/// <summary>
/// if statement ( including if...then && if...goto )
/// </summary>
/// <returns></returns>
protected Statement ifStatement()
{
Statement ifS = new Statement(Statement.TYPE_IF);
eatToken(Token.IF);
ifS.m_expressList = new List <Expression>();
ifS.m_statements = new List <Statement>();
ifS.m_expressList.Add(expression());
int tt = lookAhead();
if (tt != Token.THEN && tt != Token.GOTO)
{
throw new ErrorCode(ErrorCode.ERROR_CODE_02);
}
eatToken(tt);
Token tok = null;
List <Statement> s = new List <Statement>();
Statement ss = null;
if (lookAhead() == Token.INT)
{
tok = eatToken(Token.INT);
ss = new Statement(Statement.TYPE_GOTO);
ss.m_intVal = tok.m_intVal;
s.Add(ss);
}
else
{
if (tt == Token.GOTO)
{
throw new ErrorCode(ErrorCode.ERROR_CODE_02);
}
s = statements();
}
ifS.m_statements = s;
// else case
if (lookAhead() == Token.ELSE)
{
eatToken(Token.ELSE);
s = new List <Statement>();
if (lookAhead() == Token.INT)
{
tok = eatToken(Token.INT);
ss = new Statement(Statement.TYPE_GOTO);
ss.m_intVal = tok.m_intVal;
s.Add(ss);
}
else
{
s = statements();
}
ifS.m_elseStatements = s;
}
else
{
ifS.m_elseStatements = new List <Statement>();
}
return(ifS);
}
protected Expression expression7()
{
Expression exp = null;
int tt = lookAhead();
Token tok = null;
if (tt == Token.SYMBOL)
{
if (lookAhead(1) == Token.LEFT_PAREN)
{
// array
exp = new Expression(Expression.EXP_ARRAY_SYMBOL);
tok = eatToken(Token.SYMBOL);
exp.m_symbolName = tok.m_strVal;
eatToken(Token.LEFT_PAREN);
exp.m_funcParams = expressList();
eatToken(Token.RIGHT_PAREN);
}
else
{
exp = new Expression(Expression.EXP_SYMBOL);
tok = eatToken(Token.SYMBOL);
exp.m_symbolName = tok.m_strVal;
}
}
else if (tt == Token.INT)
{
tok = eatToken(Token.INT);
exp = new Expression(new BaseData(tok.m_intVal));
}
else if (tt == Token.FLOAT)
{
tok = eatToken(Token.FLOAT);
exp = new Expression(new BaseData(tok.m_floatVal));
}
else if (tt == Token.LEFT_PAREN)
{
eatToken(Token.LEFT_PAREN);
exp = expression();
eatToken(Token.RIGHT_PAREN);
}
else if (tt == Token.MINUS)
{
exp = new Expression(Expression.OP_NEG);
eatToken(Token.MINUS);
exp.m_leftExp = expression7();
}
else if (tt == Token.FUNC)
{
exp = new Expression(Expression.EXP_FUNC);
exp.m_funcParams = new List <Expression>();
// function name
tok = eatToken(Token.FUNC);
exp.m_symbolName = tok.m_strVal;
// function parameters
eatToken(Token.LEFT_PAREN);
exp.m_funcParams.Add(expression());
while (lookAhead() == Token.COMMA)
{
eatToken(Token.COMMA);
exp.m_funcParams.Add(expression());
}
eatToken(Token.RIGHT_PAREN);
}
else if (tt == Token.STRING)
{
tok = eatToken(Token.STRING);
exp = new Expression(new BaseData(tok.m_strVal));
}
else if (tt == Token.FN)
{
exp = new Expression(Expression.EXP_USER_FUNC);
eatToken(Token.FN);
tok = eatToken(Token.SYMBOL);
exp.m_symbolName = tok.m_strVal;
eatToken(Token.LEFT_PAREN);
exp.m_funcParams = new List <Expression>();
exp.m_funcParams.Add(expression());
eatToken(Token.RIGHT_PAREN);
}
else if (tt == Token.INKEY)
{
exp = new Expression(Expression.EXP_INKEY);
eatToken(Token.INKEY);
}
else
{
throw new ErrorCode(ErrorCode.ERROR_CODE_02);
}
return(exp);
}