[PATCH 1/2] libstdc++: Count pretty-printed tuple elements from 0 not 1

[Paul Smith <psmith@gnu.org>]

Show 0-based offsets for std::tuple members, to match with std::get.

libstdc++-v3/ChangeLog:

        * python/libstdcxx/v6/printers.py (StdTuplePrinter): don't increment
        self.count until after generating the result string.
---
 libstdc++-v3/python/libstdcxx/v6/printers.py | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/libstdc++-v3/python/libstdcxx/v6/printers.py b/libstdc++-v3/python/libstdcxx/v6/printers.py
index 550e0ecdd22..14a6d998690 100644
--- a/libstdc++-v3/python/libstdcxx/v6/printers.py
+++ b/libstdc++-v3/python/libstdcxx/v6/printers.py
@@ -560,16 +560,17 @@ class StdTuplePrinter:
                 # Process left node and set it as head.
                 self.head  = self.head.cast (nodes[0].type)

-            self.count = self.count + 1
-
             # Finally, check the implementation.  If it is
             # wrapped in _M_head_impl return that, otherwise return
             # the value "as is".
             fields = impl.type.fields ()
-            if len (fields) < 1 or fields[0].name != "_M_head_impl":
-                return ('[%d]' % self.count, impl)
-            else:
-                return ('[%d]' % self.count, impl['_M_head_impl'])
+            if len (fields) > 0 and fields[0].name == "_M_head_impl":
+                impl = impl['_M_head_impl']
+
+            out = '[%d]' % self.count
+            self.count = self.count + 1
+
+            return (out, impl)

     def __init__ (self, typename, val):
         self.typename = strip_versioned_namespace(typename)
--
2.28.0