Support NULL type including value notation

README.md

@@ -142,6 +142,9 @@ The background pattern was downloaded from www.subtlepatterns.com
 Changelog
 =========
 
+1.3.18 (04/2016)
+    - Add support for value notation of NULL type
+
 1.3.17 (04/2016)
     - Add support for value notation of empty SEQUENCEs ("{}")
 

opengeode/AdaGenerator.py

@@ -1704,6 +1704,13 @@ def _boolean(primary):
     return [], unicode(ada_string), []
 
 
+@expression.register(ogAST.PrimNull)
+def _boolean(primary):
+    ''' Generate code for a raw null value  '''
+    ada_string = '0'
+    return [], unicode(ada_string), []
+
+
 @expression.register(ogAST.PrimEmptyString)
 def _empty_string(primary):
     ''' Generate code for an empty SEQUENCE OF: {} '''

opengeode/ogAST.py

@@ -221,6 +221,9 @@ class PrimBoolean(Primary):
     pass
 
 
+class PrimNull(Primary):
+    pass
+
 class PrimConstant(Primary):
     is_raw = False
 

opengeode/ogParser.py

@@ -206,6 +206,11 @@ def is_boolean(ty):
     return find_basic_type(ty).kind == 'BooleanType'
 
 
+def is_null(ty):
+    ''' Return true if a type is a NULL Type '''
+    return find_basic_type(ty).kind == 'NullType'
+
+
 def is_string(ty):
     ''' Return true if a type is a String Type '''
     return find_basic_type(ty).kind in (
@@ -683,6 +688,9 @@ def check_type_compatibility(primary, type_ref, context):
     elif isinstance(primary, ogAST.PrimBoolean) and is_boolean(type_ref):
         return
 
+    elif isinstance(primary, ogAST.PrimNull) and is_null(type_ref):
+        return
+
     elif isinstance(primary, ogAST.PrimEmptyString):
         # Empty strings ("{ }") can be used for arrays and empty records
         if basic_type.kind == 'SequenceOfType':
@@ -1674,6 +1682,10 @@ def primary(root, context):
         prim = ogAST.PrimBoolean()
         prim.value = [root.text.lower()]
         prim.exprType = type('PrBool', (object,), {'kind': 'BooleanType'})
+    elif root.type == lexer.NULL:
+        prim = ogAST.PrimNull()
+        prim.value = [root.text.lower()]
+        prim.exprType = type('PrNull', (object,), {'kind': 'NullType'})
     elif root.type == lexer.FLOAT:
         prim = ogAST.PrimReal()
         prim.value = [root.text]

opengeode/opengeode.py

@@ -117,7 +117,7 @@ except ImportError:
 
 
 __all__ = ['opengeode', 'SDL_Scene', 'SDL_View', 'parse']
-__version__ = '1.3.17'
+__version__ = '1.3.18'
 
 if hasattr(sys, 'frozen'):
     # Detect if we are running on Windows (py2exe-generated)

tests/regression/test-emptysequence/og.pr

 SYSTEM og;
-    /* CIF TEXT (159, 221), (287, 188) */
+    /* CIF TEXT (159, 221), (289, 188) */
     -- Text area for declarations and comments
 
 use dv comment 'dataview.asn';
@@ -18,15 +18,12 @@ signal we;
         CONNECT c AND r;
         /* CIF PROCESS (225, 49), (150, 75) */
         PROCESS og;
-            /* CIF TEXT (57, 58), (474, 158) */
+            /* CIF TEXT (57, 58), (337, 130) */
             --  Test support for empty sequences and NULL type
--- The parser does not support the value notation for NULL types yet
--- this demo proposes  a workaround: define constants in the ASN.1 file
--- and use them when needed to define a variable of one of these types
 
 dcl empty1 EmptySeq := c1;
 
-dcl null1 NullType;
+dcl null1 NullType := NULL;
 
 dcl choice1 ChoiceWithEmptySeq := a: n1;
             /* CIF ENDTEXT */
@@ -34,25 +31,27 @@ dcl choice1 ChoiceWithEmptySeq := a: n1;
             START;
                 /* CIF TASK (137, 276), (115, 35) */
                 TASK empty1 := c1
-                /* CIF COMMENT (272, 276), (138, 35) */
+                /* CIF COMMENT (272, 276), (139, 35) */
                 COMMENT 'Using a constant';
-                /* CIF TASK (140, 326), (110, 35) */
+                /* CIF TASK (138, 326), (112, 35) */
                 TASK empty1 := {}
                 /* CIF COMMENT (270, 326), (135, 35) */
                 COMMENT 'Classic notation';
                 /* CIF TASK (130, 376), (130, 35) */
                 TASK choice1 := b: c1;
-                /* CIF TASK (132, 426), (125, 35) */
+                /* CIF TASK (131, 426), (126, 35) */
                 TASK choice1 := b: {};
-                /* CIF TASK (146, 476), (97, 35) */
+                /* CIF TASK (144, 476), (100, 35) */
                 TASK null1 := n1;
-                /* CIF NEXTSTATE (160, 526), (70, 35) */
+                /* CIF TASK (134, 526), (121, 35) */
+                TASK null1 :=  null;
+                /* CIF NEXTSTATE (160, 576), (70, 35) */
                 NEXTSTATE wait;
             /* CIF STATE (424, 231), (70, 35) */
             STATE wait;
                 /* CIF INPUT (417, 286), (84, 35) */
                 INPUT dd;
-                    /* CIF OUTPUT (415, 336), (89, 35) */
+                    /* CIF OUTPUT (414, 336), (89, 35) */
                     OUTPUT we;
                     /* CIF NEXTSTATE (424, 386), (70, 35) */
                     NEXTSTATE wait;