Merge pull request #1482 from brian-team/ast_deprecation_fixes

AST deprecation fixes

brian2/codegen/optimisation.py

@@ -17,7 +17,7 @@
     brian_dtype_from_dtype,
     dtype_hierarchy,
 )
-from brian2.parsing.rendering import NodeRenderer, get_node_value
+from brian2.parsing.rendering import NodeRenderer
 from brian2.utils.stringtools import get_identifiers, word_substitute
 
 from .statements import Statement
@@ -167,14 +167,14 @@ def _replace_with_zero(zero_node, node):
 
     Parameters
     ----------
-    zero_node : `ast.Num`
+    zero_node : `ast.Constant`
         The node to replace
     node : `ast.Node`
         The node that determines the type
 
     Returns
     -------
-    zero_node : `ast.Num`
+    zero_node : `ast.Constant`
         The original ``zero_node`` with its value replaced by 0 or 0.0.
     """
     # must not change the dtype of the output,
@@ -244,10 +244,7 @@ def render_node(self, node):
             else:
                 val = prefs.core.default_float_dtype(val)
             if node.dtype != "boolean":
-                if hasattr(ast, "Constant"):
-                    newnode = ast.Constant(val)
-                else:
-                    newnode = ast.Num(val)
+                newnode = ast.Constant(val)
             newnode.dtype = node.dtype
             newnode.scalar = True
             newnode.stateless = node.stateless
@@ -274,7 +271,7 @@ def render_BinOp(self, node):
         if op.__class__.__name__ == "Mult":
             for operand, other in [(left, right), (right, left)]:
                 if operand.__class__.__name__ in ["Num", "Constant"]:
-                    op_value = get_node_value(operand)
+                    op_value = operand.value
                     if op_value == 0:
                         # Do not remove stateful functions
                         if node.stateless:
@@ -289,23 +286,20 @@ def render_BinOp(self, node):
         # Handle division by 1, or 0/x
         elif op.__class__.__name__ == "Div":
             if (
-                left.__class__.__name__ in ["Num", "Constant"]
-                and get_node_value(left) == 0
+                left.__class__.__name__ in ["Num", "Constant"] and left.value == 0
             ):  # 0/x
                 if node.stateless:
                     # Do not remove stateful functions
                     return _replace_with_zero(left, node)
             if (
-                right.__class__.__name__ in ["Num", "Constant"]
-                and get_node_value(right) == 1
+                right.__class__.__name__ in ["Num", "Constant"] and right.value == 1
             ):  # x/1
                 # only simplify this if the type wouldn't be cast by the operation
                 if dtype_hierarchy[right.dtype] <= dtype_hierarchy[left.dtype]:
                     return left
         elif op.__class__.__name__ == "FloorDiv":
             if (
-                left.__class__.__name__ in ["Num", "Constant"]
-                and get_node_value(left) == 0
+                left.__class__.__name__ in ["Num", "Constant"] and left.value == 0
             ):  # 0//x
                 if node.stateless:
                     # Do not remove stateful functions
@@ -316,25 +310,22 @@ def render_BinOp(self, node):
             if (
                 left.dtype == right.dtype == "integer"
                 and right.__class__.__name__ in ["Num", "Constant"]
-                and get_node_value(right) == 1
+                and right.value == 1
             ):  # x//1
                 return left
         # Handle addition of 0
         elif op.__class__.__name__ == "Add":
             for operand, other in [(left, right), (right, left)]:
                 if (
                     operand.__class__.__name__ in ["Num", "Constant"]
-                    and get_node_value(operand) == 0
+                    and operand.value == 0
                 ):
                     # only simplify this if the type wouldn't be cast by the operation
                     if dtype_hierarchy[operand.dtype] <= dtype_hierarchy[other.dtype]:
                         return other
         # Handle subtraction of 0
         elif op.__class__.__name__ == "Sub":
-            if (
-                right.__class__.__name__ in ["Num", "Constant"]
-                and get_node_value(right) == 0
-            ):
+            if right.__class__.__name__ in ["Num", "Constant"] and right.value == 0:
                 # only simplify this if the type wouldn't be cast by the operation
                 if dtype_hierarchy[right.dtype] <= dtype_hierarchy[left.dtype]:
                     return left
@@ -349,12 +340,10 @@ def render_BinOp(self, node):
         ]:
             for subnode in [node.left, node.right]:
                 if subnode.__class__.__name__ in ["Num", "Constant"] and not (
-                    get_node_value(subnode) is True or get_node_value(subnode) is False
+                    subnode.value is True or subnode.value is False
                 ):
                     subnode.dtype = "float"
-                    subnode.value = prefs.core.default_float_dtype(
-                        get_node_value(subnode)
-                    )
+                    subnode.value = prefs.core.default_float_dtype(subnode.value)
         return node
 
 
@@ -588,10 +577,7 @@ def collect(node):
     # if the fully evaluated node is just the identity/null element then we
     # don't have to make it into an explicit term
     if x != op_null:
-        if hasattr(ast, "Constant"):
-            num_node = ast.Constant(x)
-        else:
-            num_node = ast.Num(x)
+        num_node = ast.Constant(x)
     else:
         num_node = None
     terms_primary = remaining_terms_primary
@@ -612,22 +598,16 @@ def collect(node):
         node = reduced_node([node, prod_primary], op_primary)
         if prod_inverted is not None:
             if node is None:
-                if hasattr(ast, "Constant"):
-                    node = ast.Constant(op_null_with_dtype)
-                else:
-                    node = ast.Num(op_null_with_dtype)
+                node = ast.Constant(op_null_with_dtype)
             node = ast.BinOp(node, op_inverted(), prod_inverted)
 
     if node is None:  # everything cancelled
-        if hasattr(ast, "Constant"):
-            node = ast.Constant(op_null_with_dtype)
-        else:
-            node = ast.Num(op_null_with_dtype)
+        node = ast.Constant(op_null_with_dtype)
     if (
         hasattr(node, "dtype")
         and dtype_hierarchy[node.dtype] < dtype_hierarchy[orignode_dtype]
     ):
-        node = ast.BinOp(ast.Num(op_null_with_dtype), op_primary(), node)
+        node = ast.BinOp(ast.Constant(op_null_with_dtype), op_primary(), node)
     node.collected = True
     return node
 

brian2/parsing/bast.py

@@ -8,7 +8,6 @@
 
 import numpy
 
-from brian2.parsing.rendering import get_node_value
 from brian2.utils.logger import get_logger
 
 __all__ = ["brian_ast", "BrianASTRenderer", "dtype_hierarchy"]
@@ -168,12 +167,12 @@ def render_Name(self, node):
 
     def render_Num(self, node):
         node.complexity = 0
-        node.dtype = brian_dtype_from_value(get_node_value(node))
+        node.dtype = brian_dtype_from_value(node.value)
         node.scalar = True
         node.stateless = True
         return node
 
-    def render_Constant(self, node):  # For literals in Python 3.8
+    def render_Constant(self, node):  # For literals in Python >= 3.8
         if node.value is True or node.value is False or node.value is None:
             return self.render_NameConstant(node)
         else:

brian2/parsing/expressions.py

@@ -70,10 +70,7 @@ def is_boolean_expression(expr, variables):
             raise SyntaxError(
                 "Expression ought to be boolean but is not (e.g. 'x<y and 3')"
             )
-    elif expr.__class__ in [
-        getattr(ast, "NameConstant", None),
-        getattr(ast, "Constant", None),
-    ]:
+    elif expr.__class__ is ast.Constant:
         value = expr.value
         if value is True or value is False:
             return True
@@ -140,21 +137,8 @@ def _get_value_from_expression(expr, variables):
             return 1.0 if name == "True" else 0.0
         else:
             raise ValueError(f"Unknown identifier {name}")
-    elif expr.__class__ is getattr(ast, "NameConstant", None):
-        value = expr.value
-        if value is True or value is False:
-            return 1.0 if value else 0.0
-        else:
-            raise ValueError(f"Do not know how to deal with value {value}")
-    elif expr.__class__ is ast.Num or expr.__class__ is getattr(
-        ast, "Constant", None
-    ):  # Python 3.8
-        # In Python 3.8, boolean values are represented by Constant, not by
-        # NameConstant
-        if expr.n is True or expr.n is False:
-            return 1.0 if expr.n else 0.0
-        else:
-            return expr.n
+    elif expr.__class__ is ast.Constant:
+        return expr.value
     elif expr.__class__ is ast.BoolOp:
         raise SyntaxError(
             "Cannot determine the numerical value for a boolean operation."
@@ -231,13 +215,6 @@ def parse_expression_dimensions(expr, variables, orig_expr=None):
         orig_expr = expr
         mod = ast.parse(expr, mode="eval")
         expr = mod.body
-    if expr.__class__ is getattr(ast, "NameConstant", None):
-        # new class for True, False, None in Python 3.4
-        value = expr.value
-        if value is True or value is False:
-            return DIMENSIONLESS
-        else:
-            raise ValueError(f"Do not know how to handle value {value}")
     if expr.__class__ is ast.Name:
         name = expr.id
         # Raise an error if a function is called as if it were a variable
@@ -253,9 +230,7 @@ def parse_expression_dimensions(expr, variables, orig_expr=None):
             return DIMENSIONLESS
         else:
             raise KeyError(f"Unknown identifier {name}")
-    elif expr.__class__ is ast.Num or expr.__class__ is getattr(
-        ast, "Constant", None
-    ):  # Python 3.8
+    elif expr.__class__ is ast.Constant:
         return DIMENSIONLESS
     elif expr.__class__ is ast.BoolOp:
         # check that the units are valid in each subexpression

brian2/parsing/rendering.py

@@ -10,18 +10,9 @@
     "NumpyNodeRenderer",
     "CPPNodeRenderer",
     "SympyNodeRenderer",
-    "get_node_value",
 ]
 
 
-def get_node_value(node):
-    """Helper function to mask differences between Python versions"""
-    value = getattr(node, "n", getattr(node, "value", None))
-    if value is None:
-        raise AttributeError(f'Node {node} has neither "n" nor "value" attribute')
-    return value
-
-
 class NodeRenderer:
     expression_ops = {
         # BinOp
@@ -90,9 +81,9 @@ def render_Name(self, node):
         return node.id
 
     def render_Num(self, node):
-        return repr(get_node_value(node))
+        return repr(node.value)
 
-    def render_Constant(self, node):  # For literals in Python 3.8
+    def render_Constant(self, node):
         if node.value is True or node.value is False or node.value is None:
             return self.render_NameConstant(node)
         else:
@@ -121,11 +112,9 @@ def render_element_parentheses(self, node):
         Render an element with parentheses around it or leave them away for
         numbers, names and function calls.
         """
-        if node.__class__.__name__ in ["Name", "NameConstant"]:
+        if node.__class__.__name__ == "Name":
             return self.render_node(node)
-        elif (
-            node.__class__.__name__ in ["Num", "Constant"] and get_node_value(node) >= 0
-        ):
+        elif node.__class__.__name__ in ["Num", "Constant"] and node.value >= 0:
             return self.render_node(node)
         elif node.__class__.__name__ == "Call":
             return self.render_node(node)
@@ -278,10 +267,10 @@ def render_NameConstant(self, node):
             return str(node.value)
 
     def render_Num(self, node):
-        if isinstance(node.n, numbers.Integral):
-            return sympy.Integer(node.n)
+        if isinstance(node.value, numbers.Integral):
+            return sympy.Integer(node.value)
         else:
-            return sympy.Float(node.n)
+            return sympy.Float(node.value)
 
     def render_BinOp(self, node):
         op_name = node.op.__class__.__name__
@@ -356,7 +345,6 @@ def render_BinOp(self, node):
             return NodeRenderer.render_BinOp(self, node)
 
     def render_NameConstant(self, node):
-        # In Python 3.4, None, True and False go here
         return {True: "true", False: "false"}.get(node.value, node.value)
 
     def render_Name(self, node):