Add context-sensitive field name completion to Ada parser

This updates the Ada expression parser to implement context-sensitive
field name completion.  This is PR ada/28727.

This is somewhat complicated due to some choices in the Ada lexer --
it chooses to represent a sequence of "."-separated identifiers as a
single token, so the parser must partially recreate the completer's
logic to find the completion word boundaries.

Despite the minor warts in this patch, though, it is a decent
improvement.  It's possible that the DWARF reader rewrite will help
fix the package completion problem pointed out in this patch as well.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28727

1 files changed, 9 insertions, 1 deletions

diff --git a/gdb/expop.h b/gdb/expop.h
index c159d96a561..a17311f74e5 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -1005,10 +1005,18 @@ public:
   /* Try to complete this operation in the context of EXP.  TRACKER is
      the completion tracker to update.  Return true if completion was
      possible, false otherwise.  */
-  bool complete (struct expression *exp, completion_tracker &tracker);
+  virtual bool complete (struct expression *exp, completion_tracker &tracker)
+  {
+    return complete (exp, tracker, "");
+  }
 
 protected:
 
+  /* Do the work of the public 'complete' method.  PREFIX is prepended
+     to each result.  */
+  bool complete (struct expression *exp, completion_tracker &tracker,
+		 const char *prefix);
+
   using tuple_holding_operation::tuple_holding_operation;
 };