Update code generation to account for null syntax fields

TN: R925-010

Author: pmderodat

langkit/compiled_types.py

@@ -2275,8 +2275,9 @@ def set_types(self, types):
 
         :type types: list[CompiledType]
         """
-        fields = self.get_parse_fields(predicate=lambda f: not f.abstract,
-                                       concrete_order=True)
+        fields = self.get_parse_fields(
+            predicate=lambda f: not f.abstract and not f.null,
+            concrete_order=True)
 
         check_source_language(
             len(fields) == len(types), '{} has {} fields ({} types given). You'

langkit/expressions/structs.py

@@ -321,9 +321,16 @@ def error_if_not_empty(name_set, message):
         # Create a dict of field names to fields in the struct type
 
         def is_required(f):
-            return (self.struct_type.is_struct_type
-                    if isinstance(f, BuiltinField) else
-                    isinstance(f, (Field, UserField)))
+            if isinstance(f, BuiltinField):
+                # BuiltinFields are actually stored fields only for structure
+                # types (not for nodes).
+                return self.struct_type.is_struct_type
+
+            elif isinstance(f, Field):
+                return not f.null
+
+            else:
+                return isinstance(f, UserField)
 
         required_fields = {
             f._name.lower: f

langkit/parsers.py

@@ -1579,7 +1579,7 @@ def compute_fields_types(self):
         # fields in the destination node are the same.
         nb_transform_values = len(fields_types)
         nb_fields = len(typ.get_parse_fields(
-            predicate=lambda f: not f.abstract))
+            predicate=lambda f: not f.abstract and not f.null))
         check_source_language(
             nb_transform_values == nb_fields,
             'Transform parser generates {} values, but {} has {} fields'

langkit/templates/astnode_types_ada.mako

@@ -86,13 +86,18 @@
       % if field.abstract:
          case ${field.struct.ada_kind_name} (Node.Kind) is
             % for cf in field.concrete_fields:
-               when ${cf.struct.ada_kind_name} =>
-                  declare
-                     N : constant ${cf.struct.name} :=
-                        ${cf.struct.name} (Node);
-                  begin
-                     ${return_value('N')}
-                  end;
+               when ${' | '.join(n.ada_kind_name
+                                 for n in cf.struct.concrete_subclasses)} =>
+                  % if cf.null:
+                     return ${cf.type.nullexpr};
+                  % else:
+                     declare
+                        N : constant ${cf.struct.name} :=
+                           ${cf.struct.name} (Node);
+                     begin
+                        ${return_value('N')}
+                     end;
+                  % endif
             % endfor
          end case;
       % else:
@@ -173,7 +178,9 @@
    <%
       fields = cls.get_fields(
          include_inherited=False,
-         predicate=lambda f: f.should_emit and not f.abstract)
+         predicate=lambda f: (f.should_emit and
+                              not f.abstract and
+                              not f.null))
       ext = ctx.ext('nodes', cls.raw_name, 'components')
    %>
    % if fields:

langkit/templates/parsers/transform_code_ada.mako

@@ -38,7 +38,7 @@ if ${parser.pos_var} /= No_Token_Index then
       else ${parser.pos_var} - 1);
    <% fields_n_args = zip(
          parser.get_type().get_parse_fields(
-            predicate=lambda f: not f.abstract,
+            predicate=lambda f: not f.abstract and not f.null,
             concrete_order=True),
          args) %>
 

langkit/templates/pkg_analysis_body_ada.mako

@@ -718,7 +718,7 @@ package body ${ada_lib_name}.Analysis is
 
       % for f in e.element_type.get_parse_fields( \
          include_inherited=False, \
-         predicate=lambda f: f.is_public \
+         predicate=lambda f: f.is_public and not f.overriding \
       ):
          ${astnode_types.field_body(f)}
       % endfor

langkit/templates/pkg_implementation_body_ada.mako

@@ -2290,7 +2290,7 @@ package body ${ada_lib_name}.Implementation is
 
         def get_actions(astnode, node_expr):
             specific_fields = astnode.get_parse_fields(
-                lambda f: not f.abstract,
+                lambda f: not f.abstract and not f.null,
                 include_inherited=False
             )
 
@@ -2315,7 +2315,7 @@ package body ${ada_lib_name}.Implementation is
             elif specific_fields:
                 # Compute the index of the first AST node field we handle here
                 all_fields = astnode.get_parse_fields(
-                    lambda f: not f.abstract,
+                    lambda f: not f.abstract and not f.null,
                     include_inherited=True
                 )
                 first_field_index = len(all_fields) - len(specific_fields) + 1

langkit/templates/pkg_implementation_spec_ada.mako

@@ -381,7 +381,7 @@ private package ${ada_lib_name}.Implementation is
      (${', \n'.join(
            '{} => {}'.format(
               cls.ada_kind_name,
-              (len(cls.get_parse_fields(lambda f: f.type.is_ast_node))
+              (len(cls.get_parse_fields(lambda f: not f.null))
                if not cls.is_list_type else -1)
            )
            for cls in ctx.astnode_types if not cls.abstract)});

langkit/templates/pkg_introspection_body_ada.mako

@@ -45,7 +45,10 @@ package body ${ada_lib_name}.Introspection is
             % for n in concrete_astnodes:
                when ${n.ada_kind_name} =>
                return (case Field is
-                       % for f in n.get_parse_fields(concrete_order=True):
+                       % for f in n.get_parse_fields( \
+                          predicate=lambda f: not f.null, \
+                          concrete_order=True \
+                       ):
                        when ${enum_literal(f)} => ${f.index + 1},
                        % endfor
                        when others => raise Constraint_Error);
@@ -68,7 +71,7 @@ package body ${ada_lib_name}.Introspection is
       <%
          def get_actions(astnode, node_expr):
             fields = astnode.get_parse_fields(
-               predicate=lambda f: not f.abstract,
+               predicate=lambda f: not f.abstract and not f.null,
                include_inherited=False
             )
             result = []

langkit/templates/pkg_iterators_body_ada.mako

@@ -449,23 +449,29 @@ package body ${ada_lib_name}.Iterators is
    --------------
 
    overriding function Evaluate
-     (P : in out Child_With_Predicate; N : ${node}) return Boolean
-   is
-      Field_Index : Positive;
+     (P : in out Child_With_Predicate; N : ${node}) return Boolean is
    begin
       if N.Is_Null then
          return False;
       end if;
 
-      --  First check that N has the requested field
-      begin
-         Field_Index := Index (N.Kind, P.Field);
-      exception
-         when Invalid_Field =>
-            return False;
-      end;
-
-      return P.Predicate.Unchecked_Get.Evaluate (N.Child (Field_Index));
+      % if ctx.sorted_parse_fields:
+         declare
+            Field_Index : Positive;
+         begin
+            --  First check that N has the requested field
+            begin
+               Field_Index := Index (N.Kind, P.Field);
+            exception
+               when Invalid_Field =>
+                  return False;
+            end;
+
+            return P.Predicate.Unchecked_Get.Evaluate (N.Child (Field_Index));
+         end;
+      % else:
+         return False;
+      % endif
    end Evaluate;
 
    --------------