Compatibility for python 3.7

dace/symbolic.py

@@ -1,6 +1,7 @@
 # Copyright 2019-2024 ETH Zurich and the DaCe authors. All rights reserved.
 import ast
 from functools import lru_cache
+import sys
 import sympy
 import pickle
 import re
@@ -982,6 +983,32 @@ def _process_is(elem: Union[Is, IsNot]):
     return expr
 
 
+# Depending on the Python version we need to handle different AST nodes to correctly interpret and detect falsy / truthy
+# values.
+if sys.version_info < (3, 8):
+    _SimpleASTNode = (ast.Constant, ast.Name, ast.NameConstant, ast.Num)
+    _SimpleASTNodeT = Union[ast.Constant, ast.Name, ast.NameConstant, ast.Num]
+
+    def __comp_convert_truthy_falsy(node: _SimpleASTNodeT):
+        if isinstance(node, ast.Num):
+            node_val = node.n
+        elif isinstance(node, ast.Name):
+            node_val = node.id
+        else:
+            node_val = node.value
+        return ast.copy_location(ast.NameConstant(bool(node_val)), node)
+else:
+    _SimpleASTNode = (ast.Constant, ast.Name)
+    _SimpleASTNodeT = Union[ast.Constant, ast.Name]
+
+    def __comp_convert_truthy_falsy(node: _SimpleASTNodeT):
+        return ast.copy_location(ast.Constant(bool(node.value)), node)
+
+# Convert simple AST node (constant) into a falsy / truthy. Anything other than 0, None, and an empty string '' is
+# considered a truthy, while the listed exceptions are considered falsy values - following the semantics of Python's
+# bool() builtin.
+_convert_truthy_falsy = __comp_convert_truthy_falsy
+
 class PythonOpToSympyConverter(ast.NodeTransformer):
     """ 
     Replaces various operations with the appropriate SymPy functions to avoid non-symbolic evaluation.
@@ -1078,10 +1105,10 @@ def visit_Compare(self, node: ast.Compare):
 
         if self.interpret_numeric_booleans:
             # Ensure constant values in boolean comparisons are interpreted als booleans.
-            if isinstance(node.left, ast.Compare) and isinstance(node.comparators[0], ast.Constant):
-                arguments[1] = ast.copy_location(ast.Constant(bool(node.comparators[0].value)), node.comparators[0])
-            elif isinstance(node.left, ast.Constant) and isinstance(node.comparators[0], ast.Compare):
-                arguments[0] = ast.copy_location(ast.Constant(bool(node.left.value)), node.left)
+            if isinstance(node.left, ast.Compare) and isinstance(node.comparators[0], _SimpleASTNode):
+                arguments[1] = _convert_truthy_falsy(node.comparators[0])
+            elif isinstance(node.left, _SimpleASTNode) and isinstance(node.comparators[0], ast.Compare):
+                arguments[0] = _convert_truthy_falsy(node.left)
 
         func_node = ast.copy_location(ast.Name(id=self._ast_to_sympy_comparators[type(op)], ctx=ast.Load()), node)
         new_node = ast.Call(func=func_node, args=[self.visit(arg) for arg in arguments], keywords=[])