To use grec in a project:

import grec

The grec package exports the Matcher class. To prepare text colorization, create a new Matcher instance and add patterns to it:

matcher = grec.Matcher()
matcher.add_group_pattern('(ERROR):(.*)$', ['white', 'red'], ['magenta'])
matcher.add_pattern('WARN', 'yellow')
matcher.add_pattern('[0-9]', 'blue', 'white')

This instance is now ready to match for colors in strings passed to it. Do it with the match method:

result = matcher.match('ERROR: message WARN INFO 123')

The result is an instance of ColoredString. Its __str__ method will return a string with ANSI escape codes for all matched colors. Thus, the instance can simply be printed to show the text with colors in the terminal. If no patterns matched the string will be printed without color.

Another way to match is to use the match_iter method of the matcher. This method takes an iterable and will return an iterator which returns corresponding ColoredString instances for each match of the passed iterable.

lines = ['WARN 1', 'ERROR 2', 'INFO 3']
for colored_string in matcher.match_iter(lines):
    print colored_string