Add c-exp.h and c_string_operation

This adds the new file c-exp.h, where C operation classes will be
declared.  The first such class, c_string_operation, is also added
here.

gdb/ChangeLog
2021-03-08  Tom Tromey  <tom@tromey.com>

	* c-lang.c (c_string_operation::evaluate): New method.
	* c-exp.h: New file.

1 files changed, 46 insertions, 0 deletions

diff --git a/gdb/c-exp.h b/gdb/c-exp.h
new file mode 100644
index 0000000..5558a77
--- /dev/null
+++ b/gdb/c-exp.h
@@ -0,0 +1,46 @@
+/* Definitions for C expressions
+
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef C_EXP_H
+#define C_EXP_H
+
+#include "expop.h"
+
+namespace expr
+{
+
+class c_string_operation
+  : public tuple_holding_operation<enum c_string_type_values,
+				   std::vector<std::string>>
+{
+public:
+
+  using tuple_holding_operation::tuple_holding_operation;
+
+  value *evaluate (struct type *expect_type,
+		   struct expression *exp,
+		   enum noside noside) override;
+
+  enum exp_opcode opcode () const override
+  { return OP_STRING; }
+};
+
+}/* namespace expr */
+
+#endif /* C_EXP_H */