Massedit
Programmatically edit text files with Python. Useful for source to source transformations.
Install / Use
/learn @elmotec/MasseditREADME
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======== massedit
formerly known as Python Mass Editor
Implements a python mass editor to process text files using Python code. The modification(s) is (are) shown on stdout as a diff output. One can then modify the target file(s) in place with the -w/--write option. This is very similar to 2to3 tool that ships with Python 3.
+--------------------------------------------------------------------------+
| WARNING: A word of caution about the usage of eval() |
+--------------------------------------------------------------------------+
| This tool is useful as far as it goes but it does rely on the python |
| eval() function and does not check the code being executed. |
| It is a major security risk and one should not use this tool in a |
| production environment. |
| |
| See Ned Batchelder's article_ for a thorough discussion of the dangers |
| linked to eval() and ways to circumvent them. Note that None of the |
| counter-measure suggested in the article are implemented at this time. |
+--------------------------------------------------------------------------+
Usage
You probably will need to know the basics of the Python re module_ (regular
expressions).
::
usage: massedit.py [-h] [-V] [-w] [-v] [-e EXPRESSIONS] [-f FUNCTIONS]
[-x EXECUTABLES] [-s START_DIRS] [-m MAX_DEPTH] [-o FILE]
[-g FILE] [--encoding ENCODING] [--newline NEWLINE]
[file pattern [file pattern ...]]
Python mass editor
positional arguments:
file pattern shell-like file name patterns to process or - to read
from stdin.
optional arguments:
-h, --help show this help message and exit
-V, --version show program's version number and exit
-w, --write modify target file(s) in place. Shows diff otherwise.
-v, --verbose increases log verbosity (can be specified multiple
times)
-e EXPRESSIONS, --expression EXPRESSIONS
Python expressions applied to target files. Use the
line variable to reference the current line.
-f FUNCTIONS, --function FUNCTIONS
Python function to apply to target file. Takes file
content as input and yield lines. Specify function as
[module]:?<function name>.
-x EXECUTABLES, --executable EXECUTABLES
Python executable to apply to target file.
-s START_DIRS, --start START_DIRS
Directory(ies) from which to look for targets.
-m MAX_DEPTH, --max-depth-level MAX_DEPTH
Maximum depth when walking subdirectories.
-o FILE, --output FILE
redirect output to a file
-g FILE, --generate FILE
generate stub file suitable for -f option
--encoding ENCODING Encoding of input and output files
--newline NEWLINE Newline character for output files
Examples:
# Simple string substitution (-e). Will show a diff. No changes applied.
massedit.py -e "re.sub('failIf', 'assertFalse', line)" *.py
# File level modifications (-f). Overwrites the files in place (-w).
massedit.py -w -f fixer:fixit *.py
# Will change all test*.py in subdirectories of tests.
massedit.py -e "re.sub('failIf', 'assertFalse', line)" -s tests test*.py
# Will transform virtual methods (almost) to MOCK_METHOD suitable for gmock (see https://github.com/google/googletest).
massedit.py -e "re.sub(r'\s*virtual\s+([\w:<>,\s&*]+)\s+(\w+)(\([^\)]*\))\s*((\w+)*)(=\s*0)?;', 'MOCK_METHOD(\g<1>, \g<2>, \g<3>, (\g<4>, override));', line)" gmock_test.cpp
If massedit is installed as a package (from pypi for instance), one can interact with it as a command line tool:
::
python -m massedit -e "re.sub('assertEquals', 'assertEqual', line)" test.py
Or as a library (command line option above to be passed as kewyord arguments):
::
import massedit filenames = ['massedit.py'] massedit.edit_files(filenames, ["re.sub('Jerome', 'J.', line)"])
Lastly, there is a convenient massedit.bat wrapper for Windows included in
the distribution.
Installation
Download massedit.py from http://github.com/elmotec/massedit or :
::
python -m pip install massedit
Poor man source-to-source manipulation
I find myself using massedit mostly for source to source modification of large code bases like this:
First create a fixer.py python module with the function that will
process your source code. For instance, to add a header:
::
def add_header(lines, file_name): yield '// This is my header' # will be the first line of the file. for line in lines: yield line
Adds the location of fixer.py to your $PYTHONPATH, then simply
call massedit.py like this:
::
massedit.py -f fixer:add_header *.h
You can add the -s . option to process all the .h files reccursively.
Plans
- Add support for 3rd party tool (e.g.
autopep8_) to process the files. - Add support for a file of expressions as an argument to allow multiple modification at once.
- Find a satisfactory way (ie. easy to use) to handle multiline regex as the current version works on a line by line basis.
Rationale
- I have a hard time practicing more than a few dialects of regular expressions.
- I need something portable to Windows without being bothered by eol.
- I believe Python is the ideal tool to build something more powerful than simple regex based substitutions.
Background
I have been using runsed and checksed (from Unix Power Tools) for years and did not find a good substitute under Windows until I came across Graham Fawcett python recipe 437932_ on ActiveState. It inspired me to write the massedit.
The core was fleshed up a little, and here we are. If you find it useful and enhance it please, do not forget to submit patches. Thanks!
If you are more interested in awk-like tool, you probably will find pyp_ a better alternative.
Contributing
To set things up for development, please pip-install massedit as shown below. It will install it in editable mode and the develop extra packages, including commitizen that is recommended to have commits follow conventional commits convention:
::
python -m venv venv
. venv/bin/activate
python -m pip install -e .[develop,test]
License
Licensed under the term of MIT License_. See attached file LICENSE.txt.
Changes
See CHANGELOG.md for changes later than 0.69.0
0.69.1 (2023-09-10) Updated infrastructure files to setup.cfg/pyproject.toml instead of setup.py. Thanks @isidroas.
0.69.0 (2020-12-22) Also moved CI to github workflows from travis and added regression tests for Python 2.7.
0.68.6 (2019-12-02) Added support for Python 3.8, stdin input via - argument. Documented regex to turn base classes into googlemock MOCK_METHOD.
0.68.5 (2019-04-13) Added --newline option to force newline output. Thanks @ALFNeT!
0.68.4 (2017-10-24) Fixed bug that would cause changes to be missed when the -w option is ommited. Thanks @tgoodlet!
0.68.3 (2017-09-20) Added --generate option to quickly generate a fixer.py template file to be modified to be used with -f fixer.fixit option. Added official support for Python 3.6
0.68.1 (2016-06-04) Fixed encoding issues when processing non-ascii files. Added --encoding option to force the value of the encoding if need be. Listed support for Python 3.5
0.67.1 (2015-06-28) Documentation fixes.
0.67 (2015-06-23) Added file_name argument to processing functions. Fixed incorrect closing of sys.stdout/stderr. Improved diagnostic when the processing function does not take 2 arguments. Swapped -v and -V option to be consistent with Python. Pylint fixes. Added support for Python 3.4. Dropped support for Python 3.2.
0.66 (2013-07-14) Fixed lost executable bit with -f option (thanks myint).
0.65 (2013-07-12) Added -f option to execute code in a separate file/module. Added Travis continuous integration (thanks myint). Fixed python 2.7 support (thanks myint).
0.64 (2013-06-01) Fixed setup.py so that massedit installs as a script. Fixed eol issues (thanks myint).
0.63 (2013-05-27) Renamed to massedit. Previous version are still known as Python-Mass-Editor.
0.62 (2013-04-11) Fixed bug that caused an EditorError to be raised when the result of the expression is an empty string.
0.61 (2012-07-06) Added massedit.edit_files function to ease usage as library instead of as
