also refactored core.meow into seperate files in hope that it'll help solve circular imports

core/base_recipe.py

@@ -0,0 +1,68 @@
+
+"""
+This file contains the base MEOW recipe defintion. This should be inherited 
+from for all recipe instances.
+
+Author(s): David Marchant
+"""
+
+from typing import Any, Dict
+
+from core.correctness.vars import get_drt_imp_msg, VALID_RECIPE_NAME_CHARS
+from core.correctness.validation import valid_string, check_implementation
+
+
+class BaseRecipe:
+    # A unique identifier for the recipe
+    name:str
+    # Actual code to run
+    recipe:Any
+    # Possible parameters that could be overridden by a Pattern 
+    parameters:Dict[str, Any]
+    # Additional configuration options
+    requirements:Dict[str, Any]
+    def __init__(self, name:str, recipe:Any, parameters:Dict[str,Any]={}, 
+            requirements:Dict[str,Any]={}):
+        """BaseRecipe Constructor. This will check that any class inheriting 
+        from it implements its validation functions. It will then call these on
+        the input parameters."""
+        check_implementation(type(self)._is_valid_recipe, BaseRecipe)
+        check_implementation(type(self)._is_valid_parameters, BaseRecipe)
+        check_implementation(type(self)._is_valid_requirements, BaseRecipe)
+        self._is_valid_name(name)
+        self.name = name
+        self._is_valid_recipe(recipe)
+        self.recipe = recipe
+        self._is_valid_parameters(parameters)
+        self.parameters = parameters
+        self._is_valid_requirements(requirements)
+        self.requirements = requirements
+
+    def __new__(cls, *args, **kwargs):
+        """A check that this base class is not instantiated itself, only 
+        inherited from"""
+        if cls is BaseRecipe:
+            msg = get_drt_imp_msg(BaseRecipe)
+            raise TypeError(msg)
+        return object.__new__(cls)
+
+    def _is_valid_name(self, name:str)->None:
+        """Validation check for 'name' variable from main constructor. Is 
+        automatically called during initialisation. This does not need to be 
+        overridden by child classes."""
+        valid_string(name, VALID_RECIPE_NAME_CHARS)
+
+    def _is_valid_recipe(self, recipe:Any)->None:
+        """Validation check for 'recipe' variable from main constructor. Must 
+        be implemented by any child class."""
+        pass
+
+    def _is_valid_parameters(self, parameters:Any)->None:
+        """Validation check for 'parameters' variable from main constructor. 
+        Must be implemented by any child class."""
+        pass
+
+    def _is_valid_requirements(self, requirements:Any)->None:
+        """Validation check for 'requirements' variable from main constructor. 
+        Must be implemented by any child class."""
+        pass