vsc_ast: bring back AST root node

After short discussion we have decided to bring back the AST node.
This node is always a root, but inherits everything from the Namespace class.

And vsc_parser.gen() function now accepts object of any type. Later we
might want to introduce some checks for the passed node, like
assert dataclass.is_dataclass(node).

Signed-off-by: Mikhail Tsukerman <mikhail.tcukerman@daimler.com>
Signed-off-by: Magnus Feuer <magnus.feuer@mercedes-benz.com>

tests/gen_test.py

@@ -37,12 +37,12 @@ def test_ast_gen():
 
 
 def test_ast_manual():
- namespace = vsc_ast.Namespace(name='test', description='test', major_version=1, minor_version=0)
+ service = vsc_ast.AST(name='test', description='test', major_version=1, minor_version=0)
 
- assert namespace.name == 'test'
- assert namespace.description == 'test'
- assert namespace.major_version == 1
- assert namespace.minor_version == 0
+ assert service.name == 'test'
+ assert service.description == 'test'
+ assert service.major_version == 1
+ assert service.minor_version == 0
 
 
 # Unused

vsc/model/vsc_ast.py

@@ -114,6 +114,10 @@ class Namespace:
 
  namespaces: Optional[List['Namespace']] = field(default_factory=lambda: [])
 
+@dataclass
+class AST(Namespace):
+ pass
+
 
 def read_yaml_file(filename) -> str:
  """
@@ -135,7 +139,7 @@ def parse_yaml_file(yaml_string: str) -> Dict[Any, Any]:
  return yaml.safe_load(yaml_string)
 
 
-def read_ast_from_yaml_file(filename: str) -> Namespace:
+def read_ast_from_yaml_file(filename: str) -> AST:
  """
  Reads a yaml file and returns AST
  :param filename: path to a yaml file
@@ -146,6 +150,6 @@ def read_ast_from_yaml_file(filename: str) -> Namespace:
 
  yaml_dict = parse_yaml_file(yaml_string)
 
- ast = dacite.from_dict(data_class=Namespace, data=yaml_dict)
+ ast = dacite.from_dict(data_class=AST, data=yaml_dict)
 
  return ast

vsc/model/vsc_generator.py

@@ -12,15 +12,15 @@
 
 # This performs the following related functions:
 
-# 1. As input.yaml we expect an Namespace as provided by the parser module
+# 1. As input.yaml we expect an AST as provided by the parser module
 #
 # 2. It uses jinja2 templating library to generate code or configuration
 # according to given templates.
 
 # For other features from parser module
 from vsc.model import vsc_ast
-from vsc.model.vsc_ast import Namespace
 from vsc.templates import TemplatePath
+from typing import Generic, TypeVar
 import jinja2
 import sys
 
@@ -44,6 +44,7 @@
 
 default_templates = {}
 
+T = TypeVar('T')
 
 # Exception:
 class GeneratorError(BaseException):
@@ -58,7 +59,7 @@ def get_template(filename):
  return jinja_env.get_template(filename)
 
 # gen() function to be called from templates
-def gen(node : Namespace, template_file = None):
+def gen(node : Generic[T], template_file = None):
  # Processing of lists of objects?
 
  if node is None:
@@ -80,7 +81,7 @@ def gen(node : Namespace, template_file = None):
  raise GeneratorError(f'Wrong use of gen() function! Usage: pass the node as first argument (you passed a {type(node)}), and optionally template name (str) as second argument. (You passed a {template_file.__name__})')
 
 # gen helper function:
-def _gen_with_default_template(node : Namespace):
+def _gen_with_default_template(node : Generic[T]):
 
  # None is for a field that exists in Namespace definition, but was not given
  # a value in the YAML (=> happens only if it was an optional item).
@@ -111,7 +112,7 @@ def _gen_with_default_template(node : Namespace):
 
 # Instead of providing a template file, provide the template text itself
 # (for unit tests mostly). See gen() for more comments/explanation.
-def gen_template_text(node: Namespace, template_text: str):
+def gen_template_text(node: Generic[T], template_text: str):
  # Processing of lists of objects, see gen() for explanation
  if type(node) == list or type(node) == tuple:
  return [gen_template_text(x, template_text) for x in node]
@@ -139,7 +140,7 @@ def usage():
 # This is a default definition for our current generation tests.
 # It may need to be changed, or defined differently in a custom generator
 default_templates = {
- 'Namespace': 'Namespace-simple_doc.tpl',
+ 'AST': 'AST-simple_doc.tpl',
  'Service': 'Service-simple_doc.html',
  'Argument': 'Argument-simple_doc.html',
  'Error': 'Error-simple_doc.html',