This is a simple glob pattern library written Go. This library is worth considering for two reasons. First, it includes the ** pattern to match directories recursively, in addition to the standard wildcard patterns ?, character classes, and *. More importantly, it's matching algorithm works in O(n) time, where n is the length of the pattern. Russ Cox showed in his article Glob Matching Can Be Simple And Fast Too that some pattern matching algorithms take exponential time.

The library handles wildcard patterns as described in the glob(7) Linux man page. In summary:

• sequences of literal characters.
• escaped special characters in a sequence (\?, \[, \*, \\).
• character classes that define sets of characters to compare against a single character in a path.
• escaped special characters in a character class (\!, \-, \], \\).
• ?: any single character except for a path separator.
• *: zero-or-more characters in a sequence except for a path separator.
• **: zero-or-more characters in a sequence, including path separators.

The API is very simple. There are just two functions, Match(patternString, pathString string) (bool, int) and Validate(pattern string) (int, error). Match accepts a glob pattern and a path. It returns a bool indicating if there was a match, and the number of characters in the path that matched. Match assumes there are no errors in the pattern. Validate can be called first to ensure the pattern has no syntax errors. It scans the pattern and returns (n, nil) on no error, where n is the number of characters in the pattern, or a non-nil error if there's an issue and the number of characters with no errors.

The tools folder contains profile.sh which generates and reports coverage data for the unit test. It also build and runs the code in cmd/main.go, which is a program that accepts a pattern and a path on the command line, validates the pattern and (if the pattern is valid) reports whether or not the path is matched with it.