// return null if this token isn't for this expression parser
public IExpression Parse(IParser parser, IStream <IToken> tokenStream, ref IParseError parseError)
{
IExpression declareExpression = null;
IList <IToken> tokens = new List <IToken>();
IToken token = tokenStream.Get(); // the first is the keyword
if ((token.Kind == TokenKind.UnquotedWord) && (token.Info == keywords.comment))
{
while ((token.Kind != TokenKind.NULL) && (!((token.Kind == TokenKind.UnquotedWord) && (token.Info == keywords.end))))
{
tokens.Add(token);
token = tokenStream.Get();
}
tokens.Add(token);
declareExpression = DeclareExpression.Create(parser, tokens, ref parseError);
}
else
{
tokenStream.Push(token);
}
return(declareExpression);
}
public DeclareExpression Build()
{
var expression = new DeclareExpression(_block);
var node = new DeclareOperator(_block);
while (_reader.HasNext())
{
_reader.Next();
var token = _reader.Current();
/*
* In this loop,tokens type can only be ',', 'identifer',';','='
* ',',';','=', requires previous token must be an Identifier
*
*/
if (token.TokenType == TokenType.Identifier)
{
node.Operands.Add(new OperandNode(new JString(token.Value)));
}
else if (token.OperatorType == OperatorType.Coma)//mutiple variable declaration
{
requirePreviousIsIdentifier();
continue;
}
else if (token.OperatorType == OperatorType.ExpressionEnd)//declaration ends
{
requirePreviousIsIdentifier();
node.DoCheck();
expression.Root = node;
return(expression);
}
else if (token.OperatorType == OperatorType.Assignment)// this expression is a declare-assignment expression
{
requirePreviousIsIdentifier();
var assign = new DeclareAsignmentNode(_block);
var astNode = new AstNodeBuilder(_reader, _block, _intercptChars).Build();
node.DoCheck();
assign.Operands = node.Operands;
assign.Operands.Add(astNode);
expression.Root = assign;
return(expression);
}
else
{
//invalid token type
throwError("");
}
}
// expression incomplete
throwError("");
return(null);
}