public static StringSegment ParseConditionExpression(this StringSegment literal, out ConditionExpression expr)
{
BooleanExpression rootExpr = null;
BinaryExpression lhsBinaryExpr = null, rhsBinaryExpr = null;
literal = literal.AdvancePastWhitespace();
while (!literal.IsNullOrEmpty())
{
literal = literal.ParseBinaryExpression(out lhsBinaryExpr);
literal = literal.AdvancePastWhitespace();
if (literal.IsNullOrEmpty() && rootExpr == null)
{
expr = lhsBinaryExpr;
return(literal);
}
literal = literal.ParseNextToken(out object value, out JsBinding andOrToken);
if (andOrToken == null || !andOrToken.Binding.Equals(BooleanExpression.OrKeyword) && !andOrToken.Binding.Equals(BooleanExpression.AndKeyword))
{
throw new NotSupportedException($"Invalid sytnax: Expected 'and', 'or' keywords but found instead '{value ?? andOrToken}', near '{literal.SubstringWithElipsis(0,50)}'");
}
var isOr = andOrToken.Binding.Equals(BooleanExpression.OrKeyword);
literal = literal.ParseBinaryExpression(out rhsBinaryExpr);
if (rootExpr == null)
{
rootExpr = isOr
? (BooleanExpression) new OrExpression(lhsBinaryExpr)
: new AndExpression(lhsBinaryExpr);
}
if (rootExpr.MatchesBinding(andOrToken))
{
rootExpr.Expressions.Add(rhsBinaryExpr);
}
else
{
rootExpr = isOr
? (BooleanExpression) new OrExpression(rootExpr, rhsBinaryExpr)
: new AndExpression(rootExpr, rhsBinaryExpr);
}
}
expr = rootExpr;
return(literal);
}
public static StringSegment ParseConditionExpression(this string literal, out ConditionExpression expr) => literal.ToStringSegment().ParseConditionExpression(out expr);