Code Documentation¶
Slicing¶
The definition of slicing is split into forward and backwards slicing: using both methods together and we get a full slice. Currently only forward slicing is implemented which returns all line numbers depending on the current line number.
Slicing Forward¶
Given a simple program:
>>> program = u"""
... def main():
... foo = 1
... bar = 1
... baz = foo + bar
... print(baz)
...
... if __name__ == "__main__":
... main()
... """
To see which lines depend on line 3, use the slice_string() method:
>>> from programslice import slice_string
>>> slice_string('foo', 3, 4, program, 'myprogram')
['foo,3,4', 'foo,5,10', 'baz,5,4', 'baz,6,10']
Shebangs and Encoding declarations¶
Sometimes programs use encoding declarations, which need to removed before the program can be parsed. The slicing will not cause an error:
>>> encprogram = u'#!/usr/bin/env python\n# -*- coding: utf-8 -*-\n{program}'.format(program=program)
>>> ignored = slice_string('bar', 4, 4, encprogram, 'myprogram')
>>> encprogram = u'#!/usr/bin/env python\n#\n# vim: set fileencoding=utf-8 :\n{program}'.format(program=program)
>>> ignored = slice_string('baz', 5, 4, encprogram, 'myprogram')
Text Output¶
Instead of returning line numbers, we can filter the buffer as well. The
slice_string function can be given a custom formatter class. It
defaults to LineFormatter to just render the line numbers:
>>> from programslice.formatter import TextOutputFormatter
>>> result = slice_string('bar', 4, 4, program, 'myprogram', formatter=TextOutputFormatter)
>>> print('\n'.join(result))
bar = 1
baz = foo + bar
print(baz)