Python in the browser, precompiled for speed: http://www.transcrypt.org
Multiple inheritance, optional operator overloading, metaclasses, properties, class and function decorators, hierarchical modules etc.
Pure Python 3.5 syntax, using Python’s native parser
Debug directly from Python sourcecode, through integrated sourcemaps
Integrated static typechecking and minification at the tip of a command line switch
Also runs on top of node.js
Extensive documentation with many code examples
Apache 2.0 license
Pip-install and go!
Latest stable release: Athens
To obtain the latest stable release including all updates, install it from PyPi as described in the documentation.
Thanks to everyone who contributed!
Main differences with CPython
A few methods of builtin types are currently left out, especially when they (almost) duplicate functionality of other methods. Also method decorators (as opposed to function decorators and class decorators) are not supported, with the exception of @classmethod. This results from a deliberate choice to keep Transcrypt lean and fast.
Information for contributors
How to contribute
Transcrypt started out as a personal repo, owned by Jacques de Hooge. As the project caught on and the number of people contributing issues, ideas and code grew, the repo was transferred to the QQuick organisation, to be able to form a developer team on GitHub.
There was also a clear message in this: Transcrypt isn’t owned by anyone in particular. It is the collective property of everyone using it or contributing to it. At the same time the need was felt to keep a very firm grip on code quality, especially of the core.
Everything under ../transcrypt/modules/org/transcrypt plus the file ../transcrypt/__main__.py is considered to be part of Transcrypt’s core. A major design goal is to keep the core small and fast. This means that some CPython facilities were deliberately left out or simplified. Core development is still mainly done by Jacques, but with the input of many great ideas submitted as issues. If you want to improve something in the core, this is best initiated by first opening an issue for it. Opening a pull request directly can lead to disappointment, although all effort is made to take good ideas seriously.
All other parts of Transcrypt are referred to as periphery. While a good quality pull request for the periphery stands a reasonable chance of being accepted, still it is wise to start an issue beforehand, allowing coordination and preventing waste of effort.
While being open and respectful to any good ideas, the final say as to what gets in and what doesn’t, is with Jacques. So this is a dictatorial rather than a democratic project. Being a sailer himself, Jacques values the notion of having one captain on a ship. The captain doesn’t own the ship, but he serves the passengers by consulting with the crew and plotting one stable course.
Another possibility to contribute libraries to Transcrypt is by submitting them as separate packages to PyPi. In that case be sure to add the keyword Transcrypt to allow people to find your package. Making your package pip-installable will also help it to catch on. Contributing packages via PyPi of course means total freedom for the developer.
Development build status
The icon above shows the outcome of the continous integration test that is done on Linux after each commit. The test consists of running a set of testlets, systematically covering all facilities of Transcrypt. Each testlet performs an automated back to test against CPython.
The full set of testlets is described in the documentation and comes with the distribution. Since the branching model has been deliberately kept simple, continuous integration may be transiently broken. In that case you can use the latest passing version, that you’ll find by clicking on the icon above and then on ‘Build History’.
Each release, on the other hand, is preceded by at least the following tests:
The automated back to back test described above, not only on Linux but also on Windows and, in case of relevant issues, on OsX.
Automated compilation of the manual tests, human exercising of the resulting applications and a visual check of the results.
Automated compilation of the demo’s, manual exercising of the resulting applications and a visual check of the results.
A documentation build, followed by a visual sample check.
What’s new in the latest commits
Enhancement for issue #169: Add support for float(‘inf’) and float(‘-inf’)
Python 3.6 numbers with dashes added
Python 3.6 fstrings added
Travis CI test for the exceptions testlet repaired
Initial version of chapter ‘Differences with CPython’ added to docs
Travis CI activated
Procedural improvement for issue #160: Sphinx _build dir should be Git ignored (since it obscures code diffs)
Enhancement for issue #143: ‘isinstance’ deserves more compat
Enhancement for issue #149: Transpile docstrings on demand
Fix for issue #151: Problem with __include__ and special character inside js
Enhancement for issue #150: The ‘in’ operator (was O (n), is now O (1))
Enhancement for issue #147: str function should return string primitive, not ‘new String ()’
Fix for issue #145: List sorting (fails due to erroneous compare operator)
Fix for issue #144: List comprehensions and opov (don’t go well together, missing ‘this’ pointer)
Fix for issue #138: Parse error using ‘yield’ in expression, ‘send’ missing (see testlet iterators_and_generators) and the discussion at the issue.
Fix for issue #140: commandline –help / -h switch broken
Enhancement for issue #128: metaclasses (only __new__ overridable) + test case / doc example
Enhancement for issue #136: dict.get not implemented
Fix for issue #134: %= operator translated incorrectly
Enhancement for issue #130: Add pragma to optionally handle % the JS way
Fix for issue #127: Can’t use key ‘keys’ in a dict
Enhancement issue #113: Use for … of pervasively for js6 + autotest
Fix for issue #125: strings not iterable (js6 only) + autotest
Local classes now arbitrarily nestable, issue #120
Operator % has now Python rather than JS behaviour, issue #123 + autotest
Slicing bug fixed (stop beyond list end), issue #122 + autotest
Plotly.js demo added: lim (Numscrypt -> Maturity) Transcrypt + Numscrypt + Plotly = Live Science Demos in the Browser with native JS performance, all Plotly.js plot types are supported
__pragma__ (‘jskeys’/’nojskeys’) added make Plotly.js code match Plotly.js docs for convenience, locally voiding the need for quotes around dir keys
‘Star us on GitHub’ command line option added
Fix for ‘unexpected indent’ when rebuilding
Fix for accidentally deleting current path from sys.path in some installations
Fix for ‘cannot import __symbols__’ bug when using -r with autotest.
Exception hierarchy improved, all Transcrypt runtime exceptions now derive from Exception
Attempt to iterate over non-iterable now results in exception (only when using -e 6 switch) (see issue #112))
Iterating over TypedArrays and other non-list iterables fixed (only needed for when using -e 6 switch) (see issue #112)
Truthyness of instances of custom classes fixed (see issue #110)
Source map generation bug fixed (see issue #104)
Optional static type validation using mypy (experimental)
Small doc improvements
Some more fixes for Numscrypt
Fix to enable Numscrypt development
Pragma’s else and elif fixed for use in .py rather than .js files
Other packages you might like
Multi-module Python source code obfuscator: https://pypi.python.org/pypi/Opy
PLC simulator with Arduino code generation: https://pypi.python.org/pypi/SimPyLC
A lightweight Python course taking beginners seriously (under construction): https://pypi.python.org/pypi/LightOn
Event driven evaluation nodes: https://pypi.python.org/pypi/Eden
Copyright 2014, 2015, 2016 Jacques de Hooge, GEATEC engineering, www.geatec.com
Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
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