algebra.py 文件源码

def _aggs(e, A):
    """
    Collect Aggregates in A
    replaces aggregates with variable references
    """

    # TODO: nested Aggregates?

    if isinstance(e, CompValue) and e.name.startswith('Aggregate_'):
        A.append(e)
        aggvar = Variable('__agg_%d__' % len(A))
        e["res"] = aggvar
        return aggvar