lalr1.cc: location.hh and position.hh are not generated without %defines

* data/location.cc (b4_position_define, b4_location_define): New.
(location.hh, position.hh): Generate only if %defines.
* data/lalr1.cc: therefore, define these classes when locations are
needed, but headers are not generated.
* tests/output.at: Check that these files are not generated.
* NEWS: Document.

NEWS

@@ -84,6 +84,11 @@ GNU Bison NEWS
 
 ** C++ skeletons improvements
 
+*** parser header (%defines) is no longer mandatory (lalr1.cc)
+
+  In which case, if needed, the support classes are defined in the generated
+  parser, instead of additional files such as position.hh and location.hh.
+
 *** locations are no longer mandatory (lalr1.cc, glr.cc)
 
   Both lalr1.cc and glr.cc no longer require %location.

TODO

@@ -7,6 +7,9 @@ show_sub_messages should call show_sub_message.
 b4_shared_declarations is no longer what it is.  Make it
 b4_parser_declaration for instance.
 
+** glr.cc: %defines
+it should not be mandatory.
+
 ** Variable names.
 What should we name `variant' and `lex_symbol'?
 

data/lalr1.cc

@@ -120,10 +120,6 @@ m4_pushdef([b4_copyright_years],
 m4_define([b4_parser_class_name],
           [b4_percent_define_get([[parser_class_name]])])
 
-# The header is mandatory.
-b4_defines_if([],
-              [b4_fatal([b4_skeleton[: using %%defines is mandatory]])])
-
 b4_locations_if([b4_percent_define_ifdef([[location_type]], [],
   [# Backward compatibility.
    m4_define([b4_location_constructors])
@@ -141,18 +137,21 @@ m4_define([b4_shared_declarations],
 # include <stdexcept>
 # include <string>
 # include <iostream>
-# include "stack.hh"
-]b4_locations_if([b4_percent_define_ifdef([[location_type]], [],
-                                          [[# include "location.hh"]])])[
-
-]b4_variant_if([b4_namespace_open
-b4_variant_define
-b4_namespace_close])[
 
 ]b4_YYDEBUG_define[
 
+# include "stack.hh"
+]b4_locations_if([b4_percent_define_ifdef([[location_type]], [],
+    [b4_defines_if([[# include "location.hh"]])])])[
+
 ]b4_namespace_open[
 
+]b4_locations_if([b4_percent_define_ifdef([[location_type]], [],
+  [b4_defines_if([], [b4_position_define
+b4_location_define])])])[
+
+]b4_variant_if([b4_variant_define])[
+
   /// A Bison parser.
   class ]b4_parser_class_name[
   {

data/location.cc

@@ -18,27 +18,11 @@
 m4_pushdef([b4_copyright_years],
            [2002-2012])
 
-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl
-@output(b4_dir_prefix[]position.hh@)@
-b4_copyright([Positions for Bison parsers in C++])[
-
-/**
- ** \file ]b4_dir_prefix[position.hh
- ** Define the ]b4_namespace_ref[::position class.
- */
-
-]b4_cpp_guard_open([b4_dir_prefix[]position.hh])[
-
-# include <algorithm> // std::max
-# include <iosfwd>
-# include <string>
-
-]b4_null_define[
-
-]b4_namespace_open[
-  /// Abstract a position.
+# b4_position_define
+# ------------------
+# Define class position.
+m4_define([b4_position_define],
+[[  /// Abstract a position.
   class position
   {
   public:
@@ -147,26 +131,13 @@ b4_copyright([Positions for Bison parsers in C++])[
       ostr << *pos.filename << ':';
     return ostr << pos.line << '.' << pos.column;
   }
+]])
 
-]b4_namespace_close[
-]b4_cpp_guard_close([b4_dir_prefix[]position.hh])
-@output(b4_dir_prefix[]location.hh@)@
-b4_copyright([Locations for Bison parsers in C++])[
 
-/**
- ** \file ]b4_dir_prefix[location.hh
- ** Define the ]b4_namespace_ref[::location class.
- */
-
-]b4_cpp_guard_open([b4_dir_prefix[]location.hh])[
-
-# include <iostream>
-# include <string>
-# include "position.hh"
-
-]b4_namespace_open[
-
-  /// Abstract a location.
+# b4_location_define
+# ------------------
+m4_define([b4_location_define],
+[[  /// Abstract a location.
   class location
   {
   public:
@@ -291,10 +262,52 @@ b4_copyright([Locations for Bison parsers in C++])[
       ostr << '-' << last.column;
     return ostr;
   }
+]])
 
+
+# We do want M4 expansion after # for CPP macros.
+m4_changecom()
+b4_defines_if([
+m4_divert_push(0)dnl
+@output(b4_dir_prefix[]position.hh@)@
+b4_copyright([Positions for Bison parsers in C++])[
+
+/**
+ ** \file ]b4_dir_prefix[position.hh
+ ** Define the ]b4_namespace_ref[::position class.
+ */
+
+]b4_cpp_guard_open([b4_dir_prefix[]position.hh])[
+
+# include <algorithm> // std::max
+# include <iosfwd>
+# include <string>
+
+]b4_null_define[
+
+]b4_namespace_open[
+]b4_position_define[
 ]b4_namespace_close[
+]b4_cpp_guard_close([b4_dir_prefix[]position.hh])
+@output(b4_dir_prefix[]location.hh@)@
+b4_copyright([Locations for Bison parsers in C++])[
 
+/**
+ ** \file ]b4_dir_prefix[location.hh
+ ** Define the ]b4_namespace_ref[::location class.
+ */
+
+]b4_cpp_guard_open([b4_dir_prefix[]location.hh])[
+
+# include <iostream>
+# include <string>
+# include "position.hh"
+
+]b4_namespace_open[
+]b4_location_define[
+]b4_namespace_close[
 ]b4_cpp_guard_close([b4_dir_prefix[]location.hh])
 m4_divert_pop(0)
+])# b4_defines_if
 m4_popdef([b4_copyright_years])dnl
 m4_changecom([#])

tests/output.at

@@ -113,9 +113,15 @@ AT_CHECK([grep 'include .subdir/' $1.cc], 1, [])
 AT_CHECK([grep 'include .subdir/' $1.hh], 1, [])
 ])
 
+AT_CHECK_OUTPUT([foo.yy], [%skeleton "lalr1.cc" %verbose], [],
+                [foo.tab.cc foo.output stack.hh])
+
 AT_CHECK_OUTPUT([foo.yy], [%skeleton "lalr1.cc" %defines %verbose], [],
                 [foo.tab.cc foo.tab.hh foo.output stack.hh])
 
+AT_CHECK_OUTPUT([foo.yy], [%skeleton "lalr1.cc" %verbose %locations], [],
+                [foo.tab.cc foo.output stack.hh])
+
 AT_CHECK_OUTPUT([foo.yy], [%skeleton "lalr1.cc" %defines %verbose %locations], [],
                 [foo.tab.cc foo.tab.hh foo.output location.hh stack.hh position.hh])