//while_stmt: 'while' expression ':' suite ['else' ':' suite]
private WhileStatement ParseWhileStmt()
{
Eat(TokenKind.KeywordWhile);
string whileWhiteSpace = _tokenWhiteSpace;
var start = GetStart();
Expression expr = ParseExpression();
var mid = GetEnd();
Statement body = ParseLoopSuite();
Statement else_ = null;
string elseWhiteSpace = null;
int end = body.EndIndex;
if (MaybeEat(TokenKind.KeywordElse)) {
elseWhiteSpace = _tokenWhiteSpace;
else_ = ParseSuite();
end = else_.EndIndex;
}
WhileStatement ret = new WhileStatement(expr, body, else_);
ret.SetLoc(start, mid, end);
if (_verbatim) {
AddPreceedingWhiteSpace(ret, whileWhiteSpace);
if (elseWhiteSpace != null) {
AddSecondPreceedingWhiteSpace(ret, elseWhiteSpace);
}
}
return ret;
}
public override bool Walk(WhileStatement node)
{
UpdateChildRanges(node);
return base.Walk(node);
}
// WhileStmt
public override bool Walk(WhileStatement node)
{
// Walk the expression
node.Test.Walk(this);
BitArray opte = node.ElseStatement != null ? new BitArray(_bits) : null;
BitArray exit = new BitArray(_bits.Length, true);
PushLoop(exit);
node.Body.Walk(this);
PopLoop();
_bits.And(exit);
if (node.ElseStatement != null) {
// Flow the else
BitArray save = _bits;
_bits = opte;
node.ElseStatement.Walk(this);
// Restore the bits
_bits = save;
// Intersect
_bits.And(opte);
}
return false;
}
// WhileStatement
public override bool Walk(WhileStatement node)
{
return ShouldWalkWorker(node);
}
public override void PostWalk(WhileStatement node)
{
PostWalkWorker(node);
}
public override bool Walk(WhileStatement node)
{
WalkLoop(node.Body, node.ElseStatement);
return false;
}
public override bool Walk(WhileStatement node)
{
if (node.Test != null) {
node.Test.Walk(this);
}
if (node.Body != null) {
bool oldInLoop = _inLoop;
_inLoop = true;
node.Body.Walk(this);
_inLoop = oldInLoop;
}
if (node.ElseStatement != null) {
node.ElseStatement.Walk(this);
}
return false;
}
public override bool Walk(WhileStatement node)
{
return false;
}