# Errors

tomlrt raises `TOMLParseError` for invalid input and `TOMLError` for operations that a document's structure does not allow. Ordinary lookups also raise `KeyError`, `IndexError`, and `TypeError` as appropriate.

## `TOMLError`

Base class for tomlrt's own errors. For example, converting a non-inline table to a section raises `TOMLError`.

```python
try:
    doc.table("project").promote_inline("authors")
except tomlrt.TOMLError as exc:
    log.warning("could not promote: %s", exc)
```

## `TOMLParseError`

Raised by `loads` / `load` when the input isn't valid TOML. Carries useful position information:

```python
import tomlrt

try:
    tomlrt.loads("a = ?")
except tomlrt.TOMLParseError as exc:
    print(f"line: {exc.line}, column: {exc.col}, offset: {exc.offset}")
```

```text
line: 1, column: 5, offset: 4
```

| Attribute | Meaning |
| --- | --- |
| `line` | 1-based line number |
| `col` | 1-based column number |
| `offset` | 0-based character offset into the source string |

Printing the exception includes the problem and its location:

```python
import tomlrt

try:
    tomlrt.loads("a = ?")
except tomlrt.TOMLParseError as exc:
    print(exc)
```

```text
invalid integer '?' (line 1, column 5)
```