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);
}
public DeclarationsNode Declarations()
{
var declarations = new DeclarationsNode();
while (token.value == "var")
{
Match(TokenTypes.ID, "var");
VarTypes type = VarTypes.NONE;
var tempList = new List <string>();//holds the names of declared variables
Match(TokenTypes.ID);
tempList.Add(returnToken.value);
while (token.value == ",")
{
Match(TokenTypes.COMMA);
Match(TokenTypes.ID);
tempList.Add(returnToken.value);
}
Match(TokenTypes.COLON);
if (token.value == "array")//if its an array
{
Match(TokenTypes.ID, "array");
Match(TokenTypes.LBRACKET);
Match(TokenTypes.NUM);
int startIndex = int.Parse(returnToken.value);
Match(TokenTypes.COLON);
Match(TokenTypes.NUM);
int endIndex = int.Parse(returnToken.value);
Match(TokenTypes.RBRACKET);
Match(TokenTypes.ID, "of");
if (token.value == "integer")
{
type = VarTypes.INT;
}
else if (token.value == "real")
{
type = VarTypes.REAL;
}
Match(TokenTypes.ID);
foreach (var name in tempList)
{
var var = new ArrayVariableNode(name, type, startIndex, endIndex);
declarations.variableList.Add(var);
}
}
else//if its not an array
{
if (token.value == "integer")
{
type = VarTypes.INT;
}
else if (token.value == "real")
{
type = VarTypes.REAL;
}
Match(TokenTypes.ID);
foreach (var name in tempList)
{
var vari = new VariableNode(name, type);
declarations.variableList.Add(vari);
}
}
Match(TokenTypes.SEMICOLON);
}
return(declarations);
}
public SubProgramNode SubProgram()
{
SubProgramNode subProgramNode = new SubProgramNode();
Match(TokenTypes.ID);
subProgramNode.id = returnToken.value;
if (token.value == "(")
{
bool end;
Match(TokenTypes.LPAR);
do
{
VarTypes type = VarTypes.NONE;
var tempList = new List <string>();//holds the names of declared variables
Match(TokenTypes.ID);
tempList.Add(returnToken.value);
while (token.value == ",")
{
Match(TokenTypes.COMMA);
Match(TokenTypes.ID);
tempList.Add(returnToken.value);
}
Match(TokenTypes.COLON);
if (token.value == "array")//if its an array
{
Match(TokenTypes.ID, "array");
Match(TokenTypes.LBRACKET);
Match(TokenTypes.NUM);
int startIndex = int.Parse(returnToken.value);
Match(TokenTypes.COLON);
Match(TokenTypes.NUM);
int endIndex = int.Parse(returnToken.value);
Match(TokenTypes.RBRACKET);
Match(TokenTypes.ID, "of");
if (token.value == "integer")
{
type = VarTypes.INT;
}
else if (token.value == "real")
{
type = VarTypes.REAL;
}
Match(TokenTypes.ID);
foreach (var name in tempList)
{
var var = new ArrayVariableNode(name, type, startIndex, endIndex);
subProgramNode.argumentList.Add(var);
}
}
else//if its not an array
{
if (token.value == "integer")
{
type = VarTypes.INT;
}
else if (token.value == "real")
{
type = VarTypes.REAL;
}
Match(TokenTypes.ID);
foreach (var name in tempList)
{
var vari = new VariableNode(name, type);
subProgramNode.argumentList.Add(vari);
}
}
end = token.value == ")";
if (!end)
{
Match(TokenTypes.SEMICOLON);
}
} while (!end);
Match(TokenTypes.RPAR);
if (token.value == ":")
{
Match(TokenTypes.COLON);
Match(TokenTypes.ID);
subProgramNode.type = returnToken.value;
}
Match(TokenTypes.SEMICOLON);
}
subProgramNode.declarations = Declarations();
SubProgramDeclarations(subProgramNode.methodList);
CompoundStatement(subProgramNode.statementList);
return(subProgramNode);
}