void EvalSubstitution(SubstitutionExpression expr, EvalOption option)
{
option = new EvalOption();
option.ForWriting = true;
var target = Eval(expr.Target, option);
var value = Eval(expr.Value, null);
if (value is Attribute)
{
value = (value as Attribute).Value;
}
var targetAttribute = target as Attribute;
if (targetAttribute == null)
{
throw new InvalidSubstitution(expr.Line);
}
if (value is Value)
{
targetAttribute.Value = value;
}
}
Expression[] Sentence()
{
List <Expression> sentences = new List <Expression>();
while (true)
{
var empty = Peek();
if (empty == null)
{
break;
}
if (empty.Type == TokenType.NewLine)
{
Next();
continue;
}
var lhs = Expr();
var token = Peek();
if (token != null)
{
if (token.Type == TokenType.Equal)
{
Next();
var rhs = Expr();
var substitution = new SubstitutionExpression();
substitution.Target = lhs;
substitution.Value = rhs;
substitution.Line = token.Line;
sentences.Add(substitution);
}
else
{
sentences.Add(lhs);
}
}
else
{
sentences.Add(lhs);
break;
}
}
return(sentences.ToArray());
}