round-trip sequence key elements0.12.14

8 files changed, 102 insertions, 13 deletions

diff --git a/README.rst b/README.rst
index 4203014..5418ead 100644
--- a/README.rst
+++ b/README.rst
@@ -18,6 +18,10 @@ ChangeLog
 
 ::
 
+  0.12.14 (2016-09-21):
+   - preserve round-trip sequences that are mapping keys 
+     (prompted by stackoverflow question 39595807 from Nowox)
+
   0.12.13 (2016-09-15):
    - Fix for issue #60 representation of CommentedMap with merge
      keys incorrect (reported by Tal Liron)
diff --git a/__init__.py b/__init__.py
index 15b8eff..15142b6 100644
--- a/__init__.py
+++ b/__init__.py
@@ -9,7 +9,7 @@ from __future__ import absolute_import
 
 _package_data = dict(
     full_package_name="ruamel.yaml",
-    version_info=(0, 12, 13),
+    version_info=(0, 12, 14),
     author="Anthon van der Neut",
     author_email="a.van.der.neut@ruamel.eu",
     description="ruamel.yaml is a YAML parser/emitter that supports roundtrip preservation of comments, seq/map flow style, and map key order",  # NOQA
diff --git a/_test/roundtrip.py b/_test/roundtrip.py
index 632c206..cd79f2c 100644
--- a/_test/roundtrip.py
+++ b/_test/roundtrip.py
@@ -28,18 +28,19 @@ def round_trip_load(inp, preserve_quotes=None):
 
 
 def round_trip_dump(data, indent=None, block_seq_indent=None, top_level_colon_align=None,
-                    prefix_colon=None, explicit_start=None, explicit_end=None):
+                    prefix_colon=None, explicit_start=None, explicit_end=None, version=None):
     return ruamel.yaml.round_trip_dump(data,
                                        indent=indent, block_seq_indent=block_seq_indent,
                                        top_level_colon_align=top_level_colon_align,
                                        prefix_colon=prefix_colon,
                                        explicit_start=explicit_start,
-                                       explicit_end=explicit_end)
+                                       explicit_end=explicit_end,
+                                       version=version)
 
 
 def round_trip(inp, outp=None, extra=None, intermediate=None, indent=None,
                block_seq_indent=None, top_level_colon_align=None, prefix_colon=None,
-               preserve_quotes=None):
+               preserve_quotes=None, explicit_start=None, version=None):
     """
     inp:    input string to parse
     outp:   expected output (equals input if not specified)
@@ -58,11 +59,13 @@ def round_trip(inp, outp=None, extra=None, intermediate=None, indent=None,
                     raise ValueError
     res = round_trip_dump(data, indent=indent, block_seq_indent=block_seq_indent,
                           top_level_colon_align=top_level_colon_align,
-                          prefix_colon=prefix_colon)
+                          prefix_colon=prefix_colon, explicit_start=explicit_start,
+                          version=version)
     print('roundtrip data:\n', res, sep='')
     assert res == doutp
     res = round_trip_dump(data, indent=indent, block_seq_indent=block_seq_indent,
                           top_level_colon_align=top_level_colon_align,
-                          prefix_colon=prefix_colon)
+                          prefix_colon=prefix_colon, explicit_start=explicit_start,
+                          version=version)
     print('roundtrip second round data:\n', res, sep='')
     assert res == doutp
diff --git a/_test/test_flowsequencekey.py b/_test/test_flowsequencekey.py
new file mode 100644
index 0000000..6f6d7db
--- /dev/null
+++ b/_test/test_flowsequencekey.py
@@ -0,0 +1,25 @@
+# coding: utf-8
+
+"""
+test flow style sequences as keys roundtrip
+
+"""
+
+# import pytest
+# import ruamel.yaml
+
+from roundtrip import round_trip  # , dedent, round_trip_load, round_trip_dump
+
+
+class TestFlowStyleSequenceKey:
+    def test_so_39595807(self):
+        round_trip("""
+        %YAML 1.2
+        ---
+        [2, 3, 4]:
+          a:
+          - 1
+          - 2
+          b: Hello World!
+          c: 'Voilà!'
+        """, preserve_quotes=True, explicit_start=True, version=(1, 2))
diff --git a/comments.py b/comments.py
index 7dd8e8e..34154e8 100644
--- a/comments.py
+++ b/comments.py
@@ -12,7 +12,8 @@ from collections import MutableSet, Sized, Set  # type: ignore
 
 from ruamel.yaml.compat import ordereddict, PY2
 
-__all__ = ["CommentedSeq", "CommentedMap", "CommentedOrderedMap",
+__all__ = ["CommentedSeq", "CommentedKeySeq",
+           "CommentedMap", "CommentedOrderedMap",
            "CommentedSet", 'comment_attrib', 'merge_attrib']
 
 comment_attrib = '_yaml_comment'
@@ -321,8 +322,50 @@ class CommentedSeq(list, CommentedBase):
         return pre_comments
 
 
-class CommentedMapView(Sized):
+class CommentedKeySeq(tuple, CommentedBase):
+    """This primarily exists to be able to roundtrip keys that are sequences"""
+    def _yaml_add_comment(self, comment, key=NoComment):
+        if key is not NoComment:
+            self.yaml_key_comment_extend(key, comment)
+        else:
+            self.ca.comment = comment
+
+    def _yaml_add_eol_comment(self, comment, key):
+        self._yaml_add_comment(comment, key=key)
+
+    def _yaml_get_columnX(self, key):
+        return self.ca.items[key][0].start_mark.column
+
+    def _yaml_get_column(self, key):
+        column = None
+        sel_idx = None
+        pre, post = key-1, key+1
+        if pre in self.ca.items:
+            sel_idx = pre
+        elif post in self.ca.items:
+            sel_idx = post
+        else:
+            # self.ca.items is not ordered
+            for row_idx, k1 in enumerate(self):
+                if row_idx >= key:
+                    break
+                if row_idx not in self.ca.items:
+                    continue
+                sel_idx = row_idx
+        if sel_idx is not None:
+            column = self._yaml_get_columnX(sel_idx)
+        return column
 
+    def _yaml_get_pre_comment(self):
+        if self.ca.comment is None:
+            pre_comments = []
+            self.ca.comment = [None, pre_comments]
+        else:
+            pre_comments = self.ca.comment[1] = []
+        return pre_comments
+
+
+class CommentedMapView(Sized):
     __slots__ = '_mapping',
 
     def __init__(self, mapping):
diff --git a/constructor.py b/constructor.py
index f2a6cc3..03c88ae 100644
--- a/constructor.py
+++ b/constructor.py
@@ -956,7 +956,12 @@ class RoundTripConstructor(SafeConstructor):
             # lists are not hashable, but tuples are
             if not isinstance(key, collections.Hashable):
                 if isinstance(key, list):
-                    key = tuple(key)
+                    key = CommentedKeySeq(key)
+                    if key_node.flow_style is True:
+                        key.fa.set_flow_style()
+                    elif key_node.flow_style is False:
+                        key.fa.set_block_style()
+                    # key = tuple(key)
             if PY2:
                 try:
                     hash(key)
diff --git a/emitter.py b/emitter.py
index ac88dc6..497f173 100644
--- a/emitter.py
+++ b/emitter.py
@@ -465,8 +465,9 @@ class Emitter(object):
                 self.write_pre_comment(self.event)
             self.write_indent()
             if self.check_simple_key():
-                if self.event.style == '?':
-                    self.write_indicator(u'?', True, indention=True)
+                if not isinstance(self.event, SequenceStartEvent):  # sequence keys
+                    if self.event.style == '?':
+                        self.write_indicator(u'?', True, indention=True)
                 self.states.append(self.expect_block_mapping_simple_value)
                 self.expect_node(mapping=True, simple_key=True)
             else:
@@ -526,6 +527,8 @@ class Emitter(object):
             length += len(self.analysis.scalar)
         return (length < self.MAX_SIMPLE_KEY_LENGTH and (
             isinstance(self.event, AliasEvent) or
+            (isinstance(self.event, SequenceStartEvent) and
+             self.event.flow_style is True) or
             (isinstance(self.event, ScalarEvent) and
              not self.analysis.empty and not self.analysis.multiline) or
             self.check_empty_sequence() or self.check_empty_mapping()))
diff --git a/representer.py b/representer.py
index 3e67a96..8fcbc7c 100644
--- a/representer.py
+++ b/representer.py
@@ -576,8 +576,8 @@ Representer.add_multi_representer(object,
                                   Representer.represent_object)
 
 
-from ruamel.yaml.comments import CommentedMap, CommentedOrderedMap, \
-    CommentedSeq, CommentedSet, comment_attrib, merge_attrib    # NOQA
+from ruamel.yaml.comments import CommentedMap, CommentedOrderedMap, CommentedSeq, \
+    CommentedKeySeq, CommentedSet, comment_attrib, merge_attrib    # NOQA
 
 
 class RoundTripRepresenter(SafeRepresenter):
@@ -658,6 +658,12 @@ class RoundTripRepresenter(SafeRepresenter):
                 node.flow_style = best_style
         return node
 
+    def represent_key(self, data):
+        if isinstance(data, CommentedKeySeq):
+            return self.represent_sequence(u'tag:yaml.org,2002:seq', data,
+                                           flow_style=True)
+        return SafeRepresenter.represent_key(self, data)
+
     def represent_mapping(self, tag, mapping, flow_style=None):
         value = []
         try: