public static string ExpandString(this KeywordExpander keywordExpander, IEnumerable <char> input)
{
var sb = new StringBuilder();
foreach (var c in keywordExpander.Expand(input))
{
sb.Append(c);
}
return(sb.ToString());
}
public static void Expand(this KeywordExpander keywordExpander, TextReader input, TextWriter output)
{
var _input = Read(input);
var _output = keywordExpander.Expand(_input);
foreach (var c in _output)
{
output.Write(c);
}
}
public override IEnumerable <char> ExpandKeyword(string keyword)
{
KeywordExpander expander = null;
var seperator = keyword.IndexOf('.');
string prefix = null;
if (seperator != -1)
{
prefix = keyword.Substring(0, seperator);
keyword = keyword.Substring(seperator + 1);
}
// First, see if we have a hard override for a particular keyword to come from
// a particular expander
if (keywordToExpanderMapping != null)
{
keywordToExpanderMapping.TryGetValue(keyword, out expander);
}
// Then, see if we have a prefix to specify a particular expander i.e. [prefix].[keyword]
if (prefix != null)
{
expander = expanders[prefix];
}
// Finally, if no expander has been found, then iterate through each in order of Add-ition
// looking for the specified keyword
if (expander == null)
{
foreach (var e in expanders.Values)
{
if (e.CanExpandKeyword(keyword))
{
return(e.ExpandKeyword(keyword));
}
}
}
else
{
// Alternatively, if we did find an appropriate expander candidate, then
// expand using it here
return(expander.ExpandKeyword(keyword));
}
throw new KeyNotFoundException("Cannot expand keyword: " + keyword);
}
/// <summary>
/// Add a sub-keyword expander to this aggregate keyword expander, qualified by a keyword prefix
/// </summary>
/// <param name="e">Expander to additionally add to this aggregator</param>
/// <param name="prefix">prefix to qualify this particular expander by</param>
public void Add(KeywordExpander e, string prefix)
{
expanders.Add(prefix, e);
}
