Fix bug in printing of FSTRIPS instances. Closes #69

src/tarski/io/fstrips.py

@@ -1,10 +1,11 @@
 import logging
 from collections import defaultdict
+from typing import Optional, List
 
 from .common import load_tpl
 from ..model import ExtensionalFunctionDefinition
 from ..syntax import Tautology, Contradiction, Atom, CompoundTerm, CompoundFormula, QuantifiedFormula, \
-    Term, Variable, Constant, Formula
+    Term, Variable, Constant, Formula, symref
 from ..syntax.sorts import parent, Interval, ancestors
 
 from ._fstrips.common import tarski_to_pddl_type, get_requirements_string
@@ -150,12 +151,18 @@ def __init__(self, problem):
         self.problem = problem
         self.lang = problem.language
 
-    def write(self, domain_filename, instance_filename, domain_constants=None):
+    def write(self, domain_filename, instance_filename, domain_constants: Optional[List[Constant]] = None):
         domain_constants = domain_constants or []
         self.write_domain(domain_filename, domain_constants)
         self.write_instance(instance_filename, domain_constants)
 
-    def print_domain(self, constant_objects=None):
+    def print_domain(self, constant_objects: Optional[List[Constant]] = None):
+        """ Generate the PDDL string representation that would correspond to the domain.pddl file of the current
+        planning problem.
+        The parameter `constant_objects` is used to determine which of the PDDL objects are printed as "PDDL domain
+        constants", and which as "PDDL instance objects", which is something that cannot be determined from the problem
+        information alone. If `constant_objects` is None, all objects are considered instance objects.
+        """
         tpl = load_tpl("fstrips_domain.tpl")
         content = tpl.format(
             header_info="",
@@ -166,20 +173,26 @@ def print_domain(self, constant_objects=None):
             predicates=self.get_predicates(),
             actions=self.get_actions(),
             derived=self.get_derived_predicates(),
-            constants=print_objects(constant_objects if constant_objects else set()),
+            constants=print_objects(constant_objects if constant_objects else []),
         )
         return content
 
     def write_domain(self, filename, constant_objects):
         with open(filename, 'w') as file:
             file.write(self.print_domain(constant_objects))
 
-    def print_instance(self, constant_objects=None):
+    def print_instance(self, constant_objects: Optional[List[Constant]] = None):
+        """ Generate the PDDL string representation that would correspond to the instance.pddl file of the current
+        planning problem.
+        The parameter `constant_objects` is used to determine which of the PDDL objects are printed as "PDDL domain
+        constants", and which as "PDDL instance objects", which is something that cannot be determined from the problem
+        information alone. If `constant_objects` is None, all objects are considered instance objects.
+        """
         tpl = load_tpl("fstrips_instance.tpl")
 
         # Only objects which are not declared in the domain file need to be printed in the instance file
-        constant_objs_set = set(constant_objects) if constant_objects else set()
-        instance_objects = [c for c in self.problem.language.constants() if c not in constant_objs_set]
+        constants = {symref(c) for c in constant_objects} if constant_objects else set()
+        instance_objects = [c for c in self.problem.language.constants() if symref(c) not in constants]
 
         content = tpl.format(
             header_info="",

tests/io/test_fstrips_writer.py

@@ -20,13 +20,7 @@ def write_problem(problem):
 
 def get_bw_elements():
     problem = generate_small_fstrips_bw_problem()
-    lang = problem.language
-    # writer = FstripsWriter(problem)
-
-    loc = lang.get_function("loc")
-    clear = lang.get_predicate("clear")
-    b1 = lang.get_constant("b1")
-    table = lang.get_constant("table")
+    loc, clear, b1, table = problem.language.get("loc", "clear", "b1", "table")
     return problem, loc, clear, b1, table
 
 
@@ -60,10 +54,6 @@ def test_effect_writing():
     assert s6 == "(forall (?b - block) (when (clear ?b) (assign (loc ?b) table)))"
 
 
-# def test_atom_writing():
-#     pass
-
-
 def test_objects_writing():
     problem, _, _, _, _ = get_bw_elements()
     assert print_objects(problem.language.constants()) == "b1 b2 b3 b4 - block\n        table - place"
@@ -82,6 +72,30 @@ def test_gridworld_writing():
     write_problem(problem)
 
 
+def test_blocksworld_writing():
+    problem, _, _, _, _ = get_bw_elements()
+    write_problem(problem)
+
+
+def test_blocksworld_writing_with_different_constants():
+    problem, loc, clear, b1, table = get_bw_elements()
+    writer = FstripsWriter(problem)
+    instance_model_string = writer.print_instance()
+    domain_model_string = writer.print_domain()
+    assert "b1" not in domain_model_string
+    assert "b1 b2 b3 b4 - block\n        table - place" in instance_model_string
+
+    constant_objects = [b1, table]
+    instance_model_string = writer.print_instance(constant_objects=constant_objects)
+    domain_model_string = writer.print_domain(constant_objects=constant_objects)
+
+    assert "b1 - block" in domain_model_string
+    assert "table - place" in domain_model_string
+    assert """(:objects
+        b2 b3 b4 - block
+    )""" in instance_model_string
+
+
 def test_action_costs_numeric_fluents_requirements():
     problem = parcprinter.create_small_task()
     writer = FstripsWriter(problem)