Improvements to Jinja context helpers

add _ctx_ as a short alias for __utils__
add get and set functions as aliases of get_var set_var
make get have a default for non pre-existing variables
make set return the value it is setting for jinja render purposes
make all variables created with get/set directly available in the context

src/ibek/gen_scripts.py

@@ -50,7 +50,12 @@ def create_boot_script(entities: Sequence[Entity]) -> str:
     renderer = Render()
 
     return template.render(
+        # old name for global context for backward compatibility
         __utils__=UTILS,
+        # new short name for global context
+        _ctx_=UTILS,
+        # put variables created with set/get directly in the context
+        **UTILS.variables,
         env_var_elements=renderer.render_environment_variable_elements(entities),
         script_elements=renderer.render_pre_ioc_init_elements(entities),
         post_ioc_init_elements=renderer.render_post_ioc_init_elements(entities),

src/ibek/render_db.py

@@ -76,7 +76,7 @@ def add_database(self, database: Database, entity: Entity) -> None:
 
             for arg, value in database.args.items():
                 if value is None:
-                    if arg not in entity.__dict__:
+                    if arg not in entity.__dict__ and arg not in UTILS.variables:
                         raise ValueError(
                             f"database arg '{arg}' in database template "
                             f"'{database.file}' not found in context"

src/ibek/utils.py

@@ -32,6 +32,12 @@ def increment(self, count: int):
                 f"Counter {self.current} exceeded stop value of {self.stop}"
             )
 
+    def __repr__(self) -> str:
+        return str(self.current)
+
+    def __str__(self) -> str:
+        return str(self.current)
+
 
 class Utils:
     """
@@ -43,6 +49,10 @@ def __init__(self: "Utils"):
         self.ioc_name: str = ""
         self.__reset__()
 
+        # old names for backward compatibility
+        self.set_var = self.set
+        self.get_var = self.get
+
     def __reset__(self: "Utils"):
         """
         Reset all saved state. For use in testing where more than one
@@ -69,13 +79,15 @@ def get_env(self, key: str) -> str:
         """
         return os.environ.get(key, "")
 
-    def set_var(self, key: str, value: Any):
+    def set(self, key: str, value: Any) -> Any:
         """create a global variable for our jinja context"""
         self.variables[key] = value
+        return value
 
-    def get_var(self, key: str) -> Any:
+    def get(self, key: str, default="") -> Any:
         """get the value a global variable for our jinja context"""
-        return self.variables.get(key, "")
+        # default is used to set an initial value if the variable is not set
+        return self.variables.get(key, default)
 
     def counter(
         self, name: str, start: int = 0, stop: int = 65535, inc: int = 1
@@ -113,7 +125,12 @@ def render(self, context: Any, template_text: Any) -> str:
             jinja_template = Template(template_text, undefined=StrictUndefined)
             return jinja_template.render(
                 context,
+                # old name for global context for backward compatibility
                 __utils__=self,
+                # new short name for global context
+                _ctx_=self,
+                # put variables created with set/get directly in the context
+                **self.variables,
                 ioc_yaml_file_name=self.file_name,
                 ioc_name=self.ioc_name,
             )