feat: add some extractor

src/frontend/extractor/aust_extractor.py

@@ -1,3 +1,5 @@
+from typing import cast
+from pylatexenc.latexwalker import LatexNode, LatexMacroNode
 from .common import Extractor
 
 class AustExtractor(Extractor):
@@ -5,4 +7,14 @@ class AustExtractor(Extractor):
     def __init__(self) -> None:
         pass
 
+    def extract_include_command(self, node: LatexNode) -> str | None:
+        if not isinstance(node, LatexMacroNode):
+            return None
 
+        macro_name = cast(str, node.macroname)
+        match macro_name:
+            case 'include' | 'input':
+                # TODO: handle include command
+                return None
+            case _:
+                return None

src/frontend/extractor/common.py

@@ -1,7 +1,21 @@
 from abc import ABC, abstractmethod
+from pylatexenc.latexwalker import LatexNode, LatexMacroNode
 
 class Extractor(ABC):
-    pass
+    """
+    An abstract base class for all extractors.
+
+    Extractors are used to extract information from LaTeX nodes.
+    """
+    @abstractmethod
+    def extract_include_command(self, node: LatexNode) -> str | None:
+        """
+        Extract the include command from a LaTeX node.
+        
+        :param node: The LaTeX node to extract the include command from.
+        :return: The path to the include file, otherwise None.
+        """
+        pass