source: add IRLocation type specifically for generated IR

compiler/source.py

@@ -138,3 +138,46 @@ class SourceLocation:
             result[i] = "\n".join(lines)
 
         return "\n".join(result)
+
+
+@typecheck
+class IRLocation:
+    def __init__(self, line: int = -1, ir: list[str] = None):
+        if ir is None:
+            ir = []
+
+        self.line = line
+        self.ir = ir
+
+    @typecheck
+    def __lt__(self, other: IRLocation):
+        assert self.line >= 0
+
+        return self.line < other.line
+
+    @typecheck
+    def __ge__(self, other: IRLocation):
+        assert self.line >= 0
+
+        return self.line >= other.line
+
+    @typecheck
+    def __eq__(self, other: IRLocation):
+        assert self.line >= 0
+
+        return self.line == other.line
+
+    def __str__(self) -> str:
+        assert self.line >= 0
+        assert len(self.ir) > self.line
+
+        repr_len = int(math.log10(len(self.ir)) + 1)
+
+        messages = []
+        messages += self.ir[self.line - 2:self.line + 1]
+        messages += ["^" * len(self.ir[self.line])]
+        messages += self.ir[self.line:self.line + 3]
+
+        messages = [f"{str(self.line + i - 2).zfill(repr_len)}: {m}" for i, m in enumerate(messages)]
+
+        return "\n".join(messages)