pymbolic/interop/matchpy/mapper.py

+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+    from pymbolic.interop.matchpy import PymbolicOp
+
+
+class Mapper:
+    def __init__(self) -> None:
+        self.cache: dict[PymbolicOp, Any] = {}
+
+    def rec(self, expr: PymbolicOp) -> Any:
+        if expr in self.cache:
+            return self.cache[expr]
+
+        method: Callable[[PymbolicOp], Any] = getattr(self, expr._mapper_method)
+
+        return method(expr)
+
+    __call__ = rec

pymbolic/mapper/analysis.py

+from __future__ import annotations
+
+
+__copyright__ = """Copyright (C) 2022 University of Illinois Board of Trustees"""
+
+__license__ = """
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+"""
+
+
+from pymbolic.mapper import CachedWalkMapper
+
+
+__doc__ = """
+.. autoclass:: NodeCountMapper
+.. autofunction:: get_num_nodes
+"""
+
+
+# {{{ NodeCountMapper
+
+class NodeCountMapper(CachedWalkMapper):
+    """
+    Counts the number of nodes in an expression tree. Nodes that occur
+    repeatedly as well as :class:`~pymbolic.primitives.CommonSubexpression`
+    nodes are only counted once.
+
+    .. attribute:: count
+
+       The number of nodes.
+    """
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.count = 0
+
+    def post_visit(self, expr) -> None:
+        self.count += 1
+
+
+def get_num_nodes(expr) -> int:
+    """Returns the number of nodes in *expr*. Nodes that occur
+    repeatedly as well as :class:`~pymbolic.primitives.CommonSubexpression`
+    nodes are only counted once."""
+
+    ncm = NodeCountMapper()
+    ncm(expr)
+
+    return ncm.count
+
+# }}}