Function validate_ident 

pub fn validate_ident(name: &str) -> Result<&str, SqlError>

Validates that name is a non-empty identifier without control characters.

Returns the input on success so the call composes inside iterator chains (e.g. Option::map(validate_ident).transpose()?).

Errors

Returns SqlError::InvalidIdentifier if the name is empty, whitespace-only, or contains control characters.