From 65a269a9c44b0b1e13a3f26c67eeab33d57877be Mon Sep 17 00:00:00 2001
From: Kaushik Kulkarni <kaushikcfd@gmail.com>
Date: Sun, 22 Dec 2019 12:57:31 -0600
Subject: [PATCH 1/2] parses tuples with trailing commas correctly

---
 pymbolic/parser.py    | 6 +++++-
 test/test_pymbolic.py | 3 +--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/pymbolic/parser.py b/pymbolic/parser.py
index 85f75af..da55e1e 100644
--- a/pymbolic/parser.py
+++ b/pymbolic/parser.py
@@ -469,7 +469,11 @@ class Parser(object):
 
             pstate.advance()
             if pstate.is_at_end() or pstate.next_tag() is _closepar:
-                left_exp = (left_exp,)
+                if isinstance(left_exp, (tuple, list)) \
+                        and not isinstance(left_exp, FinalizedContainer):
+                    pass
+                else:
+                    left_exp = (left_exp,)
             else:
                 new_el = self.parse_expression(pstate, _PREC_COMMA)
                 if isinstance(left_exp, (tuple, list)) \
diff --git a/test/test_pymbolic.py b/test/test_pymbolic.py
index 2d6f3f7..e199c76 100644
--- a/test/test_pymbolic.py
+++ b/test/test_pymbolic.py
@@ -253,8 +253,6 @@ def test_parser():
     assert_parse_roundtrip("(3,)")
 
     assert_parse_roundtrip("[x + 3, 3, 5]")
-    # FIXME: trailing commas not allowed
-    # assert parse("[x + 3, 3, 5]") == parse("[x + 3, 3, 5]")
     assert_parse_roundtrip("[]")
     assert_parse_roundtrip("[x]")
 
@@ -289,6 +287,7 @@ def test_parser():
     assert_parsed_same_as_python('5+i if i>=0 else (0 if i<-1 else 10)')
     assert_parsed_same_as_python("0 if 1 if 2 else 3 else 4")
     assert_parsed_same_as_python("0 if (1 if 2 else 3) else 4")
+    assert_parsed_same_as_python("(2, 3,)")
 
     with pytest.deprecated_call():
         parse('1+if(0, 1, 2)')
-- 
GitLab


From 83bf966e5f4b52e2a76a1cc654c9471f15fe12bf Mon Sep 17 00:00:00 2001
From: Kaushik Kulkarni <kaushikcfd@gmail.com>
Date: Mon, 30 Dec 2019 18:36:54 -0600
Subject: [PATCH 2/2] explains
 https://gitlab.tiker.net/inducer/pymbolic/merge_requests/48

---
 pymbolic/parser.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pymbolic/parser.py b/pymbolic/parser.py
index da55e1e..26cabd4 100644
--- a/pymbolic/parser.py
+++ b/pymbolic/parser.py
@@ -471,6 +471,7 @@ class Parser(object):
             if pstate.is_at_end() or pstate.next_tag() is _closepar:
                 if isinstance(left_exp, (tuple, list)) \
                         and not isinstance(left_exp, FinalizedContainer):
+                    # left_expr is a container with trailing commas
                     pass
                 else:
                     left_exp = (left_exp,)
-- 
GitLab