def visit_IF(self, node):
expr_ = (yield ToVisit(node.children[0]))
then_ = (yield ToVisit(node.children[1]))
else_ = (yield ToVisit(node.children[2])) if len(node.children) == 3 else self.NOP
if self.O_LEVEL >= 1:
if chk.is_null(then_, else_):
src.api.errmsg.warning_empty_if(node.lineno)
yield self.NOP
return
block_accessed = chk.is_block_accessed(then_) or chk.is_block_accessed(else_)
if not block_accessed and chk.is_number(expr_): # constant condition
if expr_.value: # always true (then_)
yield then_
else: # always false (else_)
yield else_
return
if chk.is_null(else_) and len(node.children) == 3:
node.children.pop() # remove empty else
yield node
return
for i in range(len(node.children)):
node.children[i] = (expr_, then_, else_)[i]
yield node
def visit_WHILE(self, node):
expr_ = (yield node.children[0])
body_ = (yield node.children[1])
if self.O_LEVEL >= 1:
if chk.is_number(expr_) and not expr_.value and not chk.is_block_accessed(body_):
yield self.NOP
return
for i, child in enumerate((expr_, body_)):
node.children[i] = child
yield node
def visit_FOR(self, node):
from_ = (yield node.children[1])
to_ = (yield node.children[2])
step_ = (yield node.children[3])
body_ = (yield node.children[4])
if self.O_LEVEL > 0 and chk.is_number(from_, to_, step_) and not chk.is_block_accessed(body_):
if from_ > to_ and step_ > 0:
yield self.NOP
return
if from_ < to_ and step_ < 0:
yield self.NOP
return
for i, child in enumerate((from_, to_, step_, body_), start=1):
node.children[i] = child
yield node