Add support for OPTIONAL.
Report a syntax error if the query is invalid.
Add support for less than and greater than filters.
Add support for BOUND expressions.
Add support for basic arithmetic expressions.
Add support for DESCRIBE queries.
Add support for literal comparisons.
Add support for LANG and LANGMATCHES.
Add support for REGEX.
Add support for ORDER BY.
Add support for OFFSET and LIMIT.
Use SPARQL names of operators.
Make casts operators.
Release version 0.1.2 of the npm package.