/// <summary>
/// Parses an in edge expression with an enclosed variable definition.
/// Throws on mis match.
/// </summary>
/// <returns> An edge node.</returns>
private static Node ParseInEdge(ref int position, List <Token> tokens)
{
EdgeNode edgeNode;
MatchVariableNode matchVariableNode;
// -
if (!CheckToken(position, Token.TokenType.Dash, tokens))
{
throw new ArgumentException($"EdgeParser, expected beginning of edge.");
}
else
{
position++;
}
CheckLeftBrace(ref position, tokens);
matchVariableNode = (MatchVariableNode)(ParseMatchVariable(ref position, tokens));
CheckRightBrace(ref position, tokens);
// -
if (CheckToken(position, Token.TokenType.Dash, tokens))
{
position++;
edgeNode = new InEdgeNode();
}
else
{
throw new ArgumentException($"MatchParser, expected ending of edge.");
}
edgeNode.AddMatchVariable(matchVariableNode);
return(edgeNode);
}
/// <summary>
/// Tries to parse an anonymous edge type.
/// </summary>
/// <returns> An anonymous edge or null. </returns>
static private Node TryParseEmptyEdge(ref int position, List <Token> tokens)
{
EdgeNode edgeNode;
if (CheckEmptyAnyEdge(ref position, tokens))
{
edgeNode = new AnyEdgeNode();
position++;
return(edgeNode);
}
else if (CheckEmptyOutEdge(ref position, tokens))
{
edgeNode = new OutEdgeNode();
position = position + 2;
return(edgeNode);
}
else if (CheckEmptyInEdge(ref position, tokens))
{
edgeNode = new InEdgeNode();
position = position + 2;
return(edgeNode);
}
else
{
return(null);
}
}
/// <summary>
/// Tries to jump to a variable node inside an edge or to the next vertex.
/// </summary>
public void Visit(InEdgeNode node)
{
this.readingVertex = false;
ParsedPatternNode em = new InEdgeParsedPatternNode();
currentPattern.AddParsedPatternNode(em);
if (node.matchVariable != null)
{
node.matchVariable.Accept(this);
}
if (node.next == null)
{
throw new ArgumentException($"{this.GetType()}, missing end vertex from edge.");
}
else
{
node.next.Accept(this);
}
}
public void Visit(InEdgeNode node)
{
throw new NotImplementedException();
}