Add message field assignment statement

Ref. AdaCore/RecordFlux#1067

Makefile

@@ -1,6 +1,6 @@
 VERBOSE ?= @
 
-VERSION = 0.10.0
+VERSION = 0.11.0
 BUILDDIR = $(PWD)/build
 
 ifneq ($(MAKECMDGOALS),clean)

language/parser.py

@@ -501,6 +501,13 @@
     assignment_statement=ast.Assignment(
         grammar.unqualified_identifier, ":=", grammar.extended_expression
     ),
+    message_field_assignment_statement=ast.MessageFieldAssignment(
+        grammar.unqualified_identifier,
+        ".",
+        grammar.unqualified_identifier,
+        ":=",
+        grammar.extended_expression,
+    ),
     list_attribute=ast.AttributeStatement(
         grammar.unqualified_identifier,
         "'",
@@ -522,7 +529,11 @@
         Opt("(", List(grammar.message_aggregate_association, sep=","), ")"),
     ),
     attribute_statement=Or(grammar.list_attribute, grammar.reset),
-    action=Or(grammar.assignment_statement, grammar.attribute_statement),
+    action=Or(
+        grammar.assignment_statement,
+        grammar.message_field_assignment_statement,
+        grammar.attribute_statement,
+    ),
     conditional_transition=ast.ConditionalTransition(
         "goto",
         grammar.unqualified_identifier,

language/rflx_ast.py

@@ -200,6 +200,14 @@ class Assignment(Statement):
     expression = Field(type=Expr)
 
 
+class MessageFieldAssignment(Statement):
+    """Assignment of expression to message field."""
+
+    message = Field(type=UnqualifiedID)
+    field = Field(type=UnqualifiedID)
+    expression = Field(type=Expr)
+
+
 class AttrStmt(RFLXNode):
     """Attribute statement kind."""
 

tests/grammar_test.py

@@ -2848,6 +2848,32 @@ def test_assignment_statement(string: str, expected: Dict[str, str]) -> None:
     assert actual == expected
 
 
+@pytest.mark.parametrize(
+    "string,expected",
+    [
+        (
+            "A.B := C",
+            {
+                "_kind": "MessageFieldAssignment",
+                "expression": {
+                    "_kind": "Variable",
+                    "identifier": {
+                        "_kind": "ID",
+                        "name": {"_kind": "UnqualifiedID", "_value": "C"},
+                        "package": None,
+                    },
+                },
+                "message": {"_kind": "UnqualifiedID", "_value": "A"},
+                "field": {"_kind": "UnqualifiedID", "_value": "B"},
+            },
+        )
+    ],
+)
+def test_message_field_assignment_statement(string: str, expected: Dict[str, str]) -> None:
+    actual = parse(string, GrammarRule.message_field_assignment_statement_rule)
+    assert actual == expected
+
+
 @pytest.mark.parametrize(
     "string,expected",
     [