Implement plugin system

- Add PFDLBaseClasses which is an object that holds the actual classes instantiated
by the PFDL Scheduler (can be overwritten by plugins)
- Add plugin loader class that can load plugins and return a new PFDLBaseClasses object
- Script for merging multiple grammars into a comprehensive grammar
- Adaptions to the existing code base so that the new PFDLBaseClasses are used
- Adaptions to the unit tests and new ones for the plugin classes

pfdl_scheduler/model/array.py

@@ -64,7 +64,7 @@ def __radd__(self, other) -> str:
         return other + str(self)
 
     def __eq__(self, __o: object) -> bool:
-        if isinstance(__o, Array):
+        if hasattr(__o, "values") and hasattr(__o, "length") and hasattr(__o, "type_of_elements"):
             return (
                 self.values == __o.values
                 and self.length == __o.length

pfdl_scheduler/model/instance.py

@@ -88,7 +88,7 @@ def parse_json(
                 error_msg = "Array definition in JSON are not supported in the PFDL."
                 error_handler.print_error(error_msg, context=instance_context)
         elif isinstance(value, dict):
-            inner_struct = parse_json(value, error_handler, instance_context)
+            inner_struct = parse_json(value, error_handler, instance_context, instance_class)
             instance.attributes[identifier] = inner_struct
 
     return instance

pfdl_scheduler/model/struct.py

@@ -64,7 +64,12 @@ def __init__(
         self.context_dict: Dict = {}
 
     def __eq__(self, __o: object) -> bool:
-        if isinstance(__o, Struct):
+        if (
+            hasattr(__o, "name")
+            and hasattr(__o, "attributes")
+            and hasattr(__o, "context")
+            and hasattr(__o, "context_dict")
+        ):
             return (
                 self.name == __o.name
                 and self.attributes == __o.attributes

pfdl_scheduler/parser/pfdl_tree_visitor.py

@@ -9,9 +9,13 @@
 # standard libraries
 from typing import Dict, List, OrderedDict, Tuple, Union
 from pfdl_scheduler.model.instance import Instance
+from pfdl_scheduler.pfdl_base_classes import PFDLBaseClasses
 from pfdl_scheduler.utils import helpers
 from pfdl_scheduler.model.parallel import Parallel
 
+# 3rd party
+from antlr4.tree.Tree import TerminalNodeImpl
+
 # local sources
 from pfdl_scheduler.validation.error_handler import ErrorHandler
 
@@ -45,15 +49,22 @@ class PFDLTreeVisitor(PFDLParserVisitor):
     Attributes:
         error_handler: ErrorHandler instance for printing errors while visiting.
         current_task: Reference to the currently visited Task. Every visitor method can access it.
+        pfdl_base_classes: `PFDLBaseClasses` instance for creating new objects.
     """
 
-    def __init__(self, error_handler: ErrorHandler) -> None:
+    def __init__(
+        self,
+        error_handler: ErrorHandler,
+        pfdl_base_classes: PFDLBaseClasses = PFDLBaseClasses(),
+    ) -> None:
         """Initialize the object.
 
         Args:
-            error_handler: ErrorHandler instance for printing errors while visiting.
+            error_handler: `ErrorHandler` instance for printing errors while visiting.
+            pfdl_base_classes: `PFDLBaseClasses` instance for creating new objects.
         """
         self.error_handler: ErrorHandler = error_handler
+        self.pfdl_base_classes: PFDLBaseClasses = pfdl_base_classes
         self.current_task: Task = None
 
     def visitProgram(self, ctx) -> Process:
@@ -64,7 +75,7 @@ def visitProgram(self, ctx) -> Process:
             for child in ctx.children:
                 process_component = self.visit(child)
 
-                if isinstance(process_component, Struct):
+                if isinstance(process_component, self.pfdl_base_classes.get_class("Struct")):
                     if process_component.name not in process.structs:
                         process.structs[process_component.name] = process_component
                     else:
@@ -73,15 +84,15 @@ def visitProgram(self, ctx) -> Process:
                             "is already defined"
                         )
                         self.error_handler.print_error(error_msg, context=child)
-                elif isinstance(process_component, Task):
+                elif isinstance(process_component, self.pfdl_base_classes.get_class("Task")):
                     if process_component.name not in process.tasks:
                         process.tasks[process_component.name] = process_component
                     else:
                         error_msg = (
                             f"A Task with the name '{process_component.name}' " "is already defined"
                         )
                         self.error_handler.print_error(error_msg, context=child)
-                elif isinstance(process_component, Instance):
+                elif isinstance(process_component, self.pfdl_base_classes.get_class("Instance")):
                     if process_component.name not in process.tasks:
                         process.instances[process_component.name] = process_component
                     else:
@@ -106,8 +117,7 @@ def execute_additional_tasks(self, process: Process) -> None:
         self.add_inherited_attributes_to_structs(process)
 
     def add_inherited_attributes_to_structs(self, process: Process) -> None:
-        """
-        Tries to add attributes inherited from the respective parents to all child structs.
+        """Tries to add attributes inherited from the respective parents to all child structs.
 
         Throws an error if one parent struct name is found to be invalid.
         """
@@ -129,12 +139,19 @@ def visitProgram_statement(self, ctx: PFDLParser.Program_statementContext):
             return self.visit(ctx.children[0])
 
     def addInstancesToAllTasks(self, process: Process) -> None:
+        """Adds all instances to the variables of all tasks in the process.
+
+        This method is necessary to use the instances in expressions.
+
+        Args:
+            process: The `Process` object containing all tasks and instances.
+        """
         for instance in process.instances.values():
             for task in process.tasks.values():
                 task.variables[instance.name] = instance.struct_name
 
     def visitStruct(self, ctx) -> Struct:
-        struct = self.pfdl_base_classes.struct()
+        struct = self.pfdl_base_classes.get_class("Struct")()
         struct.name = ctx.STARTS_WITH_UPPER_C_STR().getText()
         struct.context = ctx
 
@@ -160,7 +177,7 @@ def visitStruct_id(self, ctx: PFDLParser.Struct_idContext) -> str:
         return ctx.children[0].getText()
 
     def visitTask(self, ctx) -> Task:
-        task = Task()
+        task = self.pfdl_base_classes.get_class("Task")()
         task.name = ctx.STARTS_WITH_LOWER_C_STR().getText()
         task.context = ctx
 
@@ -170,8 +187,8 @@ def visitTask(self, ctx) -> Task:
             task.input_parameters = self.visitTask_in(ctx.task_in())
             task.context_dict[IN_KEY] = ctx.task_in()
 
-        for statement_ctx in ctx.statement():
-            statement = self.visitStatement(statement_ctx)
+        for statement_ctx in ctx.taskStatement():
+            statement = self.visitTaskStatement(statement_ctx)
             task.statements.append(statement)
         if ctx.task_out():
             task.output_parameters = self.visitTask_out(ctx.task_out())
@@ -182,7 +199,7 @@ def visitTask(self, ctx) -> Task:
     def visitInstance(self, ctx: PFDLParser.InstanceContext) -> Instance:
         instance_name = ctx.STARTS_WITH_LOWER_C_STR().getText()
         struct_name = self.visitStruct_id(ctx.struct_id())
-        instance = self.pfdl_base_classes.instance(
+        instance = self.pfdl_base_classes.get_class("Instance")(
             name=instance_name, struct_name=struct_name, context=ctx
         )
         self.current_program_component = instance
@@ -192,8 +209,11 @@ def visitInstance(self, ctx: PFDLParser.InstanceContext) -> Instance:
             )
             # JSON value
             if isinstance(attribute_value, Dict):
-                attribute_value = self.pfdl_base_classes.instance.from_json(
-                    attribute_value, self.error_handler, ctx, self.pfdl_base_classes.instance
+                attribute_value = self.pfdl_base_classes.get_class("Instance").from_json(
+                    attribute_value,
+                    self.error_handler,
+                    ctx,
+                    self.pfdl_base_classes.get_class("Instance"),
                 )
             instance.attributes[attribute_name] = attribute_value
             instance.attribute_contexts[attribute_name] = attribute_assignment_ctx
@@ -251,7 +271,7 @@ def visitStatement(
         return statement
 
     def visitService_call(self, ctx: PFDLParser.Service_callContext) -> Service:
-        service = Service()
+        service = self.pfdl_base_classes.get_class("Service")()
         service.context = ctx
 
         service.name = ctx.STARTS_WITH_UPPER_C_STR().getText()
@@ -303,13 +323,15 @@ def visitParameter(self, ctx: PFDLParser.ParameterContext) -> Union[str, List[st
     def visitStruct_initialization(self, ctx: PFDLParser.Struct_initializationContext) -> Struct:
         json_string = ctx.json_object().getText()
 
-        struct = Struct.from_json(json_string, self.error_handler, ctx.json_object())
+        struct = self.pfdl_base_classes.get_class("Struct").from_json(
+            json_string, self.error_handler, ctx.json_object()
+        )
         struct.name = ctx.STARTS_WITH_UPPER_C_STR().getText()
         struct.context = ctx
         return struct
 
     def visitTask_call(self, ctx: PFDLParser.Task_callContext) -> TaskCall:
-        task_call = TaskCall()
+        task_call = self.pfdl_base_classes.get_class("TaskCall")()
         task_call.name = ctx.STARTS_WITH_LOWER_C_STR().getText()
         task_call.context = ctx
 
@@ -329,15 +351,15 @@ def visitTask_call(self, ctx: PFDLParser.Task_callContext) -> TaskCall:
         return task_call
 
     def visitParallel(self, ctx: PFDLParser.ParallelContext) -> Parallel:
-        parallel = Parallel()
+        parallel = self.pfdl_base_classes.get_class("Parallel")()
         parallel.context = ctx
         for task_call_context in ctx.task_call():
             task_call = self.visitTask_call(task_call_context)
             parallel.task_calls.append(task_call)
         return parallel
 
     def visitWhile_loop(self, ctx: PFDLParser.While_loopContext) -> WhileLoop:
-        while_loop = WhileLoop()
+        while_loop = self.pfdl_base_classes.get_class("WhileLoop")()
         while_loop.context = ctx
 
         while_loop.expression = self.visitExpression(ctx.expression())
@@ -348,7 +370,7 @@ def visitWhile_loop(self, ctx: PFDLParser.While_loopContext) -> WhileLoop:
         return while_loop
 
     def visitCounting_loop(self, ctx: PFDLParser.Counting_loopContext) -> CountingLoop:
-        counting_loop = CountingLoop()
+        counting_loop = self.pfdl_base_classes.get_class("CountingLoop")()
         counting_loop.context = ctx
 
         counting_loop.counting_variable = ctx.STARTS_WITH_LOWER_C_STR().getText()
@@ -367,7 +389,7 @@ def visitCounting_loop(self, ctx: PFDLParser.Counting_loopContext) -> CountingLo
         return counting_loop
 
     def visitCondition(self, ctx: PFDLParser.ConditionContext) -> Condition:
-        condition_statement = Condition()
+        condition_statement = self.pfdl_base_classes.get_class("Condition")()
         condition_statement.context = ctx
 
         condition_statement.expression = self.visitExpression(ctx.expression())
@@ -416,7 +438,7 @@ def visitPrimitive(self, ctx: PFDLParser.PrimitiveContext):
         return ctx.getText()
 
     def initializeArray(self, array_ctx: PFDLParser.ArrayContext, variable_type: str) -> Array:
-        array = Array()
+        array = self.pfdl_base_classes.get_class("Array")()
         array.type_of_elements = variable_type
         array.context = array_ctx
         length = self.visitArray(array_ctx)

pfdl_scheduler/petri_net/generator.py

@@ -31,6 +31,7 @@
 
 from pfdl_scheduler.petri_net.drawer import draw_petri_net
 from pfdl_scheduler.petri_net.callbacks import PetriNetCallbacks
+from pfdl_scheduler.pfdl_base_classes import PFDLBaseClasses
 
 plugins.load(["labels", "gv", "clusters"], "snakes.nets", "nets")
 
@@ -82,6 +83,7 @@ class PetriNetGenerator:
         callbacks: A PetriNetCallbacks instance representing functions called while execution.
         generate_test_ids: A boolean indicating if test ids (counting from 0) should be generated.
         used_in_extension: A boolean indicating if the Generator is used within the extension.
+        pfdl_base_classes: An instance of `PFDLBaseClasses`.
     """
 
     def __init__(
@@ -91,6 +93,7 @@ def __init__(
         generate_test_ids: bool = False,
         draw_net: bool = True,
         file_name: str = "petri_net",
+        pfdl_base_classes: PFDLBaseClasses = PFDLBaseClasses(),
     ) -> None:
         """Initialize the object.
 
@@ -100,6 +103,7 @@ def __init__(
             generate_test_ids: A boolean indicating if test ids (counting from 0) should be generated.
             draw_net: A boolean indicating if the petri net should be drawn.
             file_name: The desired filename of the petri net image.
+            pfdl_base_classes: An instance of `PFDLBaseClasses`.
         """
 
         if used_in_extension:
@@ -117,11 +121,12 @@ def __init__(
         self.transition_dict: OrderedDict = OrderedDict()
         self.place_dict: Dict = {}
         self.task_started_uuid: str = ""
-        self.callbacks: PetriNetCallbacks = PetriNetCallbacks()
+        self.callbacks: PetriNetCallbacks = pfdl_base_classes.get_class("PetriNetCallbacks")()
         self.generate_test_ids: bool = generate_test_ids
         self.used_in_extension: bool = used_in_extension
         self.tree = None
         self.file_name = file_name
+        self.pfdl_base_classes = pfdl_base_classes
 
     def add_callback(self, transition_uuid: str, callback_function: Callable, *args: Any) -> None:
         """Registers the given callback function in the transition_dict.
@@ -156,7 +161,7 @@ def generate_petri_net(self, process: Process) -> PetriNet:
         group_uuid = str(uuid.uuid4())
         self.tree = Node(group_uuid, start_task.name)
 
-        task_context = TaskAPI(start_task, None)
+        task_context = self.pfdl_base_classes.get_class("TaskAPI")(start_task, None)
         if self.generate_test_ids:
             task_context.uuid = "0"
 
@@ -244,17 +249,17 @@ def generate_statements(
                 in_loop,
             )
 
-            if isinstance(statement, Service):
+            if isinstance(statement, self.pfdl_base_classes.get_class("Service")):
                 connection_uuids = [self.generate_service(*args)]
-            elif isinstance(statement, TaskCall):
+            elif isinstance(statement, self.pfdl_base_classes.get_class("TaskCall")):
                 connection_uuids = self.generate_task_call(*args)
-            elif isinstance(statement, Parallel):
+            elif isinstance(statement, self.pfdl_base_classes.get_class("Parallel")):
                 connection_uuids = [self.generate_parallel(*args)]
-            elif isinstance(statement, CountingLoop):
+            elif isinstance(statement, self.pfdl_base_classes.get_class("CountingLoop")):
                 connection_uuids = [self.generate_counting_loop(*args)]
-            elif isinstance(statement, WhileLoop):
+            elif isinstance(statement, self.pfdl_base_classes.get_class("WhileLoop")):
                 connection_uuids = [self.generate_while_loop(*args)]
-            elif isinstance(statement, Condition):
+            elif isinstance(statement, self.pfdl_base_classes.get_class("Condition")):
                 connection_uuids = self.generate_condition(*args)
             else:
                 connection_uuids = self.handle_other_statements(*args)
@@ -280,7 +285,9 @@ def generate_service(
         group_uuid = str(uuid.uuid4())
         service_node = Node(group_uuid, service.name, node)
 
-        service_api = ServiceAPI(service, task_context, in_loop=in_loop)
+        service_api = self.pfdl_base_classes.get_class("ServiceAPI")(
+            service, task_context, in_loop=in_loop
+        )
 
         service_started_uuid = create_place(service.name + " started", self.net, service_node)
         service_finished_uuid = create_place(service.name + " finished", self.net, service_node)
@@ -327,7 +334,9 @@ def generate_task_call(
             The uuids of the last transitions of the TaskCall petri net component.
         """
         called_task = self.tasks[task_call.name]
-        new_task_context = TaskAPI(called_task, task_context, task_call=task_call, in_loop=in_loop)
+        new_task_context = self.pfdl_base_classes.get_class("TaskAPI")(
+            called_task, task_context, task_call=task_call, in_loop=in_loop
+        )
 
         group_uuid = str(uuid.uuid4())
         task_node = Node(group_uuid, task_call.name, node)