BUG: prevent certain index types from joining with DatetimeIndex
CLN: remove engine detection and manip for datetimes
ENH: allow an already-parsed expression to be passed to eval
DOC: add docstring to eval
API: expose the computation.expr.Expr object to top level pandas
ENH: rewrite assignment as equal comparison
ENH: add Expr based terms for pytables
ENH: allow multiple warnings to be checked in assert_produces_warning
ENH: handle Indexes in alignment
ENH: add automatic query via frame.__getitem__
DOC: add API docs
DOC: add query docstring
DOC: use float index for now in query docs
PERF: add start of vbench for eval
ENH: add boolean operators
ENH: add chained comparisons