def computeStatement(self, constraint_collection):
outer_constraint_collection = constraint_collection
constraint_collection = ConstraintCollectionBranch(
parent = constraint_collection,
name = "loop"
)
loop_body, break_collections = self.computeLoopBody(constraint_collection)
# Consider trailing "continue" statements, these have no effect, so we
# can remove them.
if loop_body is not None:
assert loop_body.isStatementsSequence()
statements = loop_body.getStatements()
assert statements # Cannot be empty
# If the last statement is a "continue" statement, it can simply
# be discarded.
last_statement = statements[-1]
if last_statement.isStatementContinueLoop():
if len(statements) == 1:
self.setLoopBody(None)
loop_body = None
else:
last_statement.replaceWith(None)
constraint_collection.signalChange(
"new_statements",
last_statement.getSourceReference(),
"""\
Removed useless terminal 'continue' as last statement of loop."""
)
if break_collections:
outer_constraint_collection.mergeMultipleBranches(break_collections)
# Consider leading "break" statements, they should be the only, and
# should lead to removing the whole loop statement. Trailing "break"
# statements could also be handled, but that would need to consider if
# there are other "break" statements too. Numbering loop exits is
# nothing we have yet.
if loop_body is not None:
assert loop_body.isStatementsSequence()
statements = loop_body.getStatements()
assert statements # Cannot be empty
if len(statements) == 1 and statements[-1].isStatementBreakLoop():
return None, "new_statements", """\
Removed useless loop with immediate 'break' statement."""
# Also consider the threading intermission. TODO: We ought to make it
# explicit, so we can see it potentially disrupting and changing the
# global variables. It may also raise.
outer_constraint_collection.onExceptionRaiseExit(BaseException)
return self, None, None
