,36 @@ def __eq__(self, other):
             and self.actions == other.actions
         )
 
+    def __str__(self) -> str:
+        """Print a PDDL domain object."""
+        result = f"(define (domain {self.name})"
+        body = ""
+        indentation = " " * 4
+        body += sort_and_print_collection("(:requirements ", self.requirements, ")\n")
+        body += print_types_or_functions_with_parents("(:types", self.types, ")\n")
+        body += print_constants("(:constants", self.constants, ")\n")
+        if self.predicates:
+            body += f"(:predicates {print_predicates_with_types(self.predicates)})\n"
+        if self.functions:
+            body += print_types_or_functions_with_parents(
+                "(:functions", self.functions, ")\n", print_function_skeleton
+            )
+        body += sort_and_print_collection(
+            "",
+            self.derived_predicates,
+            "",
+            to_string=lambda obj: str(obj) + "\n",
+        )
+        body += sort_and_print_collection(
+            "",
+            self.actions,
+            "",
+            to_string=lambda obj: str(obj) + "\n",
+        )
+        result = result + "\n" + indent(body, indentation) + "\n)"
+        result = remove_empty_lines(result)
+        return result
+
 
 class Problem:
     """A class for a PDDL problem file."""
@@ -331,3 +369,20 @@ def __eq__(self, other):
             and self.goal == other.goal
             and self.metric == other.metric
         )
+
+    def __str__(self) -> str:
+        """Print a PDDL problem object."""
+        result = f"(define (problem {self.name})"
+        body = f"(:domain {self.domain_name})\n"
+        indentation = " " * 4
+        body += sort_and_print_collection("(:requirements ", self.requirements, ")\n")
+        if self.objects:
+            body += print_constants("(:objects", self.objects, ")\n")
+        body += sort_and_print_collection(
+            "(:init ", self.init, ")\n", is_mandatory=True
+        )
+        body += f"{'(:goal ' + str(self.goal) + ')'}\n"
+        body += f"{'(:metric ' + str(self.metric) + ')'}\n" if self.metric else ""
+        result = result + "\n" + indent(body, indentation) + "\n)"
+        result = remove_empty_lines(result)
+        return result

pddl/formatter.py

@@ -11,37 +11,51 @@
 #
 
 """Formatting utilities for PDDL domains and problems."""
-from textwrap import indent
 from typing import Callable, Collection, Dict, List, Optional, TypeVar
 
-from pddl.core import Domain, Problem
 from pddl.custom_types import name
 from pddl.logic.functions import NumericFunction
 from pddl.logic.terms import Constant
 
 T = TypeVar("T", name, NumericFunction)
 
 
-def _remove_empty_lines(s: str) -> str:
+def remove_empty_lines(s: str) -> str:
     """Remove empty lines from string."""
     return "\n".join(filter(str.strip, s.splitlines()))
 
 
-def _sort_and_print_collection(
+def sort_and_print_collection(
     prefix,
     collection: Collection,
     postfix,
     to_string: Callable = str,
     is_mandatory: bool = False,
 ):
+    r"""Produce the string of a PDDL section for a collection (e.g., requirements, actions, objects, etc.).
+
+    Prefix starts the PDDL section, like "(:requirements"  or "(:actions"
+    Postfix ends the section, usually with ")\n"
+    The collection is sorted and printed as a string, using to_string to convert each element to a string.
+
+    Args:
+        prefix (str): start of the string
+        collection (Collection): the collection of entities to report as a string
+        postfix (str): the end of the string
+        to_string (Callable, optional): the function to use to convert to string. Defaults to str.
+        is_mandatory (bool, optional): if the string is mandatory even if the collection is empty. Defaults to False.
+
+    Returns:
+        str: a string with <prefix> <string of collection> <postfix>
+    """
     if len(collection) > 0:
         return prefix + " ".join(sorted(map(to_string, collection))) + postfix
     elif is_mandatory:
         return prefix + postfix
     return ""
 
 
-def _print_types_or_functions_with_parents(
+def print_types_or_functions_with_parents(
     prefix: str,
     types_dict: Dict[T, Optional[name]],
     postfix: str,
@@ -53,10 +67,10 @@ def _print_types_or_functions_with_parents(
         name_by_obj.setdefault(parent_type, []).append(obj_name)  # type: ignore
     if not bool(name_by_obj):
         return ""
-    return _print_typed_lists(prefix, name_by_obj, postfix, to_string)
+    return print_typed_lists(prefix, name_by_obj, postfix, to_string)
 
 
-def _print_constants(
+def print_constants(
     prefix, constants: Collection[Constant], postfix, to_string: Callable = str
 ):
     """Print constants in a PDDL domain."""
@@ -65,10 +79,11 @@ def _print_constants(
         term_by_type_tags.setdefault(c.type_tag, []).append(c.name)
     if not bool(term_by_type_tags):
         return ""
-    return _print_typed_lists(prefix, term_by_type_tags, postfix, to_string)
+    return print_typed_lists(prefix, term_by_type_tags, postfix, to_string)
 
 
-def _print_predicates_with_types(predicates: Collection):
+def print_predicates_with_types(predicates: Collection):
+    """Generate a string with predicates with type tags for the :predicates section."""
     result = ""
     for p in sorted(predicates):
         if p.arity == 0:
@@ -89,7 +104,7 @@ def _print_predicates_with_types(predicates: Collection):
     return result.strip()
 
 
-def _print_function_skeleton(function: NumericFunction) -> str:
+def print_function_skeleton(function: NumericFunction) -> str:
     """Callable to print a function skeleton with type tags."""
     result = ""
     if function.arity == 0:
@@ -106,7 +121,7 @@ def _print_function_skeleton(function: NumericFunction) -> str:
     return result
 
 
-def _print_typed_lists(
+def print_typed_lists(
     prefix,
     names_by_obj: Dict[Optional[T], List[name]],
     postfix,
@@ -139,50 +154,11 @@ def _print_typed_lists(
     return result
 
 
-def domain_to_string(domain: Domain) -> str:
+def domain_to_string(domain) -> str:
     """Print a PDDL domain object."""
-    result = f"(define (domain {domain.name})"
-    body = ""
-    indentation = " " * 4
-    body += _sort_and_print_collection("(:requirements ", domain.requirements, ")\n")
-    body += _print_types_or_functions_with_parents("(:types", domain.types, ")\n")
-    body += _print_constants("(:constants", domain.constants, ")\n")
-    if domain.predicates:
-        body += f"(:predicates {_print_predicates_with_types(domain.predicates)})\n"
-    if domain.functions:
-        body += _print_types_or_functions_with_parents(
-            "(:functions", domain.functions, ")\n", _print_function_skeleton
-        )
-    body += _sort_and_print_collection(
-        "",
-        domain.derived_predicates,
-        "",
-        to_string=lambda obj: str(obj) + "\n",
-    )
-    body += _sort_and_print_collection(
-        "",
-        domain.actions,
-        "",
-        to_string=lambda obj: str(obj) + "\n",
-    )
-    result = result + "\n" + indent(body, indentation) + "\n)"
-    result = _remove_empty_lines(result)
-    return result
+    return str(domain)
 
 
-def problem_to_string(problem: Problem) -> str:
+def problem_to_string(problem) -> str:
     """Print a PDDL problem object."""
-    result = f"(define (problem {problem.name})"
-    body = f"(:domain {problem.domain_name})\n"
-    indentation = " " * 4
-    body += _sort_and_print_collection("(:requirements ", problem.requirements, ")\n")
-    if problem.objects:
-        body += _print_constants("(:objects", problem.objects, ")\n")
-    body += _sort_and_print_collection(
-        "(:init ", problem.init, ")\n", is_mandatory=True
-    )
-    body += f"{'(:goal ' + str(problem.goal) + ')'}\n"
-    body += f"{'(:metric ' + str(problem.metric) + ')'}\n" if problem.metric else ""
-    result = result + "\n" + indent(body, indentation) + "\n)"
-    result = _remove_empty_lines(result)
-    return result
+    return str(problem)