/// <summary>
/// Gets a VariableAST
/// </summary>
/// <returns>VariableAST</returns>
private AST Variable()
{
VariableAST ast = new VariableAST(this.currentToken);
this.ConsumeToken(TokenType.IDTOKEN);
return(ast);
}
public ForAST(Token token, StatementListAST ast, VariableAST variable, AST expression1, AST expression2) : base(token)
{
this.children = ast;
this.variable = variable;
this.expression1 = expression1;
this.expression2 = expression2;
}
/// <summary>
/// Gets a ReadAST
/// </summary>
/// <returns>ReadAST</returns>
private AST Read()
{
Token token = this.currentToken;
this.ConsumeToken(TokenType.READ);
VariableAST variable = this.Variable() as VariableAST;
return(new ReadAST(token, variable));
}
/// <summary>
/// Gets an assignment AST
/// </summary>
/// <returns>AssignmentAST</returns>
private AST Assignment()
{
VariableAST left = this.Variable() as VariableAST;
Token token = this.currentToken;
this.ConsumeToken(token.type);
AST right = this.Expression();
AssignAST ast = new AssignAST(left, this.currentToken, right);
return(ast);
}
/// <summary>
/// Gets a VariableDeclarationAST
/// </summary>
/// <returns>VariableDeclarationAST</returns>
private AST VariableDeclaration()
{
this.ConsumeToken(TokenType.VAR);
VariableAST variable = new VariableAST(this.currentToken);
this.ConsumeToken(TokenType.IDTOKEN);
this.ConsumeToken(TokenType.TWODOT);
TypeAST type = (TypeAST)this.TypeSpec();
if (this.currentToken.type == TokenType.SEMICOLON)
{
return(new VariableDeclarationAST(variable, type, this.currentToken));
}
else
{
this.ConsumeToken(TokenType.ASSIGN);
return(new VariableDeclarationAST(variable, type, this.currentToken, this.Expression()));
}
}
/// <summary>
/// Gets a ForAST
/// </summary>
/// <returns>ForAST</returns>
private AST For()
{
Token token = this.currentToken;
this.ConsumeToken(TokenType.FOR);
VariableAST variable = this.Variable() as VariableAST;
this.ConsumeToken(TokenType.IN);
AST expressionAST = this.Expression();
this.ConsumeToken(TokenType.TWO_CONCECUTIVE_DOTS);
AST expressionAST2 = this.Expression();
this.ConsumeToken(TokenType.DO);
StatementListAST ast = new StatementListAST();
this.StatementList().ForEach(x => ast.children.Add(x));
this.ConsumeToken(TokenType.END);
this.ConsumeToken(TokenType.FOR);
return(new ForAST(token, ast, variable, expressionAST, expressionAST2));
}
public AssignAST(VariableAST left, Token operation, AST right) : base(operation)
{
this.left = left;
this.right = right;
}
/// <summary>
/// Traverses variable AST
/// </summary>
/// <param name="ast">VariableAST</param>
/// <returns>Symbol value</returns>
private object VisitVariableAST(VariableAST ast)
{
string variableName = (string)ast.value;
return(this.symbolTable.LookupSymbol(variableName).value);
}
public ReadAST(Token token, VariableAST variable) : base(token)
{
this.variable = variable;
}
public VariableDeclarationAST(VariableAST varNode, TypeAST typeNode, Token token, AST assignValue = null) : base(token)
{
this.assignedValue = assignValue;
this.varNode = varNode;
this.typeNode = typeNode;
}