// Parse a DO WHILE loop construct
ParseNode KDoWhile(SymbolParseNode endLabelNode)
{
LoopParseNode node = new LoopParseNode();
ExpectToken(TokenID.KWHILE);
ExpectToken(TokenID.LPAREN);
node.StartExpression = Expression();
ExpectToken(TokenID.RPAREN);
ExpectEndOfLine();
node.LoopBody = ParseDoBody(endLabelNode);
if (node.StartExpression.IsConstant && !node.StartExpression.Value.BoolValue) {
_messages.Warning(MessageCode.LOOPSKIPPED, 2, "Loop will be skipped because the expression is false");
}
return node;
}
// Parse the body of a standard DO or DO WHILE loop.
CollectionParseNode ParseDoBody(SymbolParseNode endLabelNode)
{
CollectionParseNode statements = new CollectionParseNode();
bool loopDone = false;
SimpleToken token = _ls.GetKeyword();
++_blockDepth;
do {
ParseNode labelNode = CheckLabel();
if (labelNode != null) {
statements.Add(labelNode);
}
if (token.ID == TokenID.KENDDO) {
_messages.Warning(MessageCode.NONSTANDARDENDDO, 4, "Use of ENDDO is non-standard");
loopDone = true;
break;
}
statements.Add(MarkLine());
ParseNode subnode = Statement(token);
if (subnode != null) {
statements.Add(subnode);
}
if (_ls.HasLabel && endLabelNode != null && _ls.Label == endLabelNode.Symbol.Name) {
loopDone = true;
break;
}
ExpectEndOfLine();
token = _ls.GetKeyword();
} while (token.ID != TokenID.ENDOFFILE);
--_blockDepth;
if (!loopDone) {
_messages.Error(MessageCode.MISSINGDOENDLABEL, "End label for DO loop not found");
}
return statements;
}