collecting some formatting & diagnostics utils here...

src/lib/format.hpp

@@ -0,0 +1,96 @@
+/*
+  FORMAT.hpp  -  helpers for formatting and diagnostics
+ 
+  Copyright (C)         Lumiera.org
+    2009,               Hermann Vosseler <Ichthyostega@web.de>
+ 
+  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 2 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, write to the Free Software
+  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ 
+*/
+
+
+/** @file format.hpp
+ ** Collection of small helpers and convenience shortcuts for diagnostics & formatting.
+ ** 
+ ** @todo we could add a facade to boost::format here, see Ticket #166
+ ** 
+ */
+
+
+#ifndef UTIL_FORMAT_H
+#define UTIL_FORMAT_H
+
+//#include "lib/util.hpp"
+#include "lib/meta/trait.hpp"
+#include "include/symbol.hpp"
+
+#include <string>
+#include <cstring>
+#include <typeinfo>
+#include <boost/utility/enable_if.hpp>
+
+
+
+namespace util {
+  
+  using lumiera::typelist::can_ToString;
+  using lumiera::Symbol;
+  using boost::enable_if;
+  using boost::disable_if;
+  using std::string;
+  
+  
+  namespace { // we need to guard the string conversion
+             //  to avoid a compiler error in case the type isn't convertible....
+    
+    template<typename X>
+    inline string
+    invoke_2string (     typename enable_if< can_ToString<X>,
+                    X >::type const& val)
+    {
+      return string(val);
+    }
+    
+    template<typename X>
+    inline string
+    invoke_2string (     typename disable_if< can_ToString<X>,
+                    X >::type const&)
+    {
+      return "";
+    }
+  }
+  
+  
+  
+  /** try to get an object converted to string */
+  template<typename TY>
+  inline string
+  str ( TY const& val
+      , Symbol prefix=""      ///< prefix to prepend in case conversion is possible
+      , Symbol fallback =0   /// < replacement text to show if string conversion fails
+      )
+    {
+      if (can_ToString<TY>::value)
+        return string(prefix) + invoke_2string<TY>(val);
+      
+      else
+        return fallback? fallback
+                       : string("«")+typeid(val).name()+"»";
+    }
+  
+  
+} // namespace util
+
+#endif /*UTIL_FORMAT_H*/

src/lib/meta/trait.hpp

@@ -0,0 +1,51 @@
+/*
+  TRAIT.hpp  -  type handling and type detection helpers
+ 
+  Copyright (C)         Lumiera.org
+    2009,               Hermann Vosseler <Ichthyostega@web.de>
+ 
+  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 2 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, write to the Free Software
+  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ 
+*/
+
+
+#ifndef LUMIERA_META_TRAIT_H
+#define LUMIERA_META_TRAIT_H
+
+
+#include "lib/meta/util.hpp"
+
+#include <boost/type_traits/is_convertible.hpp>
+#include <string>
+
+  
+namespace lumiera {
+namespace typelist {
+  
+  /** Trait template for detecting if a type can be converted to string.
+   *  For example, this allows to write specialisations with the help of
+   *  boost::enable_if
+   */
+  template <typename TY>
+  struct can_ToString
+    {
+      enum { value = boost::is_convertible<TY, std::string>::value
+           };
+    };
+  
+  
+  
+}} // namespace lumiera::typelist
+#endif

tests/40components.tests

@@ -234,6 +234,16 @@ out: dtor ~TargetObj\(12\) successful
 END
 
 
+TEST "formatting/diagnostics helpers" FormatHelper_test <<END
+out: Displaying some types....
+out: «..util.test.Reticent.»
+out: <no comment>
+out: ^hey Joe!
+out: ^he says: hey Joe!
+return: 0
+END
+
+
 TEST "functional closure" FunctionClosure_test <<END
 out: List1	:-<1>-<2>-<3>-
 out: List2	:-<5>-<6>-<7>-

tests/lib/Makefile.am

@@ -43,6 +43,7 @@ test_lib_SOURCES =						\
 	$(testlib_srcdir)/exceptionerrortest.cpp		\
 	$(testlib_srcdir)/factory-special-test.cpp		\
 	$(testlib_srcdir)/factorytest.cpp			\
+	$(testlib_srcdir)/format-helper-test.cpp		\
 	$(testlib_srcdir)/hash-indexed-test.cpp			\
 	$(testlib_srcdir)/helloworldtest.cpp			\
 	$(testlib_srcdir)/lifecycletest.cpp			\

tests/lib/format-helper-test.cpp

@@ -0,0 +1,88 @@
+/*
+  FormatHelper(Test)  -  validate formatting and diagnostics helpers
+ 
+  Copyright (C)         Lumiera.org
+    2009,               Hermann Vosseler <Ichthyostega@web.de>
+ 
+  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 2 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, write to the Free Software
+  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ 
+* *****************************************************/
+
+
+#include "lib/test/run.hpp"
+#include "lib/format.hpp"
+#include "lib/error.hpp"
+
+#include <iostream>
+
+using std::cout;
+using std::endl;
+
+
+namespace util {
+namespace test {
+  
+  class Reticent 
+    {
+    };
+  
+  class UnReticent
+    : public Reticent 
+    {
+    public:
+      operator string()  const { return "hey Joe!"; }
+    };
+  
+  
+  
+  /*************************************************
+   * verifies the proper working of helper functions
+   * frequently used within the Lumiera testsuite.
+   * @see test-helper.hpp
+   */
+  class FormatHelper_test : public Test
+    {
+      void
+      run (Arg)
+        {
+          check2String();
+        }
+      
+      
+      /** @test verify the maybe-to-string conversion. */
+      void
+      check2String ()
+        {
+          std::cout << "Displaying some types....\n";
+          
+          Reticent closeLipped;
+          UnReticent chatterer;
+          
+          cout << str (closeLipped) << endl;
+          cout << str (closeLipped, "he says: ", "<no comment>") << endl;
+          
+          cout << str (chatterer) << endl;
+          cout << str (chatterer, "he says: ", "<no comment>") << endl;
+        }
+      
+      
+      
+    };
+  
+  LAUNCHER (FormatHelper_test, "unit common");
+  
+  
+}} // namespace util::test
+