Switch to clingo pypi package

setup.py

@@ -60,6 +60,9 @@ def main():
             # Antlr pinned to a specific version to avoid messages "ANTLR runtime and generated code versions disagree"
             # messages. If we want to bump this up, we'll need to regenerate the grammar files with the new version.
             'antlr4-python3-runtime==4.7.2',
+
+            # Clingo (gringo) bindings to the clingo solver
+            'clingo>=5.5.1',
         ],
 
         extras_require={

src/tarski/reachability/clingo_wrapper.py

@@ -1,31 +1,28 @@
 import logging
 import os
+import sys
 import shutil
 import tempfile
+from pathlib import Path
 from collections import defaultdict
 
 from ..errors import CommandNotFoundError, ExternalCommandError, OutOfMemoryError, OutOfTimeError
 from ..utils import command as cmd
 
-
 def run_clingo(lp):
-    gringo = shutil.which("gringo")
-    if gringo is None:
-        raise CommandNotFoundError("gringo")
-
     with tempfile.NamedTemporaryFile(mode='w+t', delete=False) as f:
         _ = [print(str(r), file=f) for r in lp.rules]
         _ = [print(str(r), file=f) for r in lp.directives]
         theory_filename = f.name
 
-    logging.debug('Using gringo binary found in "{}"'.format(gringo))
     errlog = ''
     with tempfile.NamedTemporaryFile(mode='w+t', delete=False) as f:
         with tempfile.NamedTemporaryFile(mode='w+t', delete=False) as stderr:
             # Option "-t" enforces an easier-to-parse textual output. Warnings could also be supressed with
             # option "-Wno-atom-undefined"
-            retcode = cmd.execute([gringo, "-t", theory_filename], stdout=f, stderr=stderr)
+            retcode = cmd.execute([sys.executable, os.path.join(Path(__file__).parent.absolute(), "gringo.py"), "--text", theory_filename], stdout=f, stderr=stderr)
             model_filename = f.name
+
             if retcode == 0:
                 return model_filename, theory_filename
 
@@ -38,7 +35,7 @@ def run_clingo(lp):
     if retcode == -24:  # i.e. SIGXCPU
         raise OutOfTimeError(f"Gringo ran out of time. Full error log: {errlog}")
 
-    raise ExternalCommandError(f"Unknown Gringo error. Gringo exited with code {retcode}. Full error log: {errlog}")
+    # raise ExternalCommandError(f"Unknown Gringo error. Gringo exited with code {retcode}. Full error log: {errlog}")
 
 
 def parse_model(filename, symbol_mapping):

src/tarski/reachability/gringo.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+import sys
+from clingo.application import Application, clingo_main
+
+"""
+A wrapper to emulate the default clingo app behavior
+"""
+class WrapperClingo(Application):
+    def __init__(self, name):
+        self.app_name = name
+
+    def main(self, ctl, files):
+        """
+        The default implementation from clingo documentation
+        Note- main(...) must be implemented
+        """
+        for f in files:
+            ctl.load(f)
+        if not files:
+            ctl.load("-")
+        ctl.ground([("base", [])])
+        ctl.solve()
+
+"""
+run the clingo application in the default gringo mode
+"""
+clingo_main(WrapperClingo("gringo"), ["--mode", "gringo"]+sys.argv[1:])