Bug 1434998 - Allow for REPLACE values to be Patterns or PatternElements

fluent/migrate/transforms.py

@@ -64,6 +64,7 @@
 """
 
 from __future__ import unicode_literals
+import itertools
 
 import fluent.syntax.ast as FTL
 from .errors import NotSupportedError
@@ -128,11 +129,11 @@ def __call__(self, ctx):
 
 
 class REPLACE_IN_TEXT(Transform):
-    """Replace various placeables in the translation with FTL placeables.
+    """Replace various placeables in the translation with FTL.
 
     The original placeables are defined as keys on the `replacements` dict.
-    For each key the value is defined as a list of FTL Expressions to be
-    interpolated.
+    For each key the value is defined as a FTL Pattern, Placeable,
+    TextElement or Expressions to be interpolated.
     """
 
     def __init__(self, value, replacements):
@@ -141,7 +142,7 @@ def __init__(self, value, replacements):
 
     def __call__(self, ctx):
 
-        # Only replace placeable which are present in the translation.
+        # Only replace placeables which are present in the translation.
         replacements = {
             key: evaluate(ctx, repl)
             for key, repl in self.replacements.iteritems()
@@ -154,40 +155,43 @@ def __call__(self, ctx):
             lambda x, y: self.value.find(x) - self.value.find(y)
         )
 
-        # Used to reduce the `keys_in_order` list.
-        def replace(acc, cur):
-            """Convert original placeables and text into FTL Nodes.
-
-            For each original placeable the translation will be partitioned
-            around it and the text before it will be converted into an
-            `FTL.TextElement` and the placeable will be replaced with its
-            replacement. The text following the placebale will be fed again to
-            the `replace` function.
-            """
-
-            parts, rest = acc
-            before, key, after = rest.value.partition(cur)
-
-            placeable = FTL.Placeable(replacements[key])
-
-            # Return the elements found and converted so far, and the remaining
-            # text which hasn't been scanned for placeables yet.
-            return (
-                parts + [FTL.TextElement(before), placeable],
-                FTL.TextElement(after)
-            )
-
-        def is_non_empty(elem):
-            """Used for filtering empty `FTL.TextElement` nodes out."""
-            return not isinstance(elem, FTL.TextElement) or len(elem.value)
-
-        # Start with an empty list of elements and the original translation.
-        init = ([], FTL.TextElement(self.value))
-        parts, tail = reduce(replace, keys_in_order, init)
-
-        # Explicitly concat the trailing part to get the full list of elements
-        # and filter out the empty ones.
-        elements = filter(is_non_empty, parts + [tail])
+        # A list of PatternElements built from the legacy translation and the
+        # FTL replacements. It may contain empty or adjacent TextElements.
+        parts = []
+        tail = self.value
+
+        # Convert original placeables and text into FTL Nodes. For each
+        # original placeable the translation will be partitioned around it and
+        # the text before it will be converted into an `FTL.TextElement` and
+        # the placeable will be replaced with its replacement.
+        for key in keys_in_order:
+            before, key, tail = tail.partition(key)
+
+            # The replacement value can be of different types.
+            replacement = replacements[key]
+            if isinstance(replacement, FTL.Pattern):
+                repl_elements = replacement.elements
+            elif isinstance(replacement, FTL.PatternElement):
+                repl_elements = [replacement]
+            elif isinstance(replacement, FTL.Expression):
+                repl_elements = [FTL.Placeable(replacement)]
+
+            parts.append(FTL.TextElement(before))
+            parts.extend(repl_elements)
+
+        # Dont' forget about the tail after the loop ends.
+        parts.append(FTL.TextElement(tail))
+
+        # Join adjacent TextElements.
+        elements = []
+        for elem_type, elems in itertools.groupby(parts, key=type):
+            if elem_type is FTL.TextElement:
+                text = FTL.TextElement(''.join(elem.value for elem in elems))
+                # And remove empty ones.
+                if len(text.value) > 0:
+                    elements.append(text)
+            else:
+                elements.extend(elems)
 
         return FTL.Pattern(elements)
 

fluent/syntax/ast.py

@@ -190,12 +190,15 @@ def __init__(self, elements, **kwargs):
         super(Pattern, self).__init__(**kwargs)
         self.elements = elements
 
-class TextElement(SyntaxNode):
+class PatternElement(SyntaxNode):
+    pass
+
+class TextElement(PatternElement):
     def __init__(self, value, **kwargs):
         super(TextElement, self).__init__(**kwargs)
         self.value = value
 
-class Placeable(SyntaxNode):
+class Placeable(PatternElement):
     def __init__(self, expression, **kwargs):
         super(Placeable, self).__init__(**kwargs)
         self.expression = expression

tests/migrate/test_concat.py

@@ -15,6 +15,8 @@
 
 
 class MockContext(unittest.TestCase):
+    maxDiff = None
+
     def get_source(self, path, key):
         # Ignore path (test.properties) and get translations from self.strings
         # defined in setUp.

tests/migrate/test_replace.py

@@ -15,6 +15,8 @@
 
 
 class MockContext(unittest.TestCase):
+    maxDiff = None
+
     def get_source(self, path, key):
         # Ignore path (test.properties) and get translations from self.strings
         # defined in setUp.
@@ -148,6 +150,72 @@ def test_replace_last(self):
             ''')
         )
 
+    def test_replace_with_placeable(self):
+        msg = FTL.Message(
+            FTL.Identifier(u'hello'),
+            value=REPLACE(
+                'test.properties',
+                'hello',
+                {
+                    '#1': FTL.Placeable(
+                        EXTERNAL_ARGUMENT('user')
+                    )
+                }
+            )
+        )
+
+        self.assertEqual(
+            evaluate(self, msg).to_json(),
+            ftl_message_to_json('''
+                hello = Hello, { $user }!
+            ''')
+        )
+
+    def test_replace_with_text_element(self):
+        msg = FTL.Message(
+            FTL.Identifier(u'hello'),
+            value=REPLACE(
+                'test.properties',
+                'hello',
+                {
+                    '#1': FTL.TextElement('you')
+                }
+            )
+        )
+
+        self.assertEqual(
+            evaluate(self, msg).to_json(),
+            ftl_message_to_json('''
+                hello = Hello, you!
+            ''')
+        )
+
+    def test_replace_with_pattern(self):
+        msg = FTL.Message(
+            FTL.Identifier(u'hello'),
+            value=REPLACE(
+                'test.properties',
+                'hello',
+                {
+                    '#1': FTL.Pattern(
+                        elements=[
+                            FTL.TextElement('<img> '),
+                            FTL.Placeable(
+                                EXTERNAL_ARGUMENT('user')
+                            )
+                        ]
+                    )
+                }
+            )
+        )
+
+        self.assertEqual(
+            evaluate(self, msg).to_json(),
+            ftl_message_to_json('''
+                hello = Hello, <img> { $user }!
+            ''')
+        )
+
 
 if __name__ == '__main__':
     unittest.main()