comment on

I started playing bass a while ago, and now I am getting into the music theory part. Since I got tired of figuring out the keys/modes myself, I wrote some perl to do it.

The scripts takes two command line arguments, the key and then the mode. If the key is not specified, C is assumed, and if the mode is not specified, major is assumed. See the source for valid keys.

Update: I fixed a bug in the notes array (had "G G", instead of "G G#"). Thanks for the msg jeffa.
Update Again: I fixed the bug where invalid keys/modes weren't recognized.
Yet Another Update: Added ionian (instead of just "major").

Things that still need to be fixed:

Ouput flats (b). See the first comment below. I have no idea how to do this properly, as saying something like A# or Bb is just "known", there aren't any progmatic rules for it.
Recognize flats on the command line. el-moe suggested adding "rocker keys", which have flats (Ab, Bb, Eb, Gb).

#!/usr/bin/perl

$key = uc(shift || "C");
$mode = lc(shift || "major");

@notes = qw(A A# B C C# D D# E F F# G G# A A# B C C# D D# E F F# G G#)
+;
%modes = ("major", -1, "ionian", -1, "dorian", 0, "phrygian", 1, "lydi
+an", 2, 
          "mixolydian", 3, "aeolian", 4, "locrian", 5);
@steps = qw(2 2 1 2 2 2 1);

$notematch = join "|", @notes;
if (($key !~ /($notematch)/) || !(exists $modes{$mode})) {die "Invalid
+ key or mode!\n"}


while ($notes[0] ne $key) {
       push(@notes, shift(@notes));
}

for (0 .. $modes{"$mode"}) {
       push(@steps, shift(@steps));
}

unshift(@steps, 0);

foreach $i (@steps) {
       $index += $i;
       print $notes[$index] . " ";
}
[download]

In reply to Musical key/mode finder. by IndyZ

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


The stupid question is the question not asked
	PerlMonks