Fix(core): Ensure Python 3.8+ compatibility by using ast.Constant

.github/workflows/pythonapp.yml

@@ -13,11 +13,11 @@ jobs:
         runs-on: ubuntu-latest
         strategy:
             matrix:
-                python-version: [3.9]
+                python-version: [3.9, 3.14]
         steps:
-            - uses: actions/checkout@v2
+            - uses: actions/checkout@v4
             - name: Set up Python ${{ matrix.python-version }}
-              uses: actions/setup-python@v1
+              uses: actions/setup-python@v5
               with:
                   python-version: ${{ matrix.python-version }}
             - name: Display Python version

hyperpyyaml/core.py

@@ -8,6 +8,7 @@
 
 import re
 import ast
+import sys
 import yaml
 import copy
 import pydoc
@@ -715,9 +716,18 @@ def _ast_eval(node):
         ast.Pow: op.pow,
         ast.Mod: op.mod,
     }
-    if isinstance(node, ast.Num):  # <number>
-        return node.n
-    elif isinstance(node, ast.BinOp):  # <left> <operator> <right>
+
+    # Compatibility check for Python versions
+    # In Python 3.8, ast.Num was deprecated and replaced by ast.Constant.
+    if sys.version_info >= (3, 8): 
+        if isinstance(node, ast.Constant):  # <number>, <string>, <bool>, <None>
+            return node.value
+    else:
+        # For Python versions older than 3.8
+        if isinstance(node, ast.Num):  # <number>
+            return node.n
+
+    if isinstance(node, ast.BinOp):  # <left> <operator> <right>
         return ops[type(node.op)](_ast_eval(node.left), _ast_eval(node.right))
     elif isinstance(node, ast.UnaryOp):  # <operator> <operand> e.g., -1
         return ops[type(node.op)](_ast_eval(node.operand))