Implement advanced structs and global instances

- Allow structs to inherit from a parent struct
- Add the Instance component which can be interpreted as a global variable

pfdl_grammar/PFDLParser.g4

@@ -5,20 +5,35 @@ options {
 }
 
 program:
-    (NL | struct | task)* EOF;
+    program_statement* EOF;
+
+program_statement:
+    NL | struct | task | instance;
 
 struct:
-    STRUCT STARTS_WITH_UPPER_C_STR INDENT (variable_definition NL+)+ DEDENT END;
+	STRUCT STARTS_WITH_UPPER_C_STR (COLON struct_id)? INDENT (
+		variable_definition NL+
+	)+ DEDENT END;
+
+struct_id: STARTS_WITH_UPPER_C_STR;
 
 task:
-    TASK STARTS_WITH_LOWER_C_STR INDENT task_in? statement+ task_out? DEDENT END;
+    TASK STARTS_WITH_LOWER_C_STR INDENT task_in? taskStatement+ task_out? DEDENT END;
+
+instance:
+	struct_id STARTS_WITH_LOWER_C_STR INDENT (
+		attribute_assignment NL
+	)+ DEDENT END;
 
 task_in:
     IN INDENT (variable_definition NL+)+ DEDENT;
 
 task_out:
     OUT INDENT (STARTS_WITH_LOWER_C_STR NL+)+ DEDENT;
 
+taskStatement:
+    statement;
+
 statement:
     service_call 
     | task_call
@@ -80,6 +95,9 @@ primitive:
 attribute_access:
     STARTS_WITH_LOWER_C_STR (DOT STARTS_WITH_LOWER_C_STR array?)+;
 
+attribute_assignment:
+	STARTS_WITH_LOWER_C_STR COLON (value | json_object);
+
 array:
     ARRAY_LEFT (INTEGER | STARTS_WITH_LOWER_C_STR)? ARRAY_RIGHT;
 

pfdl_scheduler/model/instance.py

@@ -0,0 +1,94 @@
+# Copyright The PFDL Contributors
+#
+# Licensed under the MIT License.
+# For details on the licensing terms, see the LICENSE file.
+# SPDX-License-Identifier: MIT
+
+"""Contains Instance class."""
+
+# standard libraries
+import uuid
+from numbers import Number
+from typing import Dict, Union
+
+# 3rd party libs
+from antlr4.ParserRuleContext import ParserRuleContext
+
+# local sources
+## PFDL base sources
+from pfdl_scheduler.validation.error_handler import ErrorHandler
+
+
+class Instance:
+    """Represents an Instance in the PFDL.
+
+    Attributes:
+        name: A string representing the name of the Instance.
+        attributes: A dict mapping the attribute names with their values.
+        struct_name: A string refering to the Struct this Instance instanciates.
+        context: ANTLR context object of this class.
+        attribute_contexts: A dict that maps the attribute names to their ANTLR contexts.
+    """
+
+    def __init__(
+        self,
+        name: str = "",
+        attributes: Dict[str, Union[str, Number, bool, "Instance"]] = None,
+        struct_name: str = "",
+        context: ParserRuleContext = None,
+    ) -> None:
+        """Initialize the object.
+
+        Args:
+            name: A string representing the name of the Instance.
+            attributes: A dict mapping the attribute names with their values.
+            struct_name: A string refering to the Struct this Instance instanciates.
+            context: ANTLR context object of this class.
+        """
+        self.name: str = name
+
+        if attributes:
+            self.attributes: Dict[str, Union[str, Number, bool, "Instance"]] = attributes
+        else:
+            self.attributes: Dict[str, Union[str, Number, bool, "Instance"]] = {}
+
+        self.struct_name: str = struct_name
+        self.context: ParserRuleContext = context
+        self.attribute_contexts: Dict = {}
+
+    @classmethod
+    def from_json(
+        cls,
+        json_object: Dict,
+        error_handler: ErrorHandler,
+        struct_context: ParserRuleContext,
+        instance_class="Instance",
+    ):
+        return parse_json(json_object, error_handler, struct_context, instance_class)
+
+
+def parse_json(
+    json_object: Dict,
+    error_handler: ErrorHandler,
+    instance_context: ParserRuleContext,
+    instance_class=Instance,
+) -> Instance:
+    """Parses the JSON Struct initialization.
+
+    Returns:
+        An Instance object representing the initialized instance.
+    """
+    instance = instance_class()
+    instance.context = instance_context
+    for identifier, value in json_object.items():
+        if isinstance(value, (int, str, bool)):
+            instance.attributes[identifier] = value
+        elif isinstance(value, list):
+            if error_handler and instance_context:
+                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)
+            instance.attributes[identifier] = inner_struct
+
+    return instance

pfdl_scheduler/model/process.py

@@ -11,6 +11,7 @@
 from typing import Dict
 
 # local sources
+from pfdl_scheduler.model.instance import Instance
 from pfdl_scheduler.model.struct import Struct
 from pfdl_scheduler.model.task import Task
 
@@ -25,20 +26,23 @@ class Process:
     Attributes:
         structs: A dict for mapping the Struct names to the Struct objects.
         task: A dict for mapping the Task names to the Task objects.
+        instances: A dict for mappign the Instance names to the Instance objects.
         start_task_name: the name of the start task of the PFDL program (typically "productionTask").
     """
 
     def __init__(
         self,
         structs: Dict[str, Struct] = None,
         tasks: Dict[str, Task] = None,
+        instances: Dict[str, Instance] = None,
         start_task_name: str = "productionTask",
     ) -> None:
         """Initialize the object.
 
         Args:
             structs: A dict for mapping the Struct names to the Struct objects.
             tasks: A dict for mapping the Task names to the Task objects.
+            instances: A dict for mappign the Instance names to the Instance objects.
             start_task_name: the name of the start task of the PFDL program (typically "productionTask").
         """
         if structs:
@@ -49,4 +53,8 @@ def __init__(
             self.tasks: Dict[str, Task] = tasks
         else:
             self.tasks: Dict[str, Task] = {}
+        if instances:
+            self.instances: Dict[str, Task] = instances
+        else:
+            self.instances: Dict[str, Task] = {}
         self.start_task_name = start_task_name

pfdl_scheduler/model/struct.py

@@ -31,6 +31,8 @@ class Struct:
         name: A string representing the name of the Struct.
         attributes: A dict which maps the attribute names to the defined type
                     or a value (if its a instantiated struct).
+        parent_struct_name: A string representin the identifier of the parent struct
+                            from which this struct inherits the attributes
         context: ANTLR context object of this class.
         context_dict: Maps other attributes with ANTLR context objects.
     """
@@ -39,6 +41,7 @@ def __init__(
         self,
         name: str = "",
         attributes: Dict[str, Union[str, Array, "Struct"]] = None,
+        parent_struct_name: str = "",
         context: ParserRuleContext = None,
     ) -> None:
         """Initialize the object.
@@ -47,13 +50,16 @@ def __init__(
             name: A string representing the name of the Struct.
             attributes: A dict which maps the attribute names to the defined type
                         or a value (if its a instantiated struct).
+            parent_struct_name: A string representin the identifier of the parent struct
+                            from which this struct inherits the attributes
             context: ANTLR context object of this class.
         """
         self.name: str = name
         if attributes:
             self.attributes: Dict[str, Union[str, Array, "Struct"]] = attributes
         else:
             self.attributes: Dict[str, Union[str, Array, "Struct"]] = {}
+        self.parent_struct_name: str = parent_struct_name
         self.context: ParserRuleContext = context
         self.context_dict: Dict = {}