public void CopyValueFromNode(EnviromentNode node)
{
this.delayEvalBlock = node.delayEvalBlock;
this.svalue = node.svalue;
this.ivalue = node.ivalue;
this.dvalue = node.dvalue;
this.valueType = node.valueType;
}
public void ClearDelayEvalBlock()
{
delayEvalBlock = null;
}
public void AddDelayEvalBlock(DelayEvalBlock block)
{
delayEvalBlock = new DelayEvalBlock(block.Node, block.Enviroment);
}
public EnviromentNode(Enviroment env)
{
enviroment = new Enviroment(env);
terminate = false;
this.delayEvalBlock = null;
this.valueType = "unknow";
}
private static void EvalVarSentense(ParseNode node, Enviroment enviroment,
EnviromentNode envNode)
{
envNode.Symbol = node.Nodes[1].Token.Text;
if (node.Nodes[2].Token.Type == TokenType.FUNCTION)
{
EnviromentNode resultNode = EvalDirectFunctionCall(node.Nodes[2], enviroment, envNode.Enviroment);
// before bind function result to a smbol, eval result node first
EvalDelayEvalBlock(resultNode);
if (resultNode.GrammerNode != null)
{
ParseNode result = resultNode.GrammerNode;
if (resultNode.ValueType != "lambda")
{
envNode.Type = GetTypeString(result.Nodes[2], null);
envNode.Value = GetValueOfLambda(result.Nodes[2]);
}
envNode.GrammerNode = result;
}
envNode.Enviroment = resultNode.Enviroment;
envNode.CopyValueFromNode(resultNode);
return;
}
else if (node.Nodes[2].Token.Type == TokenType.IFTHENELSE)
{
DelayEvalBlock block = new DelayEvalBlock(node.Nodes[2], enviroment);
envNode.AddDelayEvalBlock(block);
EvalDelayEvalBlock(envNode);
}
else if (node.Nodes[2].Token.Type == TokenType.LAMBDA)
{
envNode.GrammerNode = node;
envNode.Type = GetTypeString(node.Nodes[2], null);
envNode.Value = GetValueOfLambda(node.Nodes[2]);
envNode.ValueType = "lambda";
}
else if (node.Nodes[2].Token.Type == TokenType.DIGIT)
{
envNode.GrammerNode = null;
envNode.ValueType = "int";
envNode.IValue = Int32.Parse(node.Nodes[2].Token.Text);
}
else if (node.Nodes[2].Token.Type == TokenType.STRINGVAL)
{
envNode.GrammerNode = null;
envNode.ValueType = "string";
string tmp = node.Nodes[2].Token.Text;
envNode.SValue = tmp.Substring(1, tmp.Length - 2);
}
}
/*
* eval sentense like " AND TRUE FALSE"
* parameters can be another function call, like AND (AND TRUE TRUE) FALSE
* currently eval all parameters before apply to functor
* if parameter ( and after eval function all ) does not exist in enviroment, just leave a symbol in it
* in order to support IO, add special functor type __io__, which evals special, need to do IOs internally
* and in order to support function, add special functor type __function__
* when eval __function__, eval sentenses inside this function until we met a "return"
* if a lambda like \(x,y).x , say only one element in body, it's a terminal symbol
* else treate first elememt in body as a functor and eval it
*/
private static EnviromentNode EvalDirectFunctionCall(ParseNode node, Enviroment enviroment, Enviroment closure)
{
// nodes[0] == 'var'
// nodes[1] == symbol
// nodes[2] == function body
if (node.Nodes.Count < 1)
throw new Exception("invalid direct function call");
ParseNode funcBody = node;
string lambdaSymbol = funcBody.Nodes[0].Token.Text;
EnviromentNode funcNode = closure.LookupSymbol(lambdaSymbol);
if (funcNode == null)
funcNode = enviroment.LookupSymbol(lambdaSymbol);
// before apply parameters to a lambda, eval functor to get a result
EvalDelayEvalBlock(funcNode);
/*
* sentense like
* var a = \(x,y).x TRUE FALSE
* FIXME
*/
EnviromentNode[] parameters = new EnviromentNode[funcBody.Nodes.Count - 1];
for (int index = 1; index < funcBody.Nodes.Count; index++)
{
ParseNode paramNode = funcBody.Nodes[index];
if (paramNode.Token.Type == TokenType.FUNCTION || paramNode.Token.Type == TokenType.IFTHENELSE )
{
// parameters[index - 1] = EvalDirectFunctionCall(funcBody.Nodes[index], enviroment, null);
DelayEvalBlock block = new DelayEvalBlock(funcBody.Nodes[index], enviroment);
parameters[index - 1] = new EnviromentNode(enviroment);
parameters[index - 1].AddDelayEvalBlock(block);
}
else
{
Token token = funcBody.Nodes[index].Token;
EnviromentNode tmp = null;
if (token.Type == TokenType.DIGIT)
{
// like foo 12;
tmp = new EnviromentNode(enviroment);
tmp.IValue = Int32.Parse(token.Text);
tmp.ValueType = "int";
}
else if (token.Type == TokenType.STRINGVAL)
{
// like foo "hello";
tmp = new EnviromentNode(enviroment);
tmp.SValue = token.Text.Substring(1, token.Text.Length - 2);
tmp.ValueType = "string";
}
else if (token.Type == TokenType.LAMBDA)
{
/*
* sentense like
* return \(x,y).x
* foo \(x,y).x FALSE
*/
tmp = new EnviromentNode(enviroment);
tmp.Type = GetTypeString(funcBody.Nodes[index], null);
tmp.Value = GetValueOfLambda(funcBody.Nodes[index]);
tmp.GrammerNode = funcBody.Nodes[index];
tmp.ValueType = "lambda";
}
else
{
// like foo a b;
tmp = enviroment.LookupSymbol(token.Text);
if (tmp == null)
{
tmp = new EnviromentNode(null);
tmp.Symbol = token.Text;
}
}
parameters[index - 1] = tmp;
}
}
EnviromentNode result = null;
if (funcNode.Type == "__io__")
{
result = ApplyIO(funcNode, parameters, enviroment);
}
else if (funcNode.Type == "__function__")
{
result = ApplyFunction(funcNode, parameters, enviroment);
}
else if (funcNode.Type == "__buildin__")
{
result = ApplyBuildinFunction(funcNode, parameters, enviroment);
}
else // lambda
{
if (parameters.Length == 0)
{
result = closure.LookupSymbol(lambdaSymbol);
if (result == null)
result = enviroment.LookupSymbol(lambdaSymbol);
}
else
result = ApplyToLambda(lambdaSymbol, parameters, enviroment, funcNode.Enviroment);
}
return result;
}