/// <summary>
/// parse text using entity extractors into a list of tokens lists
/// </summary>
/// <param name="properties"></param>
/// <param name="customerMessage"></param>
/// <param name="serviceProvider"></param>
/// <returns></returns>
public static List <List <Token> > ParseText(Dictionary <string, object> properties, string customerMessage, IServiceProvider serviceProvider)
{
using (var scope = serviceProvider.CreateScope())
{
var tokenisers = scope.ServiceProvider.GetServices <IEntityTokeniser>();
TokenTree tree = new TokenTree()
.Build(tokenisers, customerMessage, properties);
var flattenedTokens = tree.Flatten();
return(flattenedTokens);
}
}
internal static List <List <Token> > Flatten(this TokenTree tree)
{
List <List <TokenNode> > master = new List <List <TokenNode> >();
List <TokenNode> list = new List <TokenNode>();
tree.Head.Flatten(master, list);
List <List <Token> > final = new List <List <Token> >();
foreach (var tnl in master)
{
final.Add(tnl.Select(x => x.Token).ToList());
}
return(final);
}
static internal TokenTree Build(this TokenTree tree, IEnumerable <IEntityTokeniser> tokenisers, string text, Dictionary <string, object> properties)
{
foreach (var tokeniser in tokenisers)
{
tokeniser.BeginParse(text, properties);
}
TokenNode current = new TokenNode
{
Token = new StartToken {
Pos = 0, Length = 0
}
};
tree.Head = current;
int currentOffset = 0;
ParseText(tokenisers, tree, currentOffset, current, text, properties);
return(tree);
}
internal static TokenTree PrintTree(this TokenTree tree)
{
tree.Head.PrintTree(0);
return(tree);
}
/// <summary>
/// tokenise the text into a token tree. This method is recursive.
/// </summary>
/// <param name="text"></param>
/// <param name="recognisers"></param>
/// <returns></returns>
static private void ParseText(IEnumerable <IEntityTokeniser> tokenisers, TokenTree tree, int currentOffset, TokenNode current, string text, Dictionary <string, object> Properties)
{
var tokens = GetFirstTokenList(tokenisers, text.Substring(currentOffset), Properties);
// end of parse.. add trailing text if any
if (tokens == null || tokens.Count == 0)
{
var subtext = text.Substring(currentOffset).Trim();
if (subtext.Length > 0)
{
TextToken textToken = new TextToken
{
Text = subtext,
Pos = currentOffset,
Length = subtext.Length
};
TokenNode node = new TokenNode {
Token = textToken
};
current.Children.Add(node);
}
return;
}
// calc start pos of the tokens (all will have same start pos)
var tokenpos = currentOffset + tokens[0].Pos;
// *** create infill ***
// tokens are offset from start of text so create infilling text token
if (tokenpos > currentOffset)
{
var infill_txt = text.Substring(currentOffset, tokenpos - currentOffset);
// only add infill if it contains more than just white space
if (infill_txt.Trim().Length > 0)
{
TextToken textToken = new TextToken
{
Text = infill_txt,
Pos = currentOffset,
Length = tokenpos - currentOffset - 1
};
TokenNode infill_node = new TokenNode {
Token = textToken
};
current.Children.Add(infill_node);
current = infill_node;
}
}
// we have tokens to deal with
// for each child, find more tokens
foreach (var token in tokens)
{
var thiscurrent = current;
// update the current offset to work from
var nextoffset = currentOffset + (token.Pos + token.Length);
TokenNode node = new TokenNode {
Token = token
};
thiscurrent.Children.Add(node);
ParseText(tokenisers, tree, nextoffset, node, text, Properties);
}
}
