public CapturedState(TextBuffer before, TextBuffer after, BindingList <LogicVariable> bindings, State state) : this(TextBuffer.Difference(before, after), bindings, state) { }
/// <summary> /// Call this task with the specified arguments /// </summary> /// <param name="arglist">Task arguments</param> /// <param name="output">Output accumulated so far</param> /// <param name="env">Binding environment</param> /// <param name="predecessor">Most recently succeeded MethodCallFrame</param> /// <param name="k">Continuation</param> /// <returns>True if task succeeded and continuation succeeded</returns> /// <exception cref="CallFailedException">If the task fails</exception> public override bool Call(object[] arglist, TextBuffer output, BindingEnvironment env, MethodCallFrame predecessor, Step.Continuation k) { string lastToken = null; if (Suffix) { (lastToken, output) = output.Unappend(); arglist = new object[] { lastToken }; } ArgumentCountException.Check(this, this.ArgCount, arglist); var successCount = 0; if (ReadCache) { // Check for a hit in the cache. If we find one, we're done. if (Cache.TryGetValue(env.State, arglist, out var result)) { if (result.Success) { if (Function) { // We got a hit, and since this is a function, it's the only allowable hit. // So we succeed deterministically. return(env.Unify(arglist[arglist.Length - 1], result.FunctionValue, out BindingList <LogicVariable> u) && k(output.Append(result.Text), u, env.State, predecessor)); } else { successCount++; if (k(output.Append(result.Text), env.Unifications, env.State, predecessor)) { return(true); } } } else { // We have a match on a cached fail result, so force a failure, skipping over the methods. goto failed; } } else if (arglist.Any(x => x is LogicVariable)) { foreach (var pair in Cache.Bindings(env.State)) { if (pair.Value.Success && env.UnifyArrays((object[])pair.Key, arglist, out BindingList <LogicVariable> unifications)) { successCount++; if (k(output.Append(pair.Value.Text), unifications, env.State, predecessor)) { return(true); } } } } } if (ContainsCoolStep) { var s = env.State; s = CallCounts.SetItem(s, this, CallCount(s) + 1); env = new BindingEnvironment(env, env.Unifications, s); } var methods = this.EffectiveMethods; for (var index = 0; index < methods.Count && !(this.Deterministic && successCount > 0); index++) { var method = methods[index]; if (method.Try(arglist, output, env, predecessor, (o, u, s, newPredecessor) => { successCount++; if (WriteCache) { var final = env.ResolveList(arglist, u); if (Term.IsGround(final)) { s = StoreResult(s, final, new CachedResult(true, Function?final[final.Length - 1]:null, TextBuffer.Difference(output, o))); } } return(k(o, u, s, newPredecessor)); })) { return(true); } if (Suffix) { // Undo any overwriting that the method might have done output.Buffer[output.Length - 1] = lastToken; } } failed: var currentFrame = MethodCallFrame.CurrentFrame = env.Frame; if (currentFrame != null) { currentFrame.BindingsAtCallTime = env.Unifications; } if (successCount == 0 && this.MustSucceed) { throw new CallFailedException(this, arglist); } if (currentFrame != null) { env.Module.TraceMethod(Module.MethodTraceEvent.CallFail, currentFrame.Method, currentFrame.Arglist, output, env); MethodCallFrame.CurrentFrame = currentFrame.Predecessor; } // Failure return(false); }