private bool ParseListExpressionStep(ref LightList <ASTNode> retn)
{
while (true)
{
int commaIndex = tokenStream.FindNextIndexAtSameLevel(ExpressionTokenType.Comma);
if (commaIndex != -1)
{
ExpressionParser parser = CreateUndelimitedSubParser(commaIndex);
tokenStream.Advance();
bool valid = parser.ParseListExpressionStep(ref retn);
parser.Release();
if (!valid)
{
ReleaseList(retn);
return(false);
}
}
else
{
ASTNode node = ParseLoop();
if (node == null)
{
return(false);
}
retn.Add(node);
return(true);
}
}
}
private bool ParseTypeOfExpression(ref ASTNode retn)
{
if (tokenStream.Current != ExpressionTokenType.TypeOf || tokenStream.Next != ExpressionTokenType.ParenOpen)
{
return(false);
}
tokenStream.Advance();
int advance = tokenStream.FindMatchingIndex(ExpressionTokenType.ParenOpen, ExpressionTokenType.ParenClose);
if (advance == -1)
{
Abort();
return(false);
}
tokenStream.Save();
ExpressionParser subParser = CreateSubParser(advance);
TypeLookup typeLookup = new TypeLookup();
bool valid = subParser.ParseTypePath(ref typeLookup);
subParser.Release();
if (!valid)
{
Abort(); // hard fail since typeof token has no other paths to go
tokenStream.Restore();
return(false);
}
retn = ASTNode.TypeOfNode(typeLookup);
return(true);
}
private bool ParseTypePathGenerics(ref TypeLookup retn)
{
if (tokenStream.Current != ExpressionTokenType.LessThan)
{
return(false);
}
int advance = tokenStream.FindMatchingIndex(ExpressionTokenType.LessThan, ExpressionTokenType.GreaterThan);
if (advance == -1)
{
// Abort();
return(false);
}
tokenStream.Save();
ExpressionParser subParser = CreateSubParser(advance);
bool valid = subParser.ParseTypePathGenericStep(ref retn);
subParser.Release();
if (!valid)
{
Abort();
}
//tokenStream.Advance();
return(true);
}
private bool ParseParenExpression(ref ASTNode retn)
{
if (tokenStream.Current != ExpressionTokenType.ParenOpen)
{
return(false);
}
int advance = tokenStream.FindMatchingIndex(ExpressionTokenType.ParenOpen, ExpressionTokenType.ParenClose);
if (advance == -1)
{
throw new Exception("Unmatched paren"); // todo just abort
}
ExpressionParser subParser = CreateSubParser(advance);
retn = subParser.ParseLoop();
if (retn.IsCompound)
{
retn = ASTNode.ParenNode(retn);
}
ASTNode access = null;
if (ParseParenAccessExpression(ref access))
{
ParenNode parenNode = (ParenNode)retn;
parenNode.accessExpression = (MemberAccessExpressionNode)access;
}
subParser.Release();
return(true);
}
public static ASTNode Parse(TokenStream tokenStream)
{
ExpressionParser parser = new ExpressionParser(tokenStream);
ASTNode retn = parser.ParseLoop();
parser.Release();
return(retn);
}
public static bool ParseSignature(TokenStream tokenStream, StructList <LambdaArgument> signature)
{
ExpressionParser parser = new ExpressionParser(tokenStream);
bool retn = parser.ParseLambdaSignature(ref signature);
parser.Release();
if (!retn)
{
signature.Clear();
}
return(retn);
}
public static bool TryParseTypeName(string typeName, out TypeLookup typeLookup)
{
StructList <ExpressionToken> list = StructList <ExpressionToken> .Get();
ExpressionTokenizer.Tokenize(typeName, list);
ExpressionParser parser = new ExpressionParser(new TokenStream(list));
typeLookup = default;
bool valid = parser.ParseTypePath(ref typeLookup);
parser.Release();
list.Release();
return(valid);
}
private bool ParseAttribute(ref AttributeNode node)
{
if (tokenStream.Current != ExpressionTokenType.ArrayAccessOpen)
{
return(false);
}
tokenStream.Save();
tokenStream.Advance();
TypeLookup typeLookup = default;
ExpressionParser parser = new ExpressionParser(tokenStream);
if (!parser.ParseTypePath(ref typeLookup))
{
goto fail;
}
tokenStream.Set(parser.GetTokenPosition());
parser.Release(false);
if (tokenStream.Current == ExpressionTokenType.ArrayAccessClose)
{
tokenStream.Advance();
node = new AttributeNode()
{
typeLookup = typeLookup
};
return(true);
}
fail:
{
typeLookup.Release();
parser.Release(false);
return(false);
}
}
private bool ParseListExpression(ref LightList <ASTNode> retn, ExpressionTokenType openExpressionToken, ExpressionTokenType closeExpressionToken)
{
if (tokenStream.Current != openExpressionToken)
{
return(false);
}
int range = tokenStream.FindMatchingIndex(openExpressionToken, closeExpressionToken);
tokenStream.Save();
if (range == 1)
{
tokenStream.Advance(2);
retn = LightList <ASTNode> .Get();
return(true);
}
if (retn != null)
{
LightList <ASTNode> .Release(ref retn);
}
retn = LightList <ASTNode> .Get();
//todo find next comma at same level (meaning not inside [ or ( or <
ExpressionParser parser = CreateSubParser(range);
bool valid = parser.ParseListExpressionStep(ref retn);
parser.Release();
if (!valid)
{
tokenStream.Restore();
ReleaseList(retn);
return(false);
}
return(true);
}
// (int)something
private bool ParseDirectCastExpression(ref ASTNode retn)
{
if (tokenStream.Current != ExpressionTokenType.ParenOpen)
{
return(false);
}
ASTNode expression = null;
int advance = tokenStream.FindMatchingIndex(ExpressionTokenType.ParenOpen, ExpressionTokenType.ParenClose);
if (advance == -1)
{
Abort();
return(false);
}
tokenStream.Save();
ExpressionParser subParser = CreateSubParser(advance);
TypeLookup typeLookup = new TypeLookup();
bool valid = subParser.ParseTypePath(ref typeLookup);
subParser.Release();
if (!valid)
{
tokenStream.Restore();
return(false);
}
if (!ParseExpression(ref expression))
{
typeLookup.Release();
tokenStream.Restore();
tokenStream.Restore();
return(false);
}
retn = ASTNode.DirectCastNode(typeLookup, expression);
return(true);
}
// something.someValue
// something[i]
// something(*).x(*).y
private bool ParseAccessExpression(ref ASTNode retn)
{
if (tokenStream.Current != ExpressionTokenType.Identifier)
{
return(false);
}
string identifier = tokenStream.Current.value;
tokenStream.Save();
LightList <ASTNode> parts = LightList <ASTNode> .Get();
tokenStream.Advance();
while (tokenStream.HasMoreTokens)
{
if (tokenStream.Current == ExpressionTokenType.Dot || tokenStream.Current == ExpressionTokenType.Elvis)
{
if (tokenStream.Next != ExpressionTokenType.Identifier)
{
break;
}
tokenStream.Advance();
parts.Add(ASTNode.DotAccessNode(tokenStream.Current.value, tokenStream.Previous == ExpressionTokenType.Elvis));
tokenStream.Advance();
if (tokenStream.HasMoreTokens)
{
continue;
}
}
else if (tokenStream.Current == ExpressionTokenType.ArrayAccessOpen || tokenStream.Current == ExpressionTokenType.QuestionMark && tokenStream.NextTokenIs(ExpressionTokenType.ArrayAccessOpen))
{
bool isElvis = false;
if (tokenStream.Current == ExpressionTokenType.QuestionMark)
{
isElvis = true;
tokenStream.Advance();
}
int advance = tokenStream.FindMatchingIndex(ExpressionTokenType.ArrayAccessOpen, ExpressionTokenType.ArrayAccessClose);
if (advance == -1)
{
Abort("Unmatched array bracket");
}
ExpressionParser subParser = CreateSubParser(advance);
parts.Add(ASTNode.IndexExpressionNode(subParser.ParseLoop(), isElvis));
subParser.Release();
if (tokenStream.HasMoreTokens)
{
continue;
}
}
else if (tokenStream.Current == ExpressionTokenType.ParenOpen)
{
LightList <ASTNode> parameters = null;
if (!ParseListExpression(ref parameters, ExpressionTokenType.ParenOpen, ExpressionTokenType.ParenClose))
{
Abort();
}
parts.Add(ASTNode.InvokeNode(parameters));
if (tokenStream.HasMoreTokens)
{
continue;
}
}
else if (tokenStream.Current == ExpressionTokenType.LessThan)
{
// shortcut the << operator since we can't have a << in a generic type node. List<<string>> is invalid for example
if (tokenStream.HasMoreTokens && tokenStream.Next == ExpressionTokenType.LessThan)
{
tokenStream.Restore();
LightList <ASTNode> .Release(ref parts);
return(false);
}
TypeLookup typePath = new TypeLookup();
if (!(ParseTypePathGenerics(ref typePath)))
{
tokenStream.Restore();
LightList <ASTNode> .Release(ref parts);
return(false);
}
parts.Add(ASTNode.GenericTypePath(typePath));
if (tokenStream.HasMoreTokens)
{
continue;
}
}
if (parts.Count == 0)
{
tokenStream.Restore();
LightList <ASTNode> .Release(ref parts);
return(false);
}
retn = ASTNode.MemberAccessExpressionNode(identifier, parts).WithLocation(tokenStream.Peek());
return(true);
}
ReleaseList(parts);
tokenStream.Restore();
return(false);
}
private ASTNode ParseLoop()
{
while (tokenStream.HasMoreTokens)
{
ASTNode operand = default;
if (ParseExpression(ref operand))
{
if (tokenStream.Current == ExpressionTokenType.Increment)
{
tokenStream.Advance();
expressionStack.Push(ASTNode.UnaryExpressionNode(ASTNodeType.UnaryPostIncrement, operand));
}
else if (tokenStream.Current == ExpressionTokenType.Decrement)
{
tokenStream.Advance();
expressionStack.Push(ASTNode.UnaryExpressionNode(ASTNodeType.UnaryPostDecrement, operand));
}
else
{
expressionStack.Push(operand);
}
continue;
}
if (expressionStack.Count == 0)
{
Abort();
}
if (tokenStream.Current == ExpressionTokenType.QuestionMark && !tokenStream.NextTokenIs(ExpressionTokenType.QuestionMark))
{
while (operatorStack.Count != 0)
{
OperatorNode opNode = operatorStack.Pop();
opNode.right = expressionStack.Pop();
opNode.left = expressionStack.Pop();
expressionStack.Push(opNode);
}
OperatorNode condition = ASTNode.OperatorNode(OperatorType.TernaryCondition);
OperatorNode selection = ASTNode.OperatorNode(OperatorType.TernarySelection);
condition.WithLocation(tokenStream.Previous);
tokenStream.Advance();
int idx = tokenStream.FindMatchingTernaryColon();
if (idx != -1)
{
TokenStream stream = tokenStream.AdvanceAndReturnSubStream(idx);
// parse the left side of the : operator
ExpressionParser parser = new ExpressionParser(stream);
ASTNode leftNode = parser.ParseLoop();
parser.Release();
tokenStream.Advance(); // step over colon
ExpressionParser parserRight = new ExpressionParser(tokenStream);
ASTNode rightNode = parserRight.ParseLoop();
tokenStream.Set(parserRight.tokenStream.CurrentIndex);
parserRight.Release(false);
selection.left = leftNode;
selection.right = rightNode;
condition.left = expressionStack.Pop();
condition.right = selection;
expressionStack.Push(condition);
}
else
{
// read to end use implicit default value for left hand side
ExpressionParser parserLeft = new ExpressionParser(tokenStream);
ASTNode leftNode = parserLeft.ParseLoop();
tokenStream.Set(parserLeft.tokenStream.CurrentIndex);
parserLeft.Release(false);
selection.left = leftNode;
selection.right = ASTNode.DefaultLiteralNode("default");
condition.left = expressionStack.Pop();
condition.right = selection;
expressionStack.Push(condition);
}
continue;
}
OperatorNode op;
if (!ParseOperatorExpression(out op))
{
Abort();
break;
}
while (operatorStack.Count != 0 && op.priority <= operatorStack.Peek().priority)
{
OperatorNode opNode = operatorStack.Pop();
opNode.right = expressionStack.Pop();
opNode.left = expressionStack.Pop();
expressionStack.Push(opNode);
}
operatorStack.Push(op);
}
while (operatorStack.Count != 0)
{
OperatorNode opNode = operatorStack.Pop();
opNode.right = expressionStack.Pop();
opNode.left = expressionStack.Pop();
expressionStack.Push(opNode);
}
if (expressionStack.Count != 1)
{
Abort();
}
return(expressionStack.Pop());
}
private bool ParseDeclaration(ref ASTNode node)
{
AttributeNode attrNode = null;
LightList <AttributeNode> attributes = LightList <AttributeNode> .Get();
while (ParseAttribute(ref attrNode))
{
attributes.Add(attrNode);
if (tokenStream.Current != ExpressionTokenType.ArrayAccessOpen)
{
break;
}
}
if (attributes.size == 0)
{
LightList <AttributeNode> .Release(ref attributes);
}
if (tokenStream.Current != ExpressionTokenType.Identifier)
{
return(false);
}
// modifiers? -> returnType -> name -> signature -> openBrace * closeBrace
tokenStream.Save();
bool isStatic = false;
if (tokenStream.Current == "static")
{
isStatic = true;
tokenStream.Advance();
}
ExpressionParser parser = new ExpressionParser(tokenStream);
StructList <LambdaArgument> signature = null;
TypeLookup typeLookup = default;
if (!parser.ParseTypePath(ref typeLookup))
{
goto fail;
}
tokenStream.Set(parser.GetTokenPosition());
parser.Release(false);
if (tokenStream.Current != ExpressionTokenType.Identifier)
{
goto fail;
}
string name = tokenStream.Current.value;
tokenStream.Advance();
// if semi colon then we have a field!
if (tokenStream.Current == ExpressionTokenType.SemiColon)
{
tokenStream.Advance();
node = new FieldNode()
{
name = name,
isStatic = isStatic,
attributes = attributes,
typeLookup = typeLookup
};
return(true);
}
if (tokenStream.Current != ExpressionTokenType.ParenOpen)
{
goto fail;
}
signature = StructList <LambdaArgument> .Get();
if (tokenStream.NextTokenIs(ExpressionTokenType.ParenClose))
{
tokenStream.Advance(2);
}
else
{
int matchingIndex = tokenStream.FindMatchingIndex(ExpressionTokenType.ParenOpen, ExpressionTokenType.ParenClose);
if (matchingIndex == -1)
{
goto fail;
}
TokenStream subStream = tokenStream.AdvanceAndReturnSubStream(matchingIndex);
subStream.Advance();
tokenStream.Advance();
if (!ExpressionParser.ParseSignature(subStream, signature))
{
goto fail;
}
for (int i = 0; i < signature.size; i++)
{
if (signature.array[i].type == null)
{
throw new ParseException($"When defining a method you must specify a type for all arguments. Found identifier {signature.array[i].identifier} but no type was given.");
}
}
}
if (tokenStream.Current != ExpressionTokenType.ExpressionOpen)
{
goto fail;
}
BlockNode block = ParseBlock();
node = new MethodNode()
{
body = block,
returnTypeLookup = typeLookup,
attributes = attributes,
name = name,
isStatic = isStatic,
signatureList = signature != null?signature.ToArray() : s_EmptySignature
};
StructList <LambdaArgument> .Release(ref signature);
parser.Release(false);
return(true);
fail:
{
tokenStream.Restore();
parser.Release(false);
typeLookup.Release();
signature?.Release();
return(false);
}
}
private bool ParseLocalVariableDeclaration(ref ASTNode node)
{
ExpressionParser parser = default;
TypeLookup typeLookup = default;
if (tokenStream.Current == ExpressionTokenType.Var)
{
if (!tokenStream.NextTokenIs(ExpressionTokenType.Identifier))
{
return(false);
}
tokenStream.Advance();
}
else if (tokenStream.Current == ExpressionTokenType.Identifier)
{
tokenStream.Save();
parser = new ExpressionParser(tokenStream);
if (!parser.ParseTypePath(ref typeLookup))
{
goto fail;
}
tokenStream.Set(parser.GetTokenPosition());
parser.Release(false);
}
else
{
goto fail;
}
if (tokenStream.Current != ExpressionTokenType.Identifier)
{
goto fail;
}
string name = tokenStream.Current.value;
tokenStream.Advance();
if (tokenStream.Current == ExpressionTokenType.SemiColon)
{
tokenStream.Advance();
node = new LocalVariableNode()
{
name = name,
typeLookup = typeLookup // will be default for var
};
return(true);
}
if (tokenStream.Current == ExpressionTokenType.Assign)
{
// todo -- would fail on this: var x = new F(() => { return x; });
tokenStream.Advance();
ASTNode expression = null;
if (!ParseTerminatedExpression(ref expression))
{
goto fail;
}
node = new LocalVariableNode()
{
name = name,
value = expression,
typeLookup = typeLookup // will be default for var
};
return(true);
}
fail:
{
parser.Release(false);
typeLookup.Release();
tokenStream.Restore();
return(false);
}
}
