public override Production Parse(List <Token> tokens)
{
var firstParen = tokens.First();
if (firstParen.TokenClass != TokenClass.StartScope)
{
return(new Production(null, tokens));
}
var current = new ScopeExpression().Parse(tokens);
var remaining = current.RemainingTokens.ToList();
while (remaining.Any() && remaining.FirstOrDefault() != null && remaining[0].TokenClass != TokenClass.EndScope)
{
Expression parsed;
switch (remaining.First().TokenClass)
{
case TokenClass.ReplacementSymbol:
current = new OperationExpression().Parse(remaining);
if (current.Expression != null)
{
break;
}
if (Constituents.Count > 0)
{
return(new Production(null, tokens)); //cannot have multiple value types in a row
}
current = new ReplacementSymbolExpression().Parse(remaining);
break;
case TokenClass.Integer:
case TokenClass.Float:
current = new OperationExpression().Parse(remaining);
if (current.Expression != null)
{
break;
}
if (Constituents.Count > 0)
{
return(new Production(null, tokens));
}
current = NumericExpression.TryParseNumeric(remaining);
break;
case TokenClass.String:
current = new OperationExpression().Parse(remaining);
if (current.Expression != null)
{
break;
}
if (Constituents.Count > 0)
{
return(new Production(null, tokens));
}
current = new StringExpression().Parse(remaining);
break;
case TokenClass.Boolean:
current = new OperationExpression().Parse(remaining);
if (current.Expression != null)
{
break;
}
if (Constituents.Count > 0)
{
return(new Production(null, tokens));
}
current = new BooleanExpression().Parse(remaining);
break;
case TokenClass.Symbol:
current = new FunctionExpression().Parse(remaining);
if (current.Expression != null)
{
break;
}
if (Constituents.Count > 0)
{
return(new Production(null, tokens));
}
current = new SymbolExpression().Parse(remaining);
break;
case TokenClass.StartScope:
current = new SeparatedExpression().Parse(remaining);
if (current.Expression != null)
{
break;
}
if (Constituents.Count > 0)
{
return(new Production(null, tokens));
}
current = new ScopedExpression().Parse(remaining);
break;
case TokenClass.Whitespace:
current = new WhitespaceExpression().Parse(remaining);
break;
case TokenClass.Operator:
if (Constituents.Count != 1)
{
return(new Production(null, remaining));
}
current = new OperationExpression().Parse(Constituents.First(), remaining);
if (current.Expression == null)
{
break;
}
Constituents.Clear();
break;
default:
return(new Production(null, remaining));
break;
}
if (current.Expression == null)
{
return(new Production(null, tokens));
}
if (!(current.Expression is WhitespaceExpression))
{
Constituents.Add(current.Expression);
}
remaining = current.RemainingTokens;
}
if (remaining.None())
{
return(new Production(null, tokens));
}
if (remaining[0].TokenClass != TokenClass.EndScope)
{
return(new Production(null, tokens));
}
return(new Production(this, remaining.Skip(1).ToList()));
}
