private string ReadStatement(ReadStatementNode node)
{
string output = "";
return(output);
}
public StatementNode Statement()
{
StatementNode statementNode = null;
if (token.value == "if")
{
var ifStatementNode = new IfThenStatementNode();
Match(TokenTypes.ID, "if");
ifStatementNode.ifExpression = Expression();
Match(TokenTypes.ID, "then");
ifStatementNode.thenStatement = Statement();
Match(TokenTypes.ID, "else");
ifStatementNode.elseStatement = Statement();
statementNode = ifStatementNode;
}
else if (token.value == "while")
{
var whileStatementNode = new WhileStatementNode();
Match(TokenTypes.ID, "while");
whileStatementNode.whileExpression = Expression();
Match(TokenTypes.ID, "do");
whileStatementNode.doStatement = Statement();
statementNode = whileStatementNode;
}
else if (token.value == "begin")
{
var statementList = new List <StatementNode>();
CompoundStatement(statementList);
}
else if (token.value == "read")
{
Match(TokenTypes.ID, "read");
Match(TokenTypes.LPAR);
Match(TokenTypes.ID);
var readStatementNode = new ReadStatementNode(returnToken.value);
Match(TokenTypes.RPAR);
statementNode = readStatementNode;
}
else if (token.value == "write")
{
Match(TokenTypes.ID, "write");
Match(TokenTypes.LPAR);
var writeStatementNode = new WriteStatementNode();
writeStatementNode.expression = Expression();
Match(TokenTypes.RPAR);
statementNode = writeStatementNode;
}
//else if(nextToken.type==TokenTypes.ASSIGNOP)
else
{
Match(TokenTypes.ID);
string id = returnToken.value;
bool array = false;
var index = new ExpressionNode(); //for use in array assignops
var expressionList = new List <ExpressionNode>(); //for use in procedure statement
if (token.value == "[")
{
Match(TokenTypes.LBRACKET);
index = Expression();
Match(TokenTypes.RBRACKET);
array = true;
}
else if (token.value == "(")
{
Match(TokenTypes.LPAR);
do
{
expressionList.Add(Expression());
} while (token.value == ",");
Match(TokenTypes.RPAR);
}
if (token.type == TokenTypes.ASSIGNOP)//assignop statement
{
var assignStatementNode = new AssignOpStatementNode();
int i = 0;
while (program.Declarations.variableList[i].variableName != id)
{
i++;
if (i > program.Declarations.variableList.Count)
{
throw new Exception("");
}
}
if (array)
{
ArrayVariableNode tempArrayVar = program.Declarations.variableList[i] as ArrayVariableNode;
if (tempArrayVar == null)
{
throw new Exception("");
}
assignStatementNode.variable = new ArrayVariableNode(id, program.Declarations.variableList[i].type, tempArrayVar.startIndex, tempArrayVar.endIndex);
assignStatementNode.arrayExpression = index;
}
else
{
assignStatementNode.variable = new VariableNode(id, program.Declarations.variableList[i].type);
}
Match(TokenTypes.ASSIGNOP);
assignStatementNode.expression = Expression();
statementNode = assignStatementNode;
}
else//procedure statement
{
var procedureStatementNode = new ProcedureStatementNode();
procedureStatementNode.id = id;
procedureStatementNode.expressionList = expressionList;
statementNode = procedureStatementNode;
}
}
return(statementNode);
}