Generally, if you make a mistake in a DIESEL expression, what went wrong may not be obvious. Depending on the nature of the error, DIESEL embeds an error indication in the output stream.
| DIESEL error messages |
|---|
| Error message | Description |
|---|
| $? | Syntax error (usually a missing right parenthesis or a runaway string) |
| $(func,??) | Incorrect arguments to func |
| $(func)?? | Unknown function func |
| $(++) | Output string too long—evaluation truncated |