From cfec28d13ce191506fcdc49321cb30b6cecd342d Mon Sep 17 00:00:00 2001
From: Vladimir Iakovlev <nvbn.rm@gmail.com>
Date: Wed, 10 May 2017 16:09:08 +0200
Subject: [PATCH 1/3] #18: Fix formatted string with only one value, like
 `f{foo}`

---
 lib/astunparse/unparser.py | 13 +++++--------
 tests/common.py            |  3 +++
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/astunparse/unparser.py b/lib/astunparse/unparser.py
index 71a9456..c52ee87 100644
--- a/lib/astunparse/unparser.py
+++ b/lib/astunparse/unparser.py
@@ -446,7 +446,7 @@ def _Str(self, tree):
 
     def _FormattedValue(self, t):
         # FormattedValue(expr value, int? conversion, expr? format_spec)
-        self.write("{")
+        self.write("f'''{")
         self.dispatch(t.value)
         if t.conversion is not None and t.conversion != -1:
             self.write("!")
@@ -458,17 +458,14 @@ def _FormattedValue(self, t):
                 self.write(t.format_spec.s)
             else:
                 self.dispatch(t.format_spec)
-        self.write("}")
+        self.write("}'''")
 
     def _JoinedStr(self, t):
         # JoinedStr(expr* values)
-        self.write("f'''")
+        self.write("(")
         for value in t.values:
-            if isinstance(value, ast.Str):
-                self.write(value.s)
-            else:
-                self.dispatch(value)
-        self.write("'''")
+            self.dispatch(value)
+        self.write(")")
 
     def _Name(self, t):
         self.write(t.id)
diff --git a/tests/common.py b/tests/common.py
index f930308..6b0ebe7 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -288,6 +288,9 @@ def test_raise_from(self):
     def test_bytes(self):
         self.check_roundtrip("b'123'")
 
+    def test_formatted_value(self):
+        self.check_roundtrip('f"{key}"')
+
     @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
     def test_joined_str(self):
         self.check_roundtrip('f"{key}={value!s}"')

From 8de282f7c0be8107aff37d77ce45541e3a23f4ce Mon Sep 17 00:00:00 2001
From: Vladimir Iakovlev <nvbn.rm@gmail.com>
Date: Wed, 10 May 2017 17:04:29 +0200
Subject: [PATCH 2/3] #18: Handle `FormattedValue` inside `JoinedStr` and
 outside differently

---
 lib/astunparse/unparser.py | 24 +++++++++++++++++-------
 tests/common.py            |  6 +++++-
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/lib/astunparse/unparser.py b/lib/astunparse/unparser.py
index c52ee87..3db9b0b 100644
--- a/lib/astunparse/unparser.py
+++ b/lib/astunparse/unparser.py
@@ -444,9 +444,8 @@ def _Str(self, tree):
 
     format_conversions = {97: 'a', 114: 'r', 115: 's'}
 
-    def _FormattedValue(self, t):
-        # FormattedValue(expr value, int? conversion, expr? format_spec)
-        self.write("f'''{")
+    def _generic_FormattedValue(self, t):
+        self.write("{")
         self.dispatch(t.value)
         if t.conversion is not None and t.conversion != -1:
             self.write("!")
@@ -458,14 +457,25 @@ def _FormattedValue(self, t):
                 self.write(t.format_spec.s)
             else:
                 self.dispatch(t.format_spec)
-        self.write("}'''")
+        self.write("}")
+
+    def _FormattedValue(self, t):
+        # FormattedValue(expr value, int? conversion, expr? format_spec)
+        self.write("f'''")
+        self._generic_FormattedValue(t)
+        self.write("'''")
 
     def _JoinedStr(self, t):
         # JoinedStr(expr* values)
-        self.write("(")
+        self.write("f'''")
         for value in t.values:
-            self.dispatch(value)
-        self.write(")")
+            if isinstance(value, ast.Str):
+                self.write(value.s)
+            elif isinstance(value, ast.FormattedValue):
+                self._generic_FormattedValue(value)
+            else:
+                self.dispatch(value)
+        self.write("'''")
 
     def _Name(self, t):
         self.write(t.id)
diff --git a/tests/common.py b/tests/common.py
index 6b0ebe7..baeba34 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -288,8 +288,12 @@ def test_raise_from(self):
     def test_bytes(self):
         self.check_roundtrip("b'123'")
 
+    @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
     def test_formatted_value(self):
-        self.check_roundtrip('f"{key}"')
+        self.check_roundtrip('f"{value}"')
+        self.check_roundtrip('f"{value!s}"')
+        self.check_roundtrip('f"{value:4}"')
+        self.check_roundtrip('f"{value!s:4}"')
 
     @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
     def test_joined_str(self):

From 11392ea1fd0f9d73e32ab2ab1200af8c0a3120c5 Mon Sep 17 00:00:00 2001
From: Vladimir Iakovlev <nvbn.rm@gmail.com>
Date: Wed, 10 May 2017 17:39:05 +0200
Subject: [PATCH 3/3] #18: Fix `FormattedValue` on Python 3.6.1

---
 lib/astunparse/unparser.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/astunparse/unparser.py b/lib/astunparse/unparser.py
index 3db9b0b..87cc866 100644
--- a/lib/astunparse/unparser.py
+++ b/lib/astunparse/unparser.py
@@ -454,7 +454,15 @@ def _generic_FormattedValue(self, t):
         if t.format_spec is not None:
             self.write(":")
             if isinstance(t.format_spec, ast.Str):
+                # It's ast.Str in 3.6.0
                 self.write(t.format_spec.s)
+            elif isinstance(t.format_spec, ast.JoinedStr):
+                # It's ast.JoinedStr in 3.6.1+
+                for value in t.format_spec.values:
+                    if isinstance(value, ast.Str):
+                        self.write(value.s)
+                    else:
+                        self.dispatch(value)
             else:
                 self.dispatch(t.format_spec)
         self.write("}")