Metadata-Version: 2.1
Name: watchpoints
Version: 0.1.0
Summary: watchpoints monitors read and write on variables
Home-page: https://github.com/gaogaotiantian/watchpoints
Author: Tian Gao
Author-email: gaogaotiantian@hotmail.com
License: UNKNOWN
Description: # watchpoints
        
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        watchpoints is an easy-to-use, intuitive variable/object monitor tool for python that behaves similar to watchpoints in gdb.
        
        ## Install
        
        ```
        pip install watchpoints
        ```
        
        ## Usage
        
        ### watch
        
        Simply ```watch``` the variables you need to monitor!
        
        ```python
        from watchpoints import watch
        
        a = 0
        watch(a)
        a = 1
        ```
        
        will generate
        
        ```
        > <module> (my_script.py:5):
        >     a = 1
        a:
        0
        ->
        1
        ```
        
        It works on both variable change and object change
        
        ```python
        from watchpoints import watch
        
        a = []
        watch(a)
        a.append(1)  # Trigger
        a = {}  # Trigger
        ```
        
        Even better, it can track the changes of the object after the changes of the variable
        
        ```python
        from watchpoints import watch
        
        a = []
        watch(a)
        a = {}  # Trigger
        a["a"] = 2  # Trigger
        ```
        
        Without doubts, it works whenever the object is changed, even if it's not in the same scope
        
        ```python
        from watchpoints import watch
        
        def func(var):
            var["a"] = 1
        
        a = {}
        watch(a)
        func(a)
        ```
        
        ```
        > func (my_script.py:4):
        >     var["a"] = 1
        a:
        {}
        ->
        {'a': 1}
        ```
        
        As you can imagine, you can monitor attributes of an object, or a specific element of a list or a dict
        
        ```python
        from watchpoints import watch
        
        class MyObj:
            def __init__(self):
                self.a = 0
        
        obj = MyObj()
        d = {"a": 0}
        watch(obj.a, d["a"])  # Yes you can do this
        obj.a = 1  # Trigger
        d["a"] = 1  # Trigger
        ```
        
        Also, watchpoints supports native ```threading``` library for multi-threading. It will tell you which thread is changing the
        value as well.
        
        ```
        > Thread-1
        > run (my_script.py:15):
        >     a[0] = i
        a:
        [0]
        ->
        [1]
        
        > Thread-2
        > run (my_script).py:15):
        >     a[0] = i
        a:
        [1]
        ->
        [2]
        ```
        
        **watchpoints will try to guess what you want to monitor, and monitor it as you expect**(well most of the time)
        
        ### unwatch
        
        When you are done with the variable, you can unwatch it.
        
        ```python
        from watchpoints import watch, unwatch
        
        a = 0
        watch(a)
        a = 1
        unwatch(a)
        a = 2  # nothing will happen
        ```
        
        Or you can unwatch everything by passing no argument to it
        
        ```python
        unwatch()  # unwatch everything
        ```
        
        ### alias
        
        You can give an alias to a monitored variable, so you can unwatch it anywhere. And the alias will be printed instead of the variable name
        ```python
        from watchpoints import watch, unwatch
        
        watch(a, alias="james")
        # Many other stuff, scope changes
        unwatch("james")
        ```
        
        ### variable vs object
        
        When you do ```watch()``` on an object, you are actually tracking both the object and the variable holding it. In most cases, that's what
        you want anyways. However, you can configure precisely which you want to track.
        
        ```python
        a = []
        watch(a, track="object")
        a.append(1)  # Trigger
        a = {}  # Won't trigger because the list object does not change
        
        a = []
        watch(a, track="variable")
        a.append(1)  #  Won't trigger, because "a" still holds the same object
        a = {}  # Trigger
        ```
        
        This is helpful for a customize object. The way watchpoints tracks objects is to do a deepcopy and compare the current one to the copied
        one previously. However, the default ```__eq__``` function compares if they are the "same" object.
        
        ```python
        a = MyObj()
        watch(a)
        b = 0  # Trigger because the object "a" holds is "different" than the copied one
        ```
        
        ```python
        a = MyObj()
        watch(a, track="variable")
        b = 0  # Won't trigger
        ```
        
        Of course, you can overload ```__eq__``` function to resolve this issue.
        
        ### customize callback
        
        Of course sometimes you want to print in your own format, or even do something more than print. You can use your own callback for monitored variables
        
        ```python
        watch(a, callback=my_callback)
        ```
        
        The callback function takes three arguments
        
        ```python
        def my_callback(frame, elem, exec_info)
        ```
        
        * ```frame``` is the current frame when a change is detected.
        * ```elem``` is a ```WatchElement``` object that I'm to lazy to describe for now.
        * ```exec_info``` is a tuple of ```(funcname, filename, lineno)``` of the line that changed the variable
        
        You can also set change the callback function globally by
        
        ```python
        watch.config(callback=my_callback)
        ```
        
        Use ```restore()``` to restore the default callback
        ```python
        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.
        
        
        ### Avoid import
        
        Sometimes it's a hassle having to import the function in every single file. You can install the watch function to builtins
        and be able to call it in any files:
        
        ```python
        watch.install()  # or watch.install("func_name") and use it as func_name()
        # Remove it from the builtins
        watch.uninstall()  # if installed with a name, pass it to uninstall() as well
        ```
        
        ## Limitations
        
        * watchpoints uses ```sys.settrace()``` so it is not compatible with other libraries that use the same function.
        * watchpoints will slow down your program significantly, like other debuggers, so use it for debugging purpose only
        * ```watch()``` needs to be used by itself, not nested in other functions, to be correctly parsed
        * Custom objects require ```__eq__``` overload to be tracked correctly as an object
        * at this point, there might be other issues because it's still in development phase
        
        ## Bugs/Requests
        
        Please send bug reports and feature requests through [github issue tracker](https://github.com/gaogaotiantian/watchpoints/issues).
        
        ## License
        
        Copyright Tian Gao, 2020.
        
        Distributed under the terms of the  [Apache 2.0 license](https://github.com/gaogaotiantian/watchpoints/blob/master/LICENSE).
Platform: UNKNOWN
Classifier: Development Status :: 3 - Alpha
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Apache Software License
Classifier: Operating System :: OS Independent
Requires-Python: >=3.6
Description-Content-Type: text/markdown
