Rendering code refactor

folkugat_web/model/lilypond/processing.py

@@ -0,0 +1,24 @@
+import dataclasses
+from typing import Self
+
+
+@dataclasses.dataclass
+class RenderError:
+    line: int
+    pos: int
+    error: str
+
+    @classmethod
+    def from_dict(cls, error_match: dict[str, str]) -> Self:
+        return cls(
+            line=int(error_match["line"]),
+            pos=int(error_match["pos"]),
+            error=error_match["error"],
+        )
+
+    def to_dict(self) -> dict[str, str]:
+        return dict(
+            line=str(self.line),
+            pos=str(self.pos),
+            error=self.error,
+        )