Add pdb support.

README.md

@@ -27,7 +27,7 @@ a = 1
 will generate
 
 ```
-<module> (my_script.py:5):
+> <module> (my_script.py:5):
 a:
 0
 ->
@@ -41,22 +41,8 @@ from watchpoints import watch
 
 a = []
 watch(a)
-a.append(1)
-a = {}
-```
-
-```
-<module> (my_script.py:5):
-a:
-[]
-->
-[1]
-
-<module> (my_script.py:6):
-a:
-[1]
-->
-{}
+a.append(1)  # Trigger
+a = {}  # Trigger
 ```
 
 Even better, it can track the changes of the object after the changes of the variable
@@ -66,22 +52,8 @@ from watchpoints import watch
 
 a = []
 watch(a)
-a = {}
-a["a"] = 2
-```
-
-```
-<module> (my_script.py:5):
-a:
-[]
-->
-{}
-
-<module> (my_script).py:6):
-a:
-{}
-->
-{'a': 2}
+a = {}  # Trigger
+a["a"] = 2  # Trigger
 ```
 
 Without doubts, it works whenever the object is changed, even if it's not in the same scope
@@ -98,7 +70,7 @@ func(a)
 ```
 
 ```
-func (my_script.py:4):
+> func (my_script.py:4):
 a:
 {}
 ->
@@ -117,22 +89,8 @@ class MyObj:
 obj = MyObj()
 d = {"a": 0}
 watch(obj.a, d["a"])  # Yes you can do this
-obj.a = 1
-d["a"] = 1
-```
-
-```
-<module> (my_script.py:10):
-obj.a:
-0
-->
-1
-
-<module> (my_script.py:11):
-d["a"]:
-0
-->
-1
+obj.a = 1  # Trigger
+d["a"] = 1  # Trigger
 ```
 
 **watchpoints will try to guess what you want to monitor, and monitor it as you expect**(well most of the time)
@@ -199,6 +157,17 @@ Use ```restore()``` to restore the default callback
 watch.restore()
 ```
 
+### Integrating with pdb
+
+watchpoints can be used with pdb with ease. You can trigger pdb just like using ```breakpoint()``` when
+your monitored variable is changed. Simply do
+
+```python
+watch.config(pdb=True)
+```
+
+When you are in pdb, use ```q(uit)``` command to exit pdb, and the next change on the variable will trigger the pdb again.
+
 ## Bugs/Requests
 
 Please send bug reports and feature requests through [github issue tracker](https://github.com/gaogaotiantian/watchpoints/issues).

src/watchpoints/watch.py

@@ -2,7 +2,9 @@
 # For details: https://github.com/gaogaotiantian/watchpoints/blob/master/NOTICE.txt
 
 
+from bdb import BdbQuit
 import inspect
+import pdb
 import sys
 from .util import getargnodes
 from .watch_element import WatchElement
@@ -15,6 +17,8 @@ def __init__(self):
         self.tracefunc_stack = []
         self.enable = False
         self._callback = self._default_callback
+        self.pdb = None
+        self.pdb_enable = False
 
     def __call__(self, *args, **kwargs):
         frame = inspect.currentframe().f_back
@@ -40,18 +44,25 @@ def start_trace(self, frame):
         if not self.enable:
             self.enable = True
             self.tracefunc_stack.append(sys.gettrace())
-            sys.settrace(self.tracefunc)
-            frame.f_trace = self.tracefunc
             self._prev_funcname = frame.f_code.co_name
             self._prev_filename = frame.f_code.co_filename
             self._prev_lineno = frame.f_lineno
+            while frame:
+                frame.f_trace = self.tracefunc
+                frame = frame.f_back
+
+            sys.settrace(self.tracefunc)
 
     def stop_trace(self, frame):
         if self.enable:
+            self.enable = False
             tf = self.tracefunc_stack.pop()
-            sys.settrace(tf)
             frame.f_trace = tf
-            self.enable = False
+            while frame:
+                frame.f_trace = tf
+                frame = frame.f_back
+
+            sys.settrace(tf)
 
     def unwatch(self, *args):
         frame = inspect.currentframe().f_back
@@ -69,6 +80,10 @@ def config(self, **kwargs):
         if "callback" in kwargs:
             self._callback = kwargs["callback"]
 
+        if "pdb" in kwargs:
+            self.pdb = pdb.Pdb()
+            self.pdb.reset()
+
     def restore(self):
         self._callback = self._default_callback
 
@@ -77,6 +92,8 @@ def tracefunc(self, frame, event, arg):
         for elem in self.watch_list:
             changed, exist = elem.changed(frame)
             if changed:
+                if self.pdb:
+                    self.pdb_enable = True
                 if elem._callback:
                     elem._callback(frame, elem, (self._prev_funcname, self._prev_filename, self._prev_lineno))
                 else:
@@ -92,6 +109,15 @@ def tracefunc(self, frame, event, arg):
         self._prev_filename = frame.f_code.co_filename
         self._prev_lineno = frame.f_lineno
 
+        if self.pdb_enable:
+            try:
+                self.pdb.trace_dispatch(frame, event, arg)
+            except BdbQuit:
+                self.pdb_enable = False
+                self.pdb.reset()
+                self.stop_trace(frame)
+                self.start_trace(frame)
+
         return self.tracefunc
 
     def _default_callback(self, frame, elem, exec_info):

src/watchpoints/watch_print.py

@@ -26,7 +26,7 @@ def __call__(self, frame, elem, exec_info):
         p("")
 
     def _file_string(self, exec_info):
-        return f"{exec_info[0]} ({exec_info[1]}:{exec_info[2]}):"
+        return f"> {exec_info[0]} ({exec_info[1]}:{exec_info[2]}):"
 
     def printer(self, obj):
         if type(obj) is str: