# pylint:disable=unused-argument,arguments-differ
import ailment
from ..sequence_walker import SequenceWalker
from ..structuring.structurer_nodes import (
SequenceNode,
CodeNode,
MultiNode,
LoopNode,
ConditionNode,
CascadingConditionNode,
)
from ..utils import is_empty_node
[docs]class CascadingIfsRemover(SequenceWalker):
"""
Coalesce cascading If constructs. Transforming the following construct::
if (cond_a) {
if (cond_b) {
true_body
} else { }
} else { }
into::
if (cond_a and cond_b) {
true_body
} else { }
"""
[docs] def __init__(self, node):
handlers = {
SequenceNode: self._handle_Sequence,
CodeNode: self._handle_Code,
MultiNode: self._handle_MultiNode,
LoopNode: self._handle_Loop,
ConditionNode: self._handle_Condition,
CascadingConditionNode: self._handle_CascadingCondition,
}
super().__init__(handlers)
self.walk(node)
def _handle_Condition(self, node, parent=None, index=None, **kwargs):
"""
:param ConditionNode node:
:param successor:
:return:
"""
if node.true_node is not None:
self._handle(node.true_node, parent=node, index=0)
if node.false_node is not None:
self._handle(node.false_node, parent=node, index=1)
if node.true_node is not None and node.false_node is None:
if isinstance(node.true_node, SequenceNode):
last_node = None
if len(node.true_node.nodes) > 1 and all(is_empty_node(node_) for node_ in node.true_node.nodes[:-1]):
last_node = node.true_node.nodes[-1]
elif len(node.true_node.nodes) == 1:
last_node = node.true_node.nodes[0]
true_node = last_node
elif isinstance(node.true_node, ConditionNode):
true_node = node.true_node
else:
return
if (
isinstance(true_node, ConditionNode)
and true_node.true_node is not None
and true_node.false_node is None
):
node.condition = ailment.BinaryOp(
None, "LogicalAnd", (node.condition, true_node.condition), False, **node.condition.tags
)
node.true_node = true_node.true_node