/// <summary>
///
/// </summary>
/// <param name="tokens"></param>
public VarNode(string[] tokens) : base(tokens)
{
var parser = new Parse.Var(tokens);
parser.ParseLhs();
parser.ParseRhs();
Lhs = parser.Lhs;
Rhs = parser.Rhs;
RhsType = parser.RhsType;
IsConstant = parser.IsConstant;
}
/// <summary>
///
/// </summary>
/// <param name="tokens"></param>
public IfNode(string[] tokens) : base(tokens)
{
var parser = new Parse.If(tokens);
Lhs = parser.Lhs;
Rhs = parser.Rhs;
IfType = parser.Type;
LhsType = parser.LhsType;
RhsType = parser.RhsType;
InverseEval = parser.InverseEval;
ComparisonOperator = parser.ComparisonOperator;
}
/// <summary>
///
/// </summary>
/// <param name="tokens"></param>
public UseNode(string[] tokens) : base(tokens)
{
var parser = new Parse.Use(tokens);
Arg = parser.Arg;
}
/// <summary>
///
/// </summary>
/// <param name="tokens"></param>
/// <exception cref="ArgumentException"></exception>
public If(IEnumerable <string> tokens) : base(tokens)
{
InverseEval = false;
Type = IfType.Unknown;
Consume();
switch (Peek())
{
case Tokens.TokenType.BooleanFalse:
case Tokens.TokenType.BooleanTrue:
{
var(_, s) = Consume();
Type = s == Tokens.TokenType.BooleanFalse ?
IfType.EvaluatedToFalse : IfType.EvaluatedToTrue;
Ensure(0);
return;
}
}
if (Peek() == Tokens.TokenType.NotOperator)
{
InverseEval = true;
Consume();
}
(Lhs, LhsType) = Consume();
var _ = LhsType switch
{
Tokens.TokenType.Variable => true,
Tokens.TokenType.Numeric => true,
Tokens.TokenType.StringLiteral => true,
_ => throw new ArgumentException("parse: invalid LHS for if")
};
if (Empty())
{
Type = IfType.VariableLookup;
return;
}
// ==, !=, <, <=, >, >=
// is, is not
// consume the first part of the operator
var(c, compType) = Consume();
var comp = (string)c;
if (compType == Tokens.TokenType.Is)
{
// is -> ==
comp = "==";
// is not -> !=
if (Peek() == Tokens.TokenType.Not)
{
comp = "!=";
Consume(); // not
}
}
else
{
// <=, >=
if (Peek() == Tokens.TokenType.EqualTo)
{
var(t, _) = Consume();
comp += (string)t;
}
}
ComparisonOperator = Tokens.GetTokenType(comp);
var isValid = ComparisonOperator switch
{
Tokens.TokenType.LessThan => true,
Tokens.TokenType.LessThanEq => true,
Tokens.TokenType.GreaterThan => true,
Tokens.TokenType.GreaterThanEq => true,
Tokens.TokenType.CompEq => true,
Tokens.TokenType.NotEqual => true,
_ => false
};
if (!isValid)
{
throw new ArgumentException($"fatal: invalid comparison operator {comp}");
}
(Rhs, RhsType) = Consume();
_ = RhsType switch
{
Tokens.TokenType.Variable => true,
Tokens.TokenType.Numeric => true,
Tokens.TokenType.StringLiteral => true,
_ => throw new ArgumentException("parse: invalid RHS for if")
};
Ensure(0);
if (Type == IfType.Unknown)
{
Type = IfType.SimpleComparison;
}
}
}
}
