public override void EvaluateNode(EvaluationContext context, AstMode mode)
{
// evaluate expression
Expression.Evaluate(context, AstMode.Read);
// extract last recognized pattern (it contains bound variables)
var lastPattern = context.GetLastPattern();
if (lastPattern == null)
{
context.ThrowError("Internal error: last recognized pattern is lost");
}
// with-clause
if (Block != null)
{
Block.BlockPattern = lastPattern;
Block.Evaluate(context, mode);
// with-clause is always successful
context.Data.Push(true);
}
// where-clause
if (Pattern != null)
{
EvaluateWhereClause(lastPattern, context, mode);
}
}
public override void EvaluateNode(EvaluationContext context, AstMode mode)
{
// read variable from last recognized pattern
if (mode == AstMode.Read)
{
if (context.GetLastPattern() == null)
{
context.ThrowError("No pattern recognized");
}
// push variable contents onto stack
var pattern = context.GetLastPattern();
context.Data.Push(pattern.GetVariable(Index));
return;
}
// create variable for pattern matching
context.Data.Push(CreateVariable());
}
