def find_source_table(expr):
# A more complex version of _find_base_table.
# TODO: Revisit/refactor this all at some point
node = expr.op()
# First table expression observed for each argument that the expr
# depends on
first_tables = []
def push_first(arg):
if not isinstance(arg, ir.Expr):
return
if isinstance(arg, ir.TableExpr):
first_tables.append(arg)
else:
collect(arg.op())
def collect(node):
for arg in node.flat_args():
push_first(arg)
collect(node)
options = util.unique_by_key(first_tables, id)
if len(options) > 1:
raise NotImplementedError
return options[0]
def find_backend(expr):
from ibis.client import Client
backends = []
def walk(expr):
node = expr.op()
for arg in node.flat_args():
if isinstance(arg, Client):
backends.append(arg)
elif isinstance(arg, ir.Expr):
walk(arg)
walk(expr)
backends = util.unique_by_key(backends, id)
if len(backends) > 1:
raise ValueError('Multiple backends found')
return backends[0]
def find_backend(expr):
backends = []
def walk(expr):
node = expr.op()
for arg in node.flat_args():
if isinstance(arg, Client):
backends.append(arg)
elif isinstance(arg, ir.Expr):
walk(arg)
walk(expr)
backends = util.unique_by_key(backends, id)
if len(backends) > 1:
raise ValueError('Multiple backends found')
elif len(backends) == 0:
default = options.default_backend
if default is None:
raise com.IbisError('Expression depends on no backends, '
'and found no default')
return default
return backends[0]
def distinct_roots(*args):
all_roots = []
for arg in args:
all_roots.extend(arg._root_tables())
return util.unique_by_key(all_roots, id)
def distinct_roots(*args):
all_roots = []
for arg in args:
all_roots.extend(arg._root_tables())
return util.unique_by_key(all_roots, id)
