From: Matthew Moss <matthew.moss@...>
Date: 2008-06-28T00:56:57+09:00
Subject: [QUIZ] Statistician I (#167)

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## Statistician I (#167)

This week begins a three-part quiz, the final goal to provide a little
library for parsing and analyzing line-based data. Hopefully, each portion
of the larger problem is interesting enough on its own, without being too
difficult to attempt. The first part -- this week's quiz -- will focus on
the pattern matching.

Let's look at a bit of example input:

    You wound Perl for 15 points of Readability damage.
    You wound Perl with Metaprogramming for 23 points of Usability damage.
    Your mighty blow defeated Perl.
    C++ walks into the arena.
    C++ wounds you with Compiled Code for 37 points of Speed damage.
    You wound C++ for 52 points of Usability damage.

Okay, it's silly, but it is similar to a much larger data file I'll provide
end for testing.

You should definitely note the repetitiveness: just the sort of thing that
we can automate. In fact, I've examined the input above and created three
rules (a.k.a. patterns) that match (most of) the data:

    [The ]<name> wounds you[ with <attack>] for <amount> point[s] of <kind>[
damage].
    You wound[ the] <name>[ with <attack>] for <amount> point[s] of <kind>[
damage].
    Your mighty blow defeated[ the] <name>.

There are a few guidelines about these rules:

1. Text contained within square brackets is optional.
2. A word contained in angle brackets represents a field; not a literal
match, but data to be remembered.
3. Fields are valid within optional portions.
4. You may assume that both the rules and the input lines are stripped of
excess whitespace on both ends.

Assuming the rules are in `rules.txt` and the input is in `data.txt`,
running your Ruby script as such:

    > ruby reporter.rb rules.txt data.txt

Should generate the following output:

    Rule 1: Perl, 15, Readability
    Rule 1: Perl, Metaprogramming, 23, Usability
    Rule 2: Perl
    # No Match
    Rule 0: C++, Compiled Code, 37, Speed
    Rule 1: C++, 52, Usability

    Unmatched input:
    C++ walks into the arena.

Each line of the output corresponds to a line of the input; it indicates
which rule was matched (zero-based index), and outputs the matched fields'
values. Any lines of the input that could not be matched to one of the rules
should output an "No Match" comment, with all the unmatched input records
printed in the "Unmatched input" section at the end (so the author of the
rules can extend them appropriately).

One thing you should keep in mind while working on this week's quiz is that
you want to be flexible; followup quizzes will require that you modify
things a bit.

For testing, I am providing two larger datasets: combat logs taken from Lord
of the Rings Online gameplay. There is data for a [Guardian][1] and a
[Hunter][2]; unzip before use. Both use the same ruleset:

    [The ]<name> wounds you[ with <attack>] for <amount> point[s] of <kind>[
damage].
    You are wounded for <amount> point[s] of <kind> damage.
    You wound[ the] <name>[ with <attack>] for <amount> point[s] of <kind>[
damage].
    You reflect <amount> point[s] of <kind> damage to[ the] <name>.
    You succumb to your wounds.
    Your mighty blow defeated[ the] <name>.



[1]: http://www.splatbang.com/rubyquiz/files/guardian.zip
[2]: http://www.splatbang.com/rubyquiz/files/hunter.zip



-- 
Matthew Moss <matthew.moss@gmail.com>

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