1. 29 Apr, 2020 1 commit
  2. 16 Apr, 2020 1 commit
  3. 27 Feb, 2020 2 commits
  4. 17 Feb, 2020 1 commit
    • Kirill Smelkov's avatar
      sync += RWMutex · 1ad3c2d5
      Kirill Smelkov authored
      Provide sync.RWMutex that can be useful for cases when there are
      multiple simultaneous readers and more seldom writer(s).
      This implements readers-writer mutex with preference for writers
      similarly to Go version.
  5. 27 Nov, 2019 1 commit
    • Kirill Smelkov's avatar
      readme: Turn package references into links · 37ae291f
      Kirill Smelkov authored
      For base functionality we have overview in the readme itself, but for
      packages we have only their listing with brief overview and no
      documentation for in-package functionality.
      Let's have at least links to .h/.pxd/.py where package functionality is
  6. 07 Nov, 2019 2 commits
  7. 18 Oct, 2019 1 commit
    • Kirill Smelkov's avatar
      golang: Teach defer to chain exceptions (PEP 3134) even on Python2 · bb9a94c3
      Kirill Smelkov authored
      Python3 chains exceptions, so that e.g. if exc1 is raised and, while it
      was not handled, another exc2 is raised, exc2 will be linked to exc1 via
      exc2.__context__ attribute and exc1 will be included into exc2 traceback
      printout. However many projects still use Python2 and there is no
      similar chaining functionality there. This way exc1 is completely lost.
      Since defer code is in our hands, we can teach it to implement exception
      chaining even on Python2 by carefully analyzing what happens in
      Implementing chaining itself is relatively easy, but is only part of the
      story. Even if an exception is chained with its cause, but exception
      dump does not show the cause, the chaining will be practically useless.
      With this in mind this patches settles not only on implementing chaining
      itself, but on also giving a promise that chained cause exceptions will
      be included into traceback dumps as well.
      To realize this promise we adjust all exception dumping funcitons in
      traceback module and carefully install adjusted
      traceback.print_exception() into sys.excepthook. This amends python
      interactive sessions and programs run by python interpreter to include
      causes in exception dumps. "Careful" here means that we don't change
      sys.excepthook if on golang module load we see that sys.excepthook was already
      changed by some other module - e.g. due to IPython session running
      because IPython installs its own sys.excepthook. In such cases we don't
      install our sys.excepthook, but we also provide integration patches that
      add exception chaining support for traceback dump functionality in
      popular third-party software. The patches (currently for IPython and
      Pytest) are activated automatically, but only when/if corresponding
      software is imported and actually used. This should give practically
      good implementation of the promise - a user can now rely on seeing
      exception cause in traceback dump whatever way python programs are run.
      The implementation takes https://pypi.org/project/pep3134/ experience
      into account [1]. peak.utils.imports [2,3] is used to be notified when/if
      third-party module is imported.
      [1] https://github.com/9seconds/pep3134/
      [2] https://pypi.org/project/Importing/
      [3] http://peak.telecommunity.com/DevCenter/Importing
      This patch originally started as hacky workaround in wendelin.core
      because in wcfs tests I was frequently hitting situations, where
      exception raised by an assert was hidden by another exception raised in
      further generic teardown check. For example wcfs tests check that wcfs
      is unmounted after every test run [4] and if that fails it was hiding
      problems raised by an assert. As the result I was constantly guessing
      and adding code like [5] to find what was actually breaking. At some
      point I added hacky workaround for defer to print cause exception not to
      loose it [6]. [7] has more context and background discussion on this topic.
      [4] https://lab.nexedi.com/kirr/wendelin.core/blob/49e73a6d/wcfs/wcfs_test.py#L70
      [5] https://lab.nexedi.com/kirr/wendelin.core/blob/49e73a6d/wcfs/wcfs_test.py#L853-857
      [6] kirr/wendelin.core@c00d94c7
      [7] zodbtools!13 (comment 81553)
      After this patch, on Python2
      is no longer just a syntatic sugar for
  8. 14 Oct, 2019 2 commits
    • Kirill Smelkov's avatar
      golang: Teach pychan to work with channels of C types, not only PyObjects · 3121b290
      Kirill Smelkov authored
      Introduce notion of data type (dtype similarly to NumPy) into pychan and
      teach it to accept for send objects only matching that dtype. Likewise
      teach pychan to decode raw bytes received from underlying channel into
      Python object correspodningg to pychan dtype. For C dtypes, e.g.
      'C.int', 'C.double' etc, contrary to chan of python objects, the
      transfer can be done without depending on Python GIL. This way channels
      of such C-level dtypes can be used to implement interaction in between
      Python and nogil worlds.
    • Kirill Smelkov's avatar
      *: Channels must be compared by ==, not by "is" even for nilchan · 2c8063f4
      Kirill Smelkov authored
      In a followup commit we are going to add channel types (e.g. chan of
      double, chan of int, etc) and accordingly there will be several nil
      channel objects, e.g. nil(dtype=int), nil(dtype=double) etc, which will
      be separate python objects. Even without data types, another planned
      change is to add directional channels, e.g. a channel instance that can
      only send, but not receive and vice versa(*).
      This way for the same underlying channel object, there can be several
      pychan objects that point to it - even for nil channel - e.g. nilchan
      and `niltx = nilchan.txonly()` that creates another pychan object
      pointing to the same underlying nil.
      Since we want all channels (of the same type) that point to the same
      underlying channel to compare as same, we cannot use "is" for comparison
      and have to use ==. In other words channels, both at C and Python level,
      should be perceived as pointers, of which there can be multiple ones
      pointing to the same location, and thus == has to be used to compare
      (*) see https://golang.org/ref/spec#Channel_types for details.
  9. 04 Oct, 2019 1 commit
    • Kirill Smelkov's avatar
      golang: Expose Sema and Mutex as public Python and Cython/nogil API · 34b7a1f4
      Kirill Smelkov authored
      Until now libgolang had semaphore and mutex functionality, but
      implemented only internally and not exposed to users. Since for its
      pinner thread wendelin.core v2 needs not only nogil channels, but also
      nogil mutexes, timers and so on, it is now time to start providing that.
      We start with mutexes:
      - Expose Mutex from insides of libgolang.cpp to public API in
        libgolang.h . We actually expose both Mutex and Sema because
        semaphores are sometimes also useful for low-level synchronization,
        and because it is easier to export Mutex and Sema both at the same time.
      - Provide pyx/nogil API to those as sync.Mutex and sync.Sema.
      - Provide corresponding python wrappers.
      - Add Pyx-level test for semaphore wakeup when wakeup is done not by the
        same thread which did the original acquire. This is the test that was
        promised in 5142460d (libgolang/thread: Add links to upstream
        PyThread_release_lock bug), and it used to corrupt memory and deadlock
        on macOS due to CPython & PyPy runtime bugs:
            -> https://github.com/python/cpython/pull/16047
      Note about python wrappers: At present, due to
      https://github.com/cython/cython/issues/3165, C-level panic is not
      properly translated into Py-level exception in (Py)Sema/Mutex constructors.
      This should not pose a real problem in practice though.
  10. 29 Aug, 2019 4 commits
    • Kirill Smelkov's avatar
      pygolang v0.0.3 · 4ca65816
      Kirill Smelkov authored
    • Kirill Smelkov's avatar
      Port/move channels to C/C++/Pyx · 3b241983
      Kirill Smelkov authored
      - Move channels implementation to be done in C++ inside libgolang. The
        code and logic is based on previous Python-level channels
        implementation, but the new code is just C++ and does not depend on
        Python nor GIL at all, and so works without GIL if libgolang
        runtime works without GIL(*).
        (*) for example "thread" runtime works without GIL, while "gevent" runtime
            acquires GIL on every semaphore acquire.
        New channels implementation is located in δ(libgolang.cpp).
      - Provide low-level C channels API to the implementation. The low-level
        C API was inspired by Libtask[1] and Plan9/Libthread[2].
        [1] Libtask: a Coroutine Library for C and Unix. https://swtch.com/libtask.
        [2] http://9p.io/magic/man2html/2/thread.
      - Provide high-level C++ channels API that provides type-safety and
        automatic channel lifetime management.
        Overview of C and C++ APIs are in δ(libgolang.h).
      - Expose C++ channels API at Pyx level as Cython/nogil API so that Cython
        programs could use channels with ease and without need to care about
        lifetime management and low-level details.
        Overview of Cython/nogil channels API is in δ(README.rst) and
      - Turn Python channels to be tiny wrapper around chan<PyObject>.
      Implementation note:
      - gevent case needs special care because greenlet, which gevent uses,
        swaps coroutine stack from C stack to heap on coroutine park, and
        replaces that space on C stack with stack of activated coroutine
        copied back from heap. This way if an object on g's stack is accessed
        while g is parked it would be memory of another g's stack.
        The channels implementation explicitly cares about this issue so that
        stack -> * channel send, or * -> stack channel receive work correctly.
        It should be noted that greenlet approach, which it inherits from
        stackless, is not only a bit tricky, but also comes with overhead
        (stack <-> heap copy), and prevents a coroutine to migrate from 1 OS
        thread to another OS thread as that would change addresses of on-stack
        things for that coroutine.
        As the latter property prevents to use multiple CPUs even if the
        program / runtime are prepared to work without GIL, it would be more
        logical to change gevent/greenlet to use separate stack for each
        coroutine. That would remove stack <-> heap copy and the need for
        special care in channels implementation for stack - stack sends.
        Such approach should be possible to implement with e.g. swapcontext or
        similar mechanism, and a proof of concept of such work wrapped into
        greenlet-compatible API exists[3]. It would be good if at some point
        there would be a chance to explore such approach in Pygolang context.
        [3] https://github.com/python-greenlet/greenlet/issues/113#issuecomment-264529838 and below
      Just this patch brings in the following speedup at Python level:
       (on i7@2.6GHz)
      thread runtime:
          name             old time/op  new time/op  delta
          go               20.0µs ± 1%  15.6µs ± 1%  -21.84%  (p=0.000 n=10+10)
          chan             9.37µs ± 4%  2.89µs ± 6%  -69.12%  (p=0.000 n=10+10)
          select           20.2µs ± 4%   3.4µs ± 5%  -83.20%  (p=0.000 n=8+10)
          def              58.0ns ± 0%  60.0ns ± 0%   +3.45%  (p=0.000 n=8+10)
          func_def         43.8µs ± 1%  43.9µs ± 1%     ~     (p=0.796 n=10+10)
          call             62.4ns ± 1%  63.5ns ± 1%   +1.76%  (p=0.001 n=10+10)
          func_call        1.06µs ± 1%  1.05µs ± 1%   -0.63%  (p=0.002 n=10+10)
          try_finally       136ns ± 0%   137ns ± 0%   +0.74%  (p=0.000 n=9+10)
          defer            2.28µs ± 1%  2.33µs ± 1%   +2.34%  (p=0.000 n=10+10)
          workgroup_empty  48.2µs ± 1%  34.1µs ± 2%  -29.18%  (p=0.000 n=9+10)
          workgroup_raise  58.9µs ± 1%  45.5µs ± 1%  -22.74%  (p=0.000 n=10+10)
      gevent runtime:
          name             old time/op  new time/op  delta
          go               24.7µs ± 1%  15.9µs ± 1%  -35.72%  (p=0.000 n=9+9)
          chan             11.6µs ± 1%   7.3µs ± 1%  -36.74%  (p=0.000 n=10+10)
          select           22.5µs ± 1%  10.4µs ± 1%  -53.73%  (p=0.000 n=10+10)
          def              55.0ns ± 0%  55.0ns ± 0%     ~     (all equal)
          func_def         43.6µs ± 1%  43.6µs ± 1%     ~     (p=0.684 n=10+10)
          call             63.0ns ± 0%  64.0ns ± 0%   +1.59%  (p=0.000 n=10+10)
          func_call        1.06µs ± 1%  1.07µs ± 1%   +0.45%  (p=0.045 n=10+9)
          try_finally       135ns ± 0%   137ns ± 0%   +1.48%  (p=0.000 n=10+10)
          defer            2.31µs ± 1%  2.33µs ± 1%   +0.89%  (p=0.000 n=10+10)
          workgroup_empty  70.2µs ± 0%  55.8µs ± 0%  -20.63%  (p=0.000 n=10+10)
          workgroup_raise  90.3µs ± 0%  70.9µs ± 1%  -21.51%  (p=0.000 n=9+10)
      The whole Cython/nogil work - starting from 8fa3c15b (Start using Cython
      and providing Cython/nogil API) to this patch - brings in the following
      speedup at Python level:
       (on i7@2.6GHz)
      thread runtime:
          name             old time/op  new time/op  delta
          go               92.9µs ± 1%  15.6µs ± 1%  -83.16%  (p=0.000 n=10+10)
          chan             13.9µs ± 1%   2.9µs ± 6%  -79.14%  (p=0.000 n=10+10)
          select           29.7µs ± 6%   3.4µs ± 5%  -88.55%  (p=0.000 n=10+10)
          def              57.0ns ± 0%  60.0ns ± 0%   +5.26%  (p=0.000 n=10+10)
          func_def         44.0µs ± 1%  43.9µs ± 1%     ~     (p=0.055 n=10+10)
          call             63.5ns ± 1%  63.5ns ± 1%     ~     (p=1.000 n=10+10)
          func_call        1.06µs ± 0%  1.05µs ± 1%   -1.31%  (p=0.000 n=10+10)
          try_finally       139ns ± 0%   137ns ± 0%   -1.44%  (p=0.000 n=10+10)
          defer            2.36µs ± 1%  2.33µs ± 1%   -1.26%  (p=0.000 n=10+10)
          workgroup_empty  98.4µs ± 1%  34.1µs ± 2%  -65.32%  (p=0.000 n=10+10)
          workgroup_raise   135µs ± 1%    46µs ± 1%  -66.35%  (p=0.000 n=10+10)
      gevent runtime:
          name             old time/op  new time/op  delta
          go               68.8µs ± 1%  15.9µs ± 1%  -76.91%  (p=0.000 n=10+9)
          chan             14.8µs ± 1%   7.3µs ± 1%  -50.67%  (p=0.000 n=10+10)
          select           32.0µs ± 0%  10.4µs ± 1%  -67.57%  (p=0.000 n=10+10)
          def              58.0ns ± 0%  55.0ns ± 0%   -5.17%  (p=0.000 n=10+10)
          func_def         43.9µs ± 1%  43.6µs ± 1%   -0.53%  (p=0.035 n=10+10)
          call             63.5ns ± 1%  64.0ns ± 0%   +0.79%  (p=0.033 n=10+10)
          func_call        1.08µs ± 1%  1.07µs ± 1%   -1.74%  (p=0.000 n=10+9)
          try_finally       142ns ± 0%   137ns ± 0%   -3.52%  (p=0.000 n=10+10)
          defer            2.32µs ± 1%  2.33µs ± 1%   +0.71%  (p=0.005 n=10+10)
          workgroup_empty  90.3µs ± 0%  55.8µs ± 0%  -38.26%  (p=0.000 n=10+10)
          workgroup_raise   108µs ± 1%    71µs ± 1%  -34.64%  (p=0.000 n=10+10)
      This patch is the final patch in series to reach the goal of providing
      channels that could be used in Cython/nogil code.
      Cython/nogil channels work is dedicated to the memory of Вера Павловна Супрун[4].
      [4] https://navytux.spb.ru/memory/%D0%A2%D1%91%D1%82%D1%8F%20%D0%92%D0%B5%D1%80%D0%B0.pdf#page=3
    • Kirill Smelkov's avatar
      pyx api: Provide go · f971a2a8
      Kirill Smelkov authored
      - Add go functionality to libgolang runtime;
      - Implement go for thread and gevent runtimes.
        * Thread runtime uses PyThread_start_new_thread which, if used
          carefully, does not depend on Python GIL and on e.g. POSIX reduces to
          tiny wrapper around pthread_create.
        * Gevent runtime uses gevent's Greenlet in Pyx mode. This turns
          gevent to be a build-time dependency.
      - Provide low-level _taskgo in C client API;
      - Provide type-safe C++-level go wrapper over _taskgo;
      - Switch golang.go from py implementation into Pyx wrapper over
        Pyx/nogil API.
      This is the first patch that adds Pyx/C++/C-level unit tests and hooks
      them into golang_test.py .
      This patch brings the following speedup to Python-level interface:
       (on i7@2.6GHz)
      thread runtime:
          name             old time/op  new time/op  delta
          go               93.0µs ± 1%  26.6µs ± 1%  -71.41%  (p=0.000 n=10+10)
          chan             13.6µs ± 2%  13.7µs ± 1%     ~     (p=0.280 n=10+10)
          select           29.9µs ± 4%  29.3µs ± 2%   -1.89%  (p=0.017 n=10+9)
          def              61.0ns ± 0%  55.0ns ± 0%   -9.84%  (p=0.000 n=10+10)
          func_def         43.8µs ± 1%  44.0µs ± 1%   +0.66%  (p=0.006 n=10+10)
          call             62.5ns ± 1%  64.0ns ± 0%   +2.40%  (p=0.000 n=10+8)
          func_call        1.06µs ± 1%  1.09µs ± 1%   +2.72%  (p=0.000 n=10+10)
          try_finally       137ns ± 0%   139ns ± 2%   +1.17%  (p=0.033 n=10+10)
          defer            2.34µs ± 1%  2.36µs ± 1%   +0.84%  (p=0.015 n=10+10)
          workgroup_empty  96.1µs ± 1%  58.1µs ± 1%  -39.55%  (p=0.000 n=10+10)
          workgroup_raise   135µs ± 1%    73µs ± 1%  -45.97%  (p=0.000 n=10+10)
      gevent runtime:
          name             old time/op  new time/op  delta
          go               68.8µs ± 1%  28.6µs ± 0%  -58.47%  (p=0.000 n=10+8)
          chan             14.8µs ± 1%  15.8µs ± 1%   +6.19%  (p=0.000 n=10+10)
          select           32.0µs ± 0%  33.1µs ± 1%   +3.25%  (p=0.000 n=10+10)
          def              58.0ns ± 0%  55.0ns ± 0%   -5.17%  (p=0.000 n=10+10)
          func_def         43.9µs ± 1%  44.4µs ± 2%   +1.20%  (p=0.007 n=10+10)
          call             63.5ns ± 1%  64.0ns ± 2%     ~     (p=0.307 n=10+10)
          func_call        1.08µs ± 1%  1.06µs ± 0%   -2.55%  (p=0.000 n=10+8)
          try_finally       142ns ± 0%   136ns ± 0%   -4.23%  (p=0.000 n=10+9)
          defer            2.32µs ± 1%  2.29µs ± 1%   -0.96%  (p=0.000 n=10+10)
          workgroup_empty  90.3µs ± 0%  73.8µs ± 1%  -18.29%  (p=0.000 n=10+10)
          workgroup_raise   108µs ± 1%    94µs ± 0%  -13.29%  (p=0.000 n=10+10)
      (small changes are probably within noise; "go" and "workgroup_*" should be
    • Kirill Smelkov's avatar
      Start using Cython and providing Cython/nogil API · 8fa3c15b
      Kirill Smelkov authored
      Start transforming Pygolang from being pure Python project into project
      that uses both Python and Cython and provides both Python and Cython API
      to its users.
      For Cython API there is a goal for it to be usable independently of
      Python GIL - i.e. independently of Python runtime and limitations
      imposed by Python's global interpreter lock. The motivation for this
      work is wendelin.core v2, which, due to its design, would deadlock if it
      tries to take the GIL in its pinner thread.
      This commit brings bare minimum establishing libraries and build system.
      - Introduces C/C++ library libgolang. Libgolang will be serving most of
        nogil functionality and Pyx API will be a small wrapper over it. At
        this step Libgolang comes only with C-level panic;
      - Introduces Pyx package golang that is aliased to Pyx package
        golang._golang . Users can do `from golang cimport ...` similarly to how
        they do py-level `from golang import ...`. At this step golang.pyx
        only wraps panic and provides way to transform C-level panic into Python
      - Introduces Py package golang.pyx.build . This package, similarly to
        golang.org/pkg/go/build, serves as the system to build Pyx packages -
        both external packages that use Pygolang in pyx mode, and to build
        Pygolang itself. The build, internally, is served by setuptools_dso
        and cython. An example how to use golang.pyx.build from external
        project comes in golang/pyx/testprog/golang_pyx_user/ and is used by
        tests to verify golang.pyx.build functionality;
      - Introduces Pygolang build dependency to cython and setuptools_dso.
  11. 16 May, 2019 3 commits
    • Kirill Smelkov's avatar
      pygolang v0.0.2 · d3bfb1bf
      Kirill Smelkov authored
    • Kirill Smelkov's avatar
      context: Add support for deadlines · b2450310
      Kirill Smelkov authored
      Implement deadlines / timeouts using timers added recently in 9c260fde
      (time: New package that mirrors Go's time).
    • Kirill Smelkov's avatar
      time: New package that mirrors Go's time · 9c260fde
      Kirill Smelkov authored
      Add time.Timer, time.Ticker and convenience functions time.tick,
      time.after and time.after_func. These will be used in context to support
      deadlines and timeouts.
      While at time topic, also provide sleep and now from golang.time, so
      that there is no need to import both golang.time and stdlib's time in a
      Provide time constants in the module as they are useful to have and
      mirror constants provided by Go's time.
      Note: timers implementation is very suboptimal for now.
  12. 10 May, 2019 1 commit
    • Kirill Smelkov's avatar
      fixup! pygolang v0.0.1 · 1172e39f
      Kirill Smelkov authored
      - correct CHANGELOG title levels: since readme uses "----" for the
        first level and "~~~~" for the second level, "====" was interpreted as
        the third title level and "Pygolang change history" became
        sub-sub-section of "Additional packages and utilities" with section
        for each version conversely becoming first level. It was not very
        noticeable until 0c5f9d06 (readme: Push "Additional packages and
        utilities" into its own section) started to use "~~~~".
        -> Rework CHANGELOG titling to align with the one in README.
      - fix minor markup bits in README.
  13. 03 May, 2019 3 commits
  14. 02 May, 2019 2 commits
    • Kirill Smelkov's avatar
      readme: Push "Additional packages and utilities" into its own section · 0c5f9d06
      Kirill Smelkov authored
      We are going to add more packages to mirror Go stdlib (e.g. next is
      context). Organize a dedicated section for what is additionally provided
      besides mirroring Go language and refer to that place only once from the
      top-level abstract.
    • Kirill Smelkov's avatar
      golang: Add support for nil channel · 2aad64bb
      Kirill Smelkov authored
      Send/recv on the nil channel block forever; close panics.
      If a nil channel is used in select - corresponding case is never selected.
      Setting channel to nil is a usual idiom in Go to disable processing some
      cases in select. Nil channel is also used as "done" for e.g.
      context.Background() - for contexts that can be never canceled.
  15. 24 Mar, 2019 1 commit
  16. 15 Mar, 2019 1 commit
    • Kirill Smelkov's avatar
      golang: Deprecate @method(cls) in favour of @func(cls) · 942ee900
      Kirill Smelkov authored
      Since we already have func (see 5146eb0b "Add support for defer &
      recover") we can use @func for both plain functions and for methods.
      For example instead of
      	def my_function(...):
      	@method(MyClass)			<-- NOTE
      	def my_method(self, ...):
      have it as
      	def my_function(...):
      	@func(MyClass)				<-- NOTE
      	def my_method(self, ...):
      which looks more similar to Go and exposes less golang keywords to a user.
  17. 16 Jan, 2019 1 commit
  18. 13 Dec, 2018 3 commits
    • Kirill Smelkov's avatar
      strconv += unquote(), unquote_next() · ed6b7895
      Kirill Smelkov authored
      This are functions to decode quotation that was produced by
    • Kirill Smelkov's avatar
      strconv: New package + expose .quote() there · f09701b0
      Kirill Smelkov authored
      Move quote implementation from gcompat to strconv. Make quote work on both
      unicode|bytes string input and produce the same output type. Preserve qq
      (still remaining in gcompat) to always produce str, since that is used
      in prints.
    • Kirill Smelkov's avatar
      readme: Overhaul · 94bae8e8
      Kirill Smelkov authored
      Stop hiding qq and benchmarking bits in changelog only - add their
      description into additional sections in readme.
      Since py.bench description is now in readme, there is no need to keep
      py.bench example in the changelog.
  19. 30 Oct, 2018 1 commit
    • Kirill Smelkov's avatar
      Add support for defer & recover · 5146eb0b
      Kirill Smelkov authored
      `defer` allows to schedule a cleanup to be executed when current function
      returns. It is similar to `try`/`finally` but does not force the cleanup part
      to be far away in the end. For example::
         wc = wcfs.join(zurl)    │     wc = wcfs.join(zurl)
         defer(wc.close)         │     try:
                                 │        ...
         ...                     │        ...
         ...                     │        ...
         ...                     │     finally:
                                 │        wc.close()
      For completeness there is `recover` and `panic` that allow to program with
      Go-style error handling, for example::
         def _():
            r = recover()
            if r is not None:
               print("recovered. error was: %s" % (r,))
      But `recover` and `panic` are probably of less utility since they can be
      practically natively modelled with `try`/`except`.
      If `defer` is used, the function that uses it must be wrapped with `@func` or
      `@method` decorators.
      The implementation is partly inspired by work of Denis Kolodin:
      - https://habr.com/post/191786
      - https://stackoverflow.com/a/43028386/9456786
  20. 20 Jun, 2018 1 commit
    • Kirill Smelkov's avatar
      Turn pygopath into full pygolang · afa46cf5
      Kirill Smelkov authored
      Not only we can import modules by full path, but now we can also spawn
      threads/coroutines and exchange data in between them with the same
      primitives and semantic as in Go.
      The bulk of new functionality is copied from here:
      Original commit description follows:
      golang: New _Python_ package to provide Go-like features to Python language
      - `go` spawns lightweight thread.
      - `chan` and `select` provide channels with Go semantic.
      - `method` allows to define methods separate from class.
      - `gimport` allows to import python modules by full path in a Go workspace.
      The focus of first draft was on usage interface and on correctness, not speed.
      In particular select should be fully working.
      If there is a chance I will maybe try to followup with gevent-based
      implementation in the future.
      Hide whitespace changes
  21. 21 May, 2018 1 commit
    • Kirill Smelkov's avatar
      pygopath: Initial draft · 9c61f254
      Kirill Smelkov authored
      Module gopath provides way to import python modules by full path in a Go workspace.
      For example
          lonet = gopath.gimport('lab.nexedi.com/kirr/go123/xnet/lonet')
      will import either
          lab.nexedi.com/kirr/go123/xnet/lonet.py, or
      located somewhere under $GOPATH.