override public (string, object) Evaluate(SymbolTable symbolTable)
{
//get func node
FuncDec node = (FuncDec)symbolTable.GetFromMain((string)this.value).Item2;
//create the new symbol table for the new escope
SymbolTable inferiorST = new SymbolTable();
inferiorST.parent = symbolTable;
if (node.type != "none")
{
//create a var with the same name as the func to return
inferiorST.Set((string)node.value, null, node.type);
}
//get number of arguments
if (node.varList.Count != varList.Count)
{
throw new SystemException($"Function {node.value.ToString()} receives {node.varList.Count} arguments, but {varList.Count} where given. [Line: {Parser.CurrentLine}]");
}
Node[] valueNodeList = new Node[varList.Count];
int counter = 0;
foreach (Node n in varList)
{
valueNodeList[counter++] = n;
}
//dec vars and set values
counter = 0;
foreach (BinOp dec in node.varList)
{
dec.Evaluate(inferiorST);
(string, object)retVal = valueNodeList[counter++].Evaluate(symbolTable);
inferiorST.Set((string)dec.children[0].value, retVal.Item2, retVal.Item1);
}
//call function
node.children[0].Evaluate(inferiorST);
if (node.type == "none")
{
return("none", null);
}
//return the value by the name
return(inferiorST.Get(node.value.ToString()));
}
public static Node ParseFunction()
{
FuncDec root = new FuncDec();
bool sub = tokens.actual.type == "SUB";
if (sub)
{
Expect("SUB", true);
root.type = "none";
}
else
{
Expect("FUNCTION", true);;
}
Expect("IDENTIFIER", false);
root.value = tokens.actual.value;
tokens.SelectNext();
Expect("POPEN", true);
if (tokens.actual.type != "PCLOSE")
{
do
{
if (tokens.actual.type == "COMMA")
{
tokens.SelectNext();
}
Expect("IDENTIFIER", false);
BinOp dim = new BinOp();
dim.value = "vardec";
dim.children[0] = new NoOp();
dim.children[0].value = (string)tokens.actual.value;
tokens.SelectNext();
Expect("AS", true);
dim.children[1] = parseType();
root.Add(dim);
} while(tokens.actual.type == "COMMA");
}
Expect("PCLOSE", true);
if (!sub)
{
Expect("AS", true);
switch (tokens.actual.type)
{
case "INTEGER":
root.type = "integer";
break;
case "BOOLEAN":
root.type = "boolean";
break;
default:
throw new SystemException($"Expecting a VARTYPE token, got a {tokens.actual.type} (position {tokens.position}) [Line: {CurrentLine}]");
}
tokens.SelectNext();
}
Expect("LINEBREAK", true);
CurrentLine++;
root.children[0] = ParseStatements(sub ? "sub":"func");
if (sub)
{
Expect("SUB", true);
}
else
{
Expect("FUNCTION", true);
}
Expect("LINEBREAK", true);
CurrentLine++;
return(root);
}