private IEnumerable <string> GetSubAliasNames(RegexAlias alias)
{
return(Regex.Matches(alias.RegexPattern, AliasPattern)
.Cast <Match>()
.Select(x => x.Value.Substring(2, x.Value.Length - 3))
.Distinct());
}
private void ComputeRawRegex(RegexAlias alias, List <RegexAlias> computedAliases)
{
// Add this as a computed dependency to detect circular dependencies
computedAliases.Add(alias);
foreach (var subAliasName in GetSubAliasNames(alias))
{
var matchName = string.Concat("%{", subAliasName, "}");
// Find an alias with the specified name and put its
// regex pattern into the current alias' pattern
var subAlias = _aliases.FirstOrDefault(x => x.Name.Equals(subAliasName, StringComparison.InvariantCultureIgnoreCase));
if (subAlias != null)
{
// If the subAlias has already been computed this run,
// we have a circular dependency
if (computedAliases.Contains(subAlias))
{
throw new InvalidOperationException("Circular dependency detected while computing alias dependencies");
}
// Compute the sub alias' regex
ComputeRawRegex(subAlias, computedAliases.ToList());
alias.RegexPattern = alias.RegexPattern.Replace(matchName, subAlias.RegexPattern);
}
}
}