# LDC-E0104 — An escape the string does not define

## What it means

Inside a quoted string, a backslash starts an escape: a short code for a
character that is hard to type directly. Only the escapes the language
defines are allowed. Any other letter after the backslash is not a
character with a typo — it is a request the string cannot honor, and the
string is rejected at that spot.

The fix is one character: replace the unknown escape with a defined one, or
drop the backslash if a plain character was meant. The rest of the string
stays untouched.

## Example

```law
language "law.core" version "0.2";
package probe.e4 version "0.1.0";
namespace "urn:law:probe:\q";
```

## Fix

```law
language "law.core" version "0.2";
package demo.diagnostics version "0.1.0";
namespace "urn:law:demo:diagnostics";
```

## Engine message

The engine reports this in its own wording:

```text
example.law:3:26: error LDC-E0104: invalid escape sequence in string (§17)
```

## Related

- [LDC-E0102](/diagnostics/LDC-E0102/) — a string the reader cannot close.