feat: add task 2 calculator draft

task2/tokenizer.py

@@ -0,0 +1,39 @@
+from collections import deque
+from typing import Iterable, Literal, Optional
+
+from math_objects import Integer, Operator, Parenthesis, Token
+
+
+def tokenize(string: str) -> Iterable[Token]:
+    buffer: deque[str] = deque()
+    prediction: Optional[Literal["number"]] = None
+
+    def _take_buffer() -> str:
+        string = "".join(buffer)
+        buffer.clear()
+        return string
+
+    for c in string:
+        if c.isdigit():
+            if prediction != "number" and buffer:
+                yield Integer.create_from_string(_take_buffer())
+                prediction = "number"
+            buffer.append(c)
+        elif c in ["+", "-", "*", "/", "(", ")"]:
+            if buffer:
+                yield Integer.create_from_string(_take_buffer())
+                prediction = None
+            match c:
+                case "+" | "-":
+                    yield Operator(c, precedence=1)
+                case "*" | "/":
+                    yield Operator(c, precedence=2)
+                case _:
+                    yield Parenthesis(c) # type: ignore
+            prediction = None
+        elif c == " ":
+            pass
+        else:
+            raise SyntaxError()
+    if buffer:
+        yield Integer.create_from_string(_take_buffer())