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.
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 :
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.
