From a31a4bcd6aafb24eb984f5527b1c8f14813cac2c Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Sat, 17 Aug 2019 18:41:15 -0500
Subject: [PATCH 1/2] Replace Expression.strifier with
 Expression.make_stringifier to allow stringifiers with different constructor
 arguments

---
 pymbolic/mapper/stringifier.py | 12 ++++++------
 pymbolic/primitives.py         | 30 ++++++++++++++++++++++--------
 pymbolic/version.py            |  2 +-
 3 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/pymbolic/mapper/stringifier.py b/pymbolic/mapper/stringifier.py
index ce6f0b8..c5abb3a 100644
--- a/pymbolic/mapper/stringifier.py
+++ b/pymbolic/mapper/stringifier.py
@@ -119,13 +119,13 @@ class StringifyMapper(pymbolic.mapper.Mapper):
 
     # {{{ mappings
 
-    def handle_unsupported_expression(self, victim, enclosing_prec, *args, **kwargs):
-        strifier = victim.stringifier()
-        if isinstance(self, strifier):
+    def handle_unsupported_expression(self, expr, enclosing_prec, *args, **kwargs):
+        strifier = expr.make_stringifier(self)
+        if isinstance(self, type(strifier)):
             raise ValueError("stringifier '%s' can't handle '%s'"
-                    % (self, victim.__class__))
-        return strifier(self.constant_mapper)(
-                victim, enclosing_prec, *args, **kwargs)
+                    % (self, expr.__class__))
+        return strifier(
+                expr, enclosing_prec, *args, **kwargs)
 
     def map_constant(self, expr, enclosing_prec, *args, **kwargs):
         result = self.constant_mapper(expr)
diff --git a/pymbolic/primitives.py b/pymbolic/primitives.py
index 8bc8042..93c14fb 100644
--- a/pymbolic/primitives.py
+++ b/pymbolic/primitives.py
@@ -191,7 +191,7 @@ class Expression(object):
 
     .. method:: __getitem__
 
-    .. automethod:: stringifier
+    .. automethod:: make_stringifier
 
     .. automethod:: __eq__
     .. automethod:: __hash__
@@ -446,13 +446,27 @@ class Expression(object):
         from pymbolic.mapper.evaluator import evaluate_to_float
         return evaluate_to_float(self)
 
-    def stringifier(self):
-        """Return a :class:`pymbolic.mapper.Mapper` class used to yield
-        a human-readable representation of *self*. Usually a subclass
-        of :class:`pymbolic.mapper.stringifier.StringifyMapper`.
+    def make_stringifier(self, originating_stringifier=None):
+        """Return a :class:`pymbolic.mapper.Mapper` instance that can
+        be used to generate a human-readable representation of *self*. Usually
+        a subclass of :class:`pymbolic.mapper.stringifier.StringifyMapper`.
         """
-        from pymbolic.mapper.stringifier import StringifyMapper
-        return StringifyMapper
+        if originating_stringifier is None:
+            stringify_mapper_args = ()
+        else:
+            stringify_mapper_args = originating_stringifier.constant_mapper
+
+        try:
+            stringifier_class_getter = self.stringifier
+        except AttributeError:
+            from pymbolic.mapper.stringifier import StringifyMapper
+            return StringifyMapper(*stringify_mapper_args)
+        else:
+            from warnings import warn
+            warn("%s overrides 'stringifier', which is deprecated. "
+                    "Override 'make_stringifier' instead.")
+
+            return stringifier_class_getter()(*stringify_mapper_args)
 
     def __str__(self):
         """Use the :meth:`stringifier` to return a human-readable
@@ -460,7 +474,7 @@ class Expression(object):
         """
 
         from pymbolic.mapper.stringifier import PREC_NONE
-        return self.stringifier()()(self, PREC_NONE)
+        return self.make_stringifier()(self, PREC_NONE)
 
     def _safe_repr(self, limit=10):
         if limit <= 0:
diff --git a/pymbolic/version.py b/pymbolic/version.py
index 922dd50..6ba2863 100644
--- a/pymbolic/version.py
+++ b/pymbolic/version.py
@@ -1,3 +1,3 @@
-VERSION = (2018, 1)
+VERSION = (2019, 1)
 VERSION_STATUS = ""
 VERSION_TEXT = ".".join(str(x) for x in VERSION) + VERSION_STATUS
-- 
GitLab


From de093f0b6a4fe085904b860deb5de8999bbf5458 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Sat, 17 Aug 2019 18:46:31 -0500
Subject: [PATCH 2/2] Allow Expression.stringifier to return None to
 force-break older versions of pymbolic

---
 pymbolic/primitives.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/pymbolic/primitives.py b/pymbolic/primitives.py
index 93c14fb..fbead08 100644
--- a/pymbolic/primitives.py
+++ b/pymbolic/primitives.py
@@ -459,14 +459,17 @@ class Expression(object):
         try:
             stringifier_class_getter = self.stringifier
         except AttributeError:
-            from pymbolic.mapper.stringifier import StringifyMapper
-            return StringifyMapper(*stringify_mapper_args)
+            pass
         else:
             from warnings import warn
             warn("%s overrides 'stringifier', which is deprecated. "
                     "Override 'make_stringifier' instead.")
 
-            return stringifier_class_getter()(*stringify_mapper_args)
+            if stringifier_class_getter is not None:
+                return stringifier_class_getter()(*stringify_mapper_args)
+
+        from pymbolic.mapper.stringifier import StringifyMapper
+        return StringifyMapper(*stringify_mapper_args)
 
     def __str__(self):
         """Use the :meth:`stringifier` to return a human-readable
-- 
GitLab