|
public static CreateStatement ( |
||
| context | ||
| parent | IAstNode | |
| Результат | IStatement | |
/// <summary>
/// Abstract factory creating statements depending on current
/// token and the following token sequence
/// </summary>
/// <returns></returns>
public static IStatement Create(ParseContext context, IAstNode parent, string terminatingKeyword)
{
TokenStream <RToken> tokens = context.Tokens;
RToken currentToken = tokens.CurrentToken;
IStatement statement = null;
switch (currentToken.TokenType)
{
case RTokenType.Keyword:
// If statement starts with a keyword, it is not an assignment
// hence we should always try keyword based statements first.
// Some of the statements may be R-values like typeof() but
// in case of the statement appearing on its own return value
// will be simply ignored. IDE may choose to show a warning.
if (currentToken.SubType == RTokenSubType.BuiltinFunction && tokens.NextToken.TokenType != RTokenType.OpenBrace)
{
// 'return <- x + y' is allowed
statement = new ExpressionStatement(terminatingKeyword);
}
else
{
statement = KeywordStatement.CreateStatement(context, parent);
}
break;
case RTokenType.Semicolon:
statement = new EmptyStatement();
break;
default:
// Possible L-value in a left-hand assignment,
// a function call or R-value in a right hand assignment.
statement = new ExpressionStatement(terminatingKeyword);
break;
}
return(statement);
}
