concretizer: don't use clingo.Symbol for setup (#49650)

Since we moved from creating clingo symbols directly to constructing a pure string
representation of the program, we don't need to make `AspFunctions` into symbols before
turning them into strings. We can just write strings like clingo would.

This cuts about 25% off the setup time by avoiding an unnecessary round trip.

- [x] create strings directly from `AspFunctions`
- [x] remove unused `symbol()` method on `AspFunction`
- [x] setup no longer tries to call `symbol()`

Signed-off-by: Todd Gamblin <tgamblin@llnl.gov>
Signed-off-by: Greg Becker <becker33@llnl.gov>

---------

Signed-off-by: Todd Gamblin <tgamblin@llnl.gov>
Co-authored-by: Greg Becker <becker33@llnl.gov>

lib/spack/spack/solver/asp.py

@@ -3432,8 +3432,7 @@ def __init__(self):
         self.asp_problem = []
 
     def fact(self, atom: AspFunction) -> None:
-        symbol = atom.symbol() if hasattr(atom, "symbol") else atom
-        self.asp_problem.append(f"{str(symbol)}.\n")
+        self.asp_problem.append(f"{atom}.\n")
 
     def append(self, rule: str) -> None:
         self.asp_problem.append(rule)

lib/spack/spack/solver/core.py

@@ -31,16 +31,19 @@ class AspObject:
     """Object representing a piece of ASP code."""
 
 
-def _id(thing: Any) -> Union[str, AspObject]:
+def _id(thing: Any) -> Union[str, int, AspObject]:
     """Quote string if needed for it to be a valid identifier."""
-    if isinstance(thing, AspObject):
+    if isinstance(thing, bool):
+        return f'"{thing}"'
+    elif isinstance(thing, (AspObject, int)):
         return thing
-    elif isinstance(thing, bool):
-        return f'"{str(thing)}"'
-    elif isinstance(thing, int):
-        return str(thing)
     else:
-        return f'"{str(thing)}"'
+        if isinstance(thing, str):
+            # escape characters that cannot be in clingo strings
+            thing = thing.replace("\\", r"\\")
+            thing = thing.replace("\n", r"\n")
+            thing = thing.replace('"', r"\"")
+        return f'"{thing}"'
 
 
 class AspVar(AspObject):
@@ -90,26 +93,9 @@ def __call__(self, *args: Any) -> "AspFunction":
         """
         return AspFunction(self.name, self.args + args)
 
-    def _argify(self, arg: Any) -> Any:
-        """Turn the argument into an appropriate clingo symbol"""
-        if isinstance(arg, bool):
-            return clingo().String(str(arg))
-        elif isinstance(arg, int):
-            return clingo().Number(arg)
-        elif isinstance(arg, AspFunction):
-            return clingo().Function(arg.name, [self._argify(x) for x in arg.args], positive=True)
-        elif isinstance(arg, AspVar):
-            return clingo().Variable(arg.name)
-        return clingo().String(str(arg))
-
-    def symbol(self):
-        """Return a clingo symbol for this function"""
-        return clingo().Function(
-            self.name, [self._argify(arg) for arg in self.args], positive=True
-        )
-
     def __str__(self) -> str:
-        return f"{self.name}({', '.join(str(_id(arg)) for arg in self.args)})"
+        args = f"({','.join(str(_id(arg)) for arg in self.args)})"
+        return f"{self.name}{args}"
 
     def __repr__(self) -> str:
         return str(self)