public InterpreterResult Visit(VarAssignmentNode node, Context context)
{
if (!context.SymbolTable.IsDefined(node.VarNameTok.Value))
{
return(new InterpreterResult(null, new RuntimeError($"{node.VarNameTok.Value} is not defined", node.VarNameTok.Pos_Start, node.VarNameTok.Pos_End, context)));
}
var result = Visit(node.ValueNode, context);
if (result.Error != null)
{
return(result.Error);
}
context.SymbolTable[node.VarNameTok.Value] = result.Result;
return(result);
}
private ParseResult ForExpr()
{
var start = current_token.Pos_Start.Copy();
Advance();
Node initNode = null;
if (current_token.Type == TokenType.INDENTIFIER)
{
Token idToken = current_token;
Advance();
if (current_token.Equals(TokenType.EQ))
{
Advance();
var expr = Expr();
if (expr.HasError())
{
return(expr);
}
initNode = new VarAssignmentNode(idToken, expr.Node).SetPos(idToken.Pos_Start, idToken.Pos_End);
}
}
else if (current_token.Equals(new Token(TokenType.KEYWORD, "var")))
{
var declarationResult = GetVarDeclaration();
if (declarationResult.HasError())
{
return(declarationResult);
}
initNode = declarationResult.Node;
}
else
{
return(new InvalidSyntaxError("Expected identifier or var", current_token.Pos_Start, current_token.Pos_End));
}
if (!current_token.Equals(new Token(TokenType.KEYWORD, "to")))
{
return(new InvalidSyntaxError("Expected 'to'", current_token.Pos_Start, current_token.Pos_End));
}
Advance();
var endResult = Expr();
if (endResult.HasError())
{
return(endResult);
}
ParseResult stepResult = null;
if (current_token.Equals(new Token(TokenType.KEYWORD, "step")))
{
Advance();
stepResult = Expr();
if (stepResult.HasError())
{
return(stepResult);
}
}
if (!current_token.Equals(new Token(TokenType.KEYWORD, "then")))
{
return(new InvalidSyntaxError("Expected 'then'", current_token.Pos_Start, current_token.Pos_End));
}
Advance();
var bodyResult = Expr();
if (bodyResult.HasError())
{
return(bodyResult);
}
return(new ForNode(initNode, endResult.Node, stepResult?.Node, bodyResult.Node).SetPos(start, current_token.Pos_End));
}
