gh-67230: add quoting rules to csv module (GH-29469)

Add two quoting styles for csv dialects.
They will help to work with certain databases in particular.

Automerge-Triggered-By: GH:merwok

1 files changed, 15 insertions, 1 deletions

diff --git a/Modules/_csv.c b/Modules/_csv.c
index bd33708..2217cc2 100644
--- a/Modules/_csv.c
+++ b/Modules/_csv.c
@@ -82,7 +82,8 @@ typedef enum {
 } ParserState;
 
 typedef enum {
-    QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE
+    QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE,
+    QUOTE_STRINGS, QUOTE_NOTNULL
 } QuoteStyle;
 
 typedef struct {
@@ -95,6 +96,8 @@ static const StyleDesc quote_styles[] = {
     { QUOTE_ALL,        "QUOTE_ALL" },
     { QUOTE_NONNUMERIC, "QUOTE_NONNUMERIC" },
     { QUOTE_NONE,       "QUOTE_NONE" },
+    { QUOTE_STRINGS,    "QUOTE_STRINGS" },
+    { QUOTE_NOTNULL,    "QUOTE_NOTNULL" },
     { 0 }
 };
 
@@ -1264,6 +1267,12 @@ csv_writerow(WriterObj *self, PyObject *seq)
         case QUOTE_ALL:
             quoted = 1;
             break;
+        case QUOTE_STRINGS:
+            quoted = PyUnicode_Check(field);
+            break;
+        case QUOTE_NOTNULL:
+            quoted = field != Py_None;
+            break;
         default:
             quoted = 0;
             break;
@@ -1659,6 +1668,11 @@ PyDoc_STRVAR(csv_module_doc,
 "        csv.QUOTE_NONNUMERIC means that quotes are always placed around\n"
 "            fields which do not parse as integers or floating point\n"
 "            numbers.\n"
+"        csv.QUOTE_STRINGS means that quotes are always placed around\n"
+"            fields which are strings.  Note that the Python value None\n"
+"            is not a string.\n"
+"        csv.QUOTE_NOTNULL means that quotes are only placed around fields\n"
+"            that are not the Python value None.\n"
 "        csv.QUOTE_NONE means that quotes are never placed around fields.\n"
 "    * escapechar - specifies a one-character string used to escape\n"
 "        the delimiter when quoting is set to QUOTE_NONE.\n"