Add Template / Interpolation formatting to pprint

Author: loic-simon

Lib/pprint.py

@@ -566,6 +566,29 @@ def _pprint_user_string(self, object, stream, indent, allowance, context, level)
 
     _dispatch[_collections.UserString.__repr__] = _pprint_user_string
 
+    def _pprint_template(self, object, stream, indent, allowance, context, level):
+        cls_name = object.__class__.__name__
+        indent += len(cls_name) + 1
+        items = (("strings", object.strings),
+                 ("interpolations", object.interpolations))
+        stream.write(cls_name + '(')
+        self._format_namespace_items(items, stream, indent, allowance, context, level)
+        stream.write(')')
+
+    def _pprint_interpolation(self, object, stream, indent, allowance, context, level):
+        cls_name = object.__class__.__name__
+        indent += len(cls_name)
+        items = (object.value, object.expression,
+                object.conversion, object.format_spec)
+        stream.write(cls_name + '(')
+        self._format_items(items, stream, indent, allowance, context, level)
+        stream.write(')')
+
+    t = t"{0}"
+    _dispatch[type(t).__repr__] = _pprint_template
+    _dispatch[type(t.interpolations[0]).__repr__] = _pprint_interpolation
+    del t
+
     def _safe_repr(self, object, context, maxlevels, level):
         # Return triple (repr_string, isreadable, isrecursive).
         typ = type(object)

Lib/test/test_pprint.py

@@ -1130,6 +1130,38 @@ def test_user_string(self):
     'jumped over a '
     'lazy dog'}""")
 
+    def test_template(self):
+        d = t""
+        self.assertEqual(pprint.pformat(d),
+                         "Template(strings=('',), interpolations=())")
+        self.assertEqual(pprint.pformat(d), repr(d))
+        self.assertEqual(pprint.pformat(d, width=1),
+"""\
+Template(strings=('',),
+         interpolations=())""")
+        name = "World"
+        d = t"Hello {name}"
+        self.assertEqual(pprint.pformat(d),
+"""\
+Template(strings=('Hello ', ''),
+         interpolations=(Interpolation('World', 'name', None, ''),))""")
+        ver = {3.13: False, 3.14: True}
+        d = t"Hello { {"name": "Python", "version": ver}!s:z}!"
+        self.assertEqual(pprint.pformat(d, width=1),
+"""\
+Template(strings=('Hello ',
+                  '!'),
+         interpolations=(Interpolation({'name': 'Python',
+                                        'version': {3.13: False,
+                                                    3.14: True}},
+                                       ' '
+                                       '{"name": '
+                                       '"Python", '
+                                       '"version": '
+                                       'ver}',
+                                       's',
+                                       'z'),))""")
+
 
 class DottedPrettyPrinter(pprint.PrettyPrinter):