public BinaryExpression(int line, int column, Expression lhs, TokenType op, Expression rhs)
: base(line, column)
{
this.lhs = lhs;
this.op = op;
this.rhs = rhs;
}
private bool EvalCondition(Expression expr, TemplateContext context)
{
object val = expr.Eval(context);
if (val is Boolean)
return (Boolean)val;
else if (val is Int32)
return ((Int32)val) != 0;
else if (val is Decimal)
return ((Decimal)val) != 0;
else if (val != null)
return true;
else
return false;
}
private Expression ParseAdditiveExpressionRest(Expression lhs)
{
if (Current.TokenType == TokenType.Plus
|| Current.TokenType == TokenType.Minus)
{
Token tok = Consume(); // +, -
Expression rhs = ParseMultiplyExpression();
BinaryExpression lhsChild = new BinaryExpression(lhs.Line, lhs.Column, lhs, tok.TokenType, rhs);
return ParseAdditiveExpressionRest(lhsChild);
}
else
{
return lhs;
}
}
private Expression ParseMultiplyExpressionRest(Expression lhs)
{
if (Current.TokenType == TokenType.Mult
|| Current.TokenType == TokenType.Div
|| Current.TokenType == TokenType.Mod)
{
Token tok = Consume(); // *, /, %
Expression rhs = ParseUnaryExpression();
BinaryExpression lhsChild = new BinaryExpression(lhs.Line, lhs.Column, lhs, tok.TokenType, rhs);
return ParseMultiplyExpressionRest(lhsChild);
}
return lhs;
}
private Expression ParseLogicalExpressionRest(Expression lhs)
{
if (Current.TokenType == TokenType.And || Current.TokenType == TokenType.Or)
{
Consume(); // &&, ||
Expression rhs = ParseRelationalExpression();
BinaryExpression lhsChild = new BinaryExpression(lhs.Line, lhs.Column, lhs, TokenType.And, rhs);
return ParseLogicalExpressionRest(lhsChild);
}
else
{
return lhs;
}
}
