public static Expression CreateOld(MatchIterator iterator)
{
Token opToken;
if (iterator.NextIsToken(TokenType.Operator, out opToken))
{
// assume a left operator for now
Expression righExpr = Create(iterator);
return(new OperatorCall(opToken, null, righExpr));
}
Expression nextExpr;
if (iterator.NextIsKeySymbol(Symbols.OpenBracket))
{
iterator.AssertExpression(out nextExpr);
iterator.AssertKeySymbol(Symbols.CloseBracket, out _);
}
else
{
iterator.AssertExpression(out nextExpr);
}
if (iterator.AtEnd())
{
return(nextExpr);
}
if (iterator.Next(out List <CollectedIndex> indices))
{
foreach (CollectedIndex index in indices)
{
nextExpr = new Indexer(nextExpr, index.Open, index.Index, index.Close);
}
iterator.MoveNext();
}
if (iterator.AtEnd())
{
return(nextExpr);
}
iterator.AssertTokenType(TokenType.Operator, out opToken);
if (iterator.AtEnd())
{
// Assume a right operator for now
return(new OperatorCall(opToken, nextExpr, null));
}
// Assume a binary operator for now
Expression remainder = Create(iterator);
return(new OperatorCall(opToken, nextExpr, remainder));
}
public static LoopHeader Loop(MatchIterator iterator)
{
Expression array;
iterator.AssertKeyword(Keywords.Loop);
Token loop = (Token)iterator.Current;
if (iterator.AtEnd())
{
LoopHeader result = new LoopHeader(loop);
return(result);
}
iterator.AssertExpression(out Expression firstExpression);
if (iterator.AtEnd())
{
// Actually checking that this expression is an array is for
// a later step, when the messenger is available.
array = firstExpression;
LoopHeader result = new LoopHeader(loop, array);
return(result);
}
if (iterator.NextIsKeyword(Keywords.In, out Token inToken))
{
// Again, actually checking that this is indeed just a name
// has to wait for a later stage.
Expression name = firstExpression;
iterator.AssertExpression(out array);
iterator.AssertEnd();
LoopHeader result = new LoopHeader(loop, name, inToken, array);
return(result);
}
if (iterator.NextIsKeyword(Keywords.From, out Token from))
{
Expression name = firstExpression;
iterator.AssertExpression(out Expression start);
iterator.AssertKeyword(Keywords.To, out Token to);
iterator.AssertExpression(out Expression end);
iterator.AssertEnd();
LoopHeader result = new LoopHeader(
loop, name, from, start, to, end);
return(result);
}
throw iterator.UnexpectedEnd();
}
public static List <Expression> Arguments(MatchIterator iterator)
{
List <Expression> arguments = new List <Expression>();
if (iterator.AtEnd())
{
return(arguments);
}
do
{
iterator.AssertExpression(out Expression argument);
arguments.Add(argument);
}while (iterator.NextIsKeySymbol(Symbols.Comma));
iterator.AssertEnd();
return(arguments);
}
public static CollectedParameters Parameters(MatchIterator iterator)
{
List <SprakType> parameterTypes = new List <SprakType>();
List <string> parameterNames = new List <string>();
CollectedParameters result
= new CollectedParameters(parameterTypes, parameterNames);
if (iterator.AtEnd())
{
return(result);
}
do
{
iterator.AssertType(out SprakType type);
iterator.AssertName(out string name);
parameterTypes.Add(type);
parameterNames.Add(name);
}while (iterator.NextIsKeySymbol(Symbols.Comma));
iterator.AssertEnd();
return(result);
}
public static Expression Create(MatchIterator iterator)
{
LinkedList <object> items = new LinkedList <object>();
iterator.AssertNext();
// postfix unary operators are not supported here
// (Like i--, etc)
// I don't think they are really needed for sprak, and defaulting
// to assuming prefix simplifies things.
while (true)
{
items.AddLast(GetValue(iterator));
if (iterator.AtEnd())
{
break;
}
iterator.AssertTokenType(TokenType.Operator, out Token op);
items.AddLast(op);
if (iterator.AtEnd())
{
break;
}
}
void ParseOperatorToken(LinkedListNode <object> opNode)
{
Token token = (Token)opNode.Value;
LinkedListNode <object> leftNode = opNode.Previous;
LinkedListNode <object> rightNode = opNode.Next;
Expression left = (Expression)leftNode.Value;
Expression right = (Expression)rightNode?.Value;
OperatorCall result = new OperatorCall(token, left, right);
items.AddBefore(leftNode, result);
items.Remove(leftNode);
items.Remove(opNode);
if (rightNode != null)
{
items.Remove(rightNode);
}
}
LinkedListNode <object> current, next;
foreach (Operator[] group in Operator.OperatorPrecedenceGroups)
{
current = items.First.Next;
while (current != null)
{
next = current.Next?.Next;
Token token = (Token)current.Value;
if (Operator.TryParse(out Operator op, text:token.Content))
{
if (group.Contains(op))
{
ParseOperatorToken(current);
}
}
current = next;
}
}
current = items.First.Next;
while (current != null)
{
ParseOperatorToken(current);
current = current.Next?.Next;
}
if (items.First.Next != null)
{
throw new Exception("Unable to parse all operators");
}
return((Expression)items.First.Value);
}