Improve C++ code generation for terms.

src/libterm/term.hh

@@ -170,70 +170,123 @@ namespace term
   };
 
 
+// a few shortcuts to keep things clear.
+
 # define TRM_NIL
 # define TRM_NIL_ARGS(...)
+# define TRM_EMPTY_ARRAY  (0, ())
 
-# define TRM_ARRAY_DATA(Array) BOOST_PP_ARRAY_DATA(Array)
+# define TRM_SEQ_HEAD BOOST_PP_SEQ_HEAD
-# define TRM_ARRAY_SIZE(Array) BOOST_PP_ARRAY_SIZE(Array)
+# define TRM_SEQ_TAIL BOOST_PP_SEQ_TAIL
+
+# define TRM_ARRAY_DATA BOOST_PP_ARRAY_DATA
+# define TRM_ARRAY_SIZE BOOST_PP_ARRAY_SIZE
+# define TRM_ARRAY_ELEM BOOST_PP_ARRAY_ELEM
+# define TRM_SEQ_TO_ARRAY BOOST_PP_SEQ_TO_ARRAY
+# define TRM_ARRAY_TO_SEQ(Array)                                        \
+  BOOST_PP_TUPLE_TO_SEQ(TRM_ARRAY_SIZE(Array), TRM_ARRAY_DATA(Array))
+
+// TRM_EVAL macros are used to do the convertion of array to sequence and to
+// provide a default case when the array cannot be converted into a
+// sequence.  This case happens when you need to convert a zero size array.
 
 # define TRM_EVAL_0(Macro1, Macro2, Array, Default) Default
-  /*
+# define TRM_EVAL_1(Macro1, Macro2, Array, Default)     \
- define TRM_EVAL_1(Macro1, Macro2, Array, Default)                     \
+  Macro1(Macro2, TRM_ARRAY_TO_SEQ(Array))
-  Macro1(Macro2, BOOST_PP_TUPLE_TO_SEQ(TRM_ARRAY_SIZE(Array), TRM_ARRAY_DATA(Array)))
+
-  */
 # define TRM_EVAL_2 TRM_EVAL_1
 # define TRM_EVAL_3 TRM_EVAL_1
 # define TRM_EVAL_4 TRM_EVAL_1
 
 # define TRM_EVAL_II(eval) eval
-# define TRM_EVAL_I(n, tuple) TRM_EVAL_ ## n
+# define TRM_EVAL_I(n, _) TRM_EVAL_ ## n
 # define TRM_EVAL(Macro1, Macro2, Array, Default)                       \
   TRM_EVAL_II(TRM_EVAL_I Array (Macro1, Macro2, Array, Default))
 
+# define TRM_DEFAULT1(D0)  D0
+
+// Default TRM_<fun> are taking an array and return a sequence.  To keep the
+// same type, you need to specify which type you expect to have.  The reason
+// is that array support to have no values where sequence do not support it.
+// On the contrary, all operations are well defined on sequences but none
+// are defined on arrays.
 
 # define TRM_MAP_HELPER(R, Macro, Elt) (Macro(Elt))
 # define TRM_MAP_(Macro, Seq)                           \
   BOOST_PP_SEQ_FOR_EACH(TRM_MAP_HELPER, Macro, Seq)
 # define TRM_MAP_SEQ(Macro, Seq)                \
   TRM_MAP_(Macro, Seq)
-# define TRM_MAP_SEQ_TO_ARRAY(Macro, Seq)               \
+# define TRM_MAP_ARRAY_(Macro, Seq)             \
-  BOOST_PP_SEQ_TO_ARRAY(TRM_MAP_SEQ(Macro, Seq))
+  TRM_SEQ_TO_ARRAY(TRM_MAP_SEQ(Macro, Seq))
 # define TRM_MAP_ARRAY(Macro, Array)            \
-  TRM_EVAL(TRM_MAP_SEQ_TO_ARRAY, Macro, Array, (0, ()))
+  TRM_EVAL(TRM_MAP_ARRAY_, Macro, Array,        \
+    TRM_DEFAULT1(TRM_EMPTY_ARRAY)               \
+  )
 # define TRM_MAP(Macro, Array)                  \
-  TRM_EVAL(TRM_MAP_SEQ, Macro, Array, TRM_NIL)
+  TRM_EVAL(TRM_MAP_SEQ, Macro, Array,           \
+    TRM_DEFAULT1(TRM_NIL)                       \
+  )
+
+// Apply a macro on all elements (array / sequence)
 
 # define TRM_APPLY_HELPER(R, Macro, Elt) Macro(Elt)
 # define TRM_APPLY_(Macro, Seq)                         \
-  BOOST_PP_SEQ_FOR_EACH(TRM_MAP_HELPER, Macro, Seq)
+  BOOST_PP_SEQ_FOR_EACH(TRM_APPLY_HELPER, Macro, Seq)
 # define TRM_APPLY_SEQ(Macro, Seq)              \
   TRM_APPLY_(Macro, Seq)
 # define TRM_APPLY(Macro, Array)                \
-  TRM_EVAL(TRM_APPLY_, Macro, Array, TRM_NIL)
+  TRM_EVAL(TRM_APPLY_, Macro, Array,            \
+    TRM_DEFAULT1(TRM_NIL)                       \
+  )
 
-# define TRM_HEAD(Seq) BOOST_PP_SEQ_HEAD(Seq)
+// Apply a macro on all elements (array / sequence) and separate them by a
-# define TRM_TAIL(Seq) BOOST_PP_SEQ_TAIL(Seq)
+// comma.
 
 # define TRM_SEPARATE_COMMA_HELPER(Elt) , Elt
 # define TRM_SEPARATE_COMMA_(_, Seq)                                    \
-  TRM_HEAD(Seq) TRM_APPLY_SEQ(TRM_SEPARATE_COMMA_HELPER, TRM_TAIL(Seq))
+  TRM_SEQ_HEAD(Seq)
+  TRM_APPLY_SEQ(TRM_SEPARATE_COMMA_HELPER, TRM_SEQ_TAIL(Seq))
 # define TRM_SEPARATE_COMMA_SEQ(Seq)            \
-  TRM_SEPARATE_COMMA_(dummy, Seq)
+  TRM_SEPARATE_COMMA(TRM_SEQ_TO_ARRAY(Seq))
 # define TRM_SEPARATE_COMMA(Array)                      \
-  TRM_EVAL(TRM_SEPARATE_COMMA_, dummy, Array, TRM_NIL)
+  TRM_EVAL(TRM_SEPARATE_COMMA_, dummy, Array,           \
+    TRM_DEFAULT1(TRM_NIL)     \
+  )
 
+// These macro are used to define how to manipulate each argument.  If the
+// argument should be given by reference or by copy.  You should use
+// references when the element goes over a specific size and if you accept
+// to see it living on the stack.  You should use copies when the element is
+// small and if you prefer to have it inside a register.
 
-# define TRM_TYPE_REF(Type, Name) const Type&, Type &, Name
+# define TRM_TYPE_REF(Type, Name) (const Type&, Type &, Name)
-# define TRM_TYPE_COPY(Type, Name) const Type, Type &, Name
+# define TRM_TYPE_COPY(Type, Name) (const Type, Type &, Name)
 # define TRM_TYPE_TERM(Type, Name) TRM_TYPE_COPY(A ## Type, Name)
 
-# define TRM_CONST_ABSTRACT_COPY_DECL(Copy, Ref, Name)  Copy Name;
+// Handle the different usage of the variables.  Arguments are suffixed with
-# define TRM_CONST_ABSTRACT_COPY_ARG(Copy, Ref, Name)  Copy Name ## _
+// a '_' and attributes are not.
-# define TRM_ABSTRACT_REF_ARG(Copy, Ref, Name)  Ref Name ## _
+
-# define TRM_INIT_ATTRIBUTES(Copy, Ref, Name)  Name (Name ## _)
+# define TRM_CONST_ABSTRACT_COPY_DECL_(Copy, Ref, Name) Copy Name;
-# define TRM_ARGUMENTS(Copy, Ref, Name)  Name ## _
+# define TRM_CONST_ABSTRACT_COPY_ARG_(Copy, Ref, Name)  Copy Name ## _
-# define TRM_COPY_IN_ARG(Copy, Ref, Name)  Name ## _ = Name;
+# define TRM_ABSTRACT_REF_ARG_(Copy, Ref, Name)  Ref Name ## _
-# define TRM_LESS_RHS_OR(Copy, Ref, Name)  Name < rhs. Name ||
+# define TRM_INIT_ATTRIBUTES_(Copy, Ref, Name)  Name (Name ## _)
+# define TRM_ARGUMENTS_(Copy, Ref, Name)  Name ## _
+# define TRM_COPY_IN_ARG_(Copy, Ref, Name)  Name ## _ = Name;
+# define TRM_LESS_RHS_OR_(Copy, Ref, Name)  Name < rhs. Name ||
+
+// These macro are shortcuts used to remove extra parenthesies added by
+// TRM_TYPE_* macros.  Without such parenthesies TRM_APPLY_HELPER won't be
+// able to give the argument to these macros and arrays won't be well
+// formed.
+
+# define TRM_CONST_ABSTRACT_COPY_DECL(Elt) TRM_CONST_ABSTRACT_COPY_DECL_ Elt
+# define TRM_CONST_ABSTRACT_COPY_ARG(Elt) TRM_CONST_ABSTRACT_COPY_ARG_ Elt
+# define TRM_ABSTRACT_REF_ARG(Elt) TRM_ABSTRACT_REF_ARG_ Elt
+# define TRM_INIT_ATTRIBUTES(Elt) TRM_INIT_ATTRIBUTES_ Elt
+# define TRM_ARGUMENTS(Elt) TRM_ARGUMENTS_ Elt
+# define TRM_COPY_IN_ARG(Elt) TRM_COPY_IN_ARG_ Elt
+# define TRM_LESS_RHS_OR(Elt) TRM_LESS_RHS_OR_ Elt
+
 
 // Add the implementation class as a friend class to provide access to the
 // private constructor.  This reduce interaction with the implementation of
@@ -301,7 +354,7 @@ namespace term
       this_type* ptr;                                                   \
       if (ptr = dynamic_cast<this_type*>(t.ptr_))                       \
       {                                                                 \
-        TRM_MAP(TRM_COPY_IN_ARG, Attributes);                           \
+        TRM_APPLY(TRM_COPY_IN_ARG, Attributes);                         \
         return parent::match ## Base (                                  \
           TRM_SEPARATE_COMMA_SEQ(                                       \
             ( t )                                                       \
@@ -321,7 +374,7 @@ namespace term
     inline                                                              \
     bool operator <(const Name& rhs)                                    \
     {                                                                   \
-      return TRM_MAP(TRM_LESS_RHS_OR, Attributes)                       \
+      return TRM_APPLY(TRM_LESS_RHS_OR, Attributes)                     \
         parent::operator < (rhs);                                       \
     }
 
@@ -329,7 +382,7 @@ namespace term
 // Declare all the attributes of the current class.
 # define TRM_ATTRIBUTE_DECLS(Name, Base, Attributes, BaseArgs)  \
   public:                                                       \
-    TRM_MAP(TRM_CONST_ABSTRACT_COPY_DECL, Attributes)
+    TRM_APPLY(TRM_CONST_ABSTRACT_COPY_DECL, Attributes)
 
 
 // A class which provide static method (no virtual) to access the