dev(ir): add the basis for the frontend IR

- add IntermediateNode base class
- add Add
- add Input

hdk/common/__init__.py

@@ -1,2 +1,2 @@
 """HDK's module for shared data structures and code"""
-from . import data_types
+from . import data_types, representation

hdk/common/representation/__init__.py

@@ -0,0 +1,2 @@
+"""HDK's representation module to represent source programs"""
+from . import intermediate

hdk/common/representation/intermediate.py

@@ -0,0 +1,53 @@
+"""File containing HDK's intermdiate representation of source programs operations"""
+
+from abc import ABC
+from copy import deepcopy
+from typing import Any, Dict, Iterable, List, Optional, Tuple
+
+from ..data_types import BaseValue
+
+
+class IntermediateNode(ABC):
+    """Abstract Base Class to derive from to represent source program operations"""
+
+    inputs: List[BaseValue]
+    outputs: List[BaseValue]
+    op_args: Optional[Tuple[Any, ...]]
+    op_kwargs: Optional[Dict[str, Any]]
+
+    def __init__(
+        self,
+        inputs: Iterable[BaseValue],
+        op_args: Optional[Tuple[Any, ...]] = None,
+        op_kwargs: Optional[Dict[str, Any]] = None,
+    ) -> None:
+        self.inputs = list(inputs)
+        self.op_args = op_args
+        self.op_kwargs = op_kwargs
+
+
+class Add(IntermediateNode):
+    """Addition between two values"""
+
+    def __init__(
+        self,
+        inputs: Iterable[BaseValue],
+    ) -> None:
+        super().__init__(inputs)
+        assert len(self.inputs) == 2
+
+        # For now copy the first input type for the output type
+        # We don't perform checks or enforce consistency here for now, so this is OK
+        self.outputs = [deepcopy(self.inputs[0])]
+
+
+class Input(IntermediateNode):
+    """Node representing an input of the numpy program"""
+
+    def __init__(
+        self,
+        inputs: Iterable[BaseValue],
+    ) -> None:
+        super().__init__(inputs)
+        assert len(self.inputs) == 1
+        self.outputs = [deepcopy(self.inputs[0])]