#11565: Merge with 3.1.

1 files changed, 15 insertions, 1 deletions

diff --git a/Lib/csv.py b/Lib/csv.py
index dbe6db7ead..8dfc77e310 100644
--- a/Lib/csv.py
+++ b/Lib/csv.py
@@ -20,7 +20,7 @@ __all__ = [ "QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE",
             "unregister_dialect", "__version__", "DictReader", "DictWriter" ]
 
 class Dialect:
-    """Describe an Excel dialect.
+    """Describe a CSV dialect.
 
     This must be subclassed (see csv.excel).  Valid attributes are:
     delimiter, quotechar, escapechar, doublequote, skipinitialspace,
@@ -65,6 +65,16 @@ class excel_tab(excel):
     delimiter = '\t'
 register_dialect("excel-tab", excel_tab)
 
+class unix_dialect(Dialect):
+    """Describe the usual properties of Unix-generated CSV files."""
+    delimiter = ','
+    quotechar = '"'
+    doublequote = True
+    skipinitialspace = False
+    lineterminator = '\n'
+    quoting = QUOTE_ALL
+register_dialect("unix", unix_dialect)
+
 
 class DictReader:
     def __init__(self, f, fieldnames=None, restkey=None, restval=None,
@@ -127,6 +137,10 @@ class DictWriter:
         self.extrasaction = extrasaction
         self.writer = writer(f, dialect, *args, **kwds)
 
+    def writeheader(self):
+        header = dict(zip(self.fieldnames, self.fieldnames))
+        self.writerow(header)
+
     def _dict_to_list(self, rowdict):
         if self.extrasaction == "raise":
             wrong_fields = [k for k in rowdict if k not in self.fieldnames]