New: a new interpretor based on Andrew Ng theory. (#3532)

### What problem does this PR solve?

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

agent/canvas.py

@@ -199,7 +199,7 @@ class Canvas(ABC):
                         if any([cc not in self.path[-1] for cc in cpids]):
                             if c not in waiting: waiting.append(c)
                             continue
-                    yield "'{}' is running...".format(self.get_compnent_name(c))
+                    yield "*'{}'* is running...🕞".format(self.get_compnent_name(c))
                     ans = cpn.run(self.history, **kwargs)
                     self.path[-1].append(c)
             ran += 1
@@ -224,28 +224,16 @@ class Canvas(ABC):
                     for m in prepare2run([switch_out]):
                         yield {"content": m, "running_status": True}
                 except Exception as e:
-                    for p in [c for p in self.path for c in p][::-1]:
-                        if p.lower().find("answer") >= 0:
-                            self.get_component(p)["obj"].set_exception(e)
-                            for m in prepare2run([p]):
-                                yield {"content": m, "running_status": True}
-                            break
+                    yield {"content": "*Exception*: {}".format(e), "running_status": True}
                     logging.exception("Canvas.run got exception")
-                    break
                 continue
 
             try:
                 for m in prepare2run(cpn["downstream"]):
                     yield {"content": m, "running_status": True}
             except Exception as e:
-                for p in [c for p in self.path for c in p][::-1]:
-                    if p.lower().find("answer") >= 0:
-                        self.get_component(p)["obj"].set_exception(e)
-                        for m in prepare2run([p]):
-                            yield {"content": m, "running_status": True}
-                        break
+                yield {"content": "*Exception*: {}".format(e), "running_status": True}
                 logging.exception("Canvas.run got exception")
-                break
 
             if ran >= len(self.path[-1]) and waiting:
                 without_dependent_checking = waiting

agent/component/base.py

@@ -454,7 +454,7 @@ class ComponentBase(ABC):
             outs = []
             for q in self._param.query:
                 if q["component_id"]:
-                    if q["component_id"].split("@")[0].lower().find("begin") > 0:
+                    if q["component_id"].split("@")[0].lower().find("begin") >= 0:
                         cpn_id, key = q["component_id"].split("@")
                         for p in self._canvas.get_component(cpn_id)["obj"]._param.query:
                             if p["key"] == key:

agent/component/generate.py

@@ -124,11 +124,16 @@ class Generate(ComponentBase):
 
             cpn = self._canvas.get_component(component_id)["obj"]
             if cpn.component_name.lower() == "answer":
-                kwargs[para["key"]] = self._canvas.get_history(1)[0]["content"]
+                hist = self._canvas.get_history(1)
+                if hist:
+                    hist = hist[0]["content"]
+                else:
+                    hist = ""
+                kwargs[para["key"]] = hist
                 continue
             _, out = cpn.output(allow_partial=False)
             if "content" not in out.columns:
-                kwargs[para["key"]] = "Nothing"
+                kwargs[para["key"]] = ""
             else:
                 if cpn.component_name.lower() == "retrieval":
                     retrieval_res.append(out)