public static FunctionHeader Header(MatchIterator iterator)
{
iterator.AssertTokenType(TokenType.Type, out Token typeToken);
iterator.AssertTokenType(TokenType.Name, out Token nameToken);
iterator.AssertKeySymbol(Symbols.OpenBracket, out _);
Token open = (Token)iterator.Current;
CollectedParameters parameters;
if (iterator.Next(out parameters))
{
iterator.MoveNext();
}
else
{
parameters = new CollectedParameters();
}
iterator.AssertKeySymbol(Symbols.CloseBracket, out _);
Token end = (Token)iterator.Current;
iterator.AssertEnd();
FunctionTypeSignature typeSignature = new FunctionTypeSignature(parameters.Types);
FunctionSignature signature = new FunctionSignature(
FunctionSignature.Local, nameToken.Content, typeSignature);
FunctionHeader result = new FunctionHeader(
typeToken, nameToken, open, end, signature, parameters.Names);
return(result);
}
public static VariableAssignment Assignment(MatchIterator iterator)
{
if (!iterator.NextIsToken(TokenType.Type, out Token type))
{
type = null;
}
iterator.AssertTokenType(TokenType.Name, out Token name);
if (iterator.Next(out List <CollectedIndex> indices))
{
iterator.MoveNext();
}
else
{
indices = new List <CollectedIndex>(0);
}
iterator.AssertTokenType(TokenType.Operator, out Token op);
if (!iterator.NextIsExpression(out Expression value))
{
value = null;
}
iterator.AssertEnd();
return(new VariableAssignment(type, name, indices, op, value));
}
public static FunctionCall Call(MatchIterator iterator)
{
// It would be cool in patterner v2 if the pattern was constructed in the same method as the finalizer.
// For example, a "dummy" matchIterator could be passed through here and pick up the requirements, perhaps?
// This would, of course, require the big feature of pattern simplification
// It would also require defining a special "Expression" subpattern? At this point it would be better if everything were an expression, I guess
iterator.AssertTokenType(TokenType.Name, out Token name);
iterator.AssertKeySymbol(Symbols.OpenBracket, out _);
Token open = (Token)iterator.Current;
if (iterator.Next(out List <Expression> arguments))
{
iterator.MoveNext();
}
else
{
arguments = new List <Expression>();
}
iterator.AssertKeySymbol(Symbols.CloseBracket, out _);
Token end = (Token)iterator.Current;
iterator.AssertEnd();
FunctionCall result = new FunctionCall(name, open, end, arguments);
return(result);
}
public static VariableReference CreateReference(MatchIterator iterator)
{
iterator.AssertTokenType(TokenType.Name, out Token token);
iterator.AssertEnd();
return(new VariableReference(token));
}
public static Command Create(MatchIterator iterator)
{
iterator.AssertTokenType(TokenType.KeyWord, out Token keyWord);
iterator.AssertEnd();
Command result = new Command(keyWord);
return(result);
}
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 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);
}