Description
Reads Scala files and creates a Tuning based on them. It can also generate a Scale that includes every interval in the Tuning. See Tuning for the principle methods.
More information about the Scala file format, and a link to the scale library, can be found at:
http://www.huygens-fokker.org/scala/scl_format.html
Class Methods
.open
a more intiutive syntax for opening a Scala file
Arguments:
| path |
path to the Scala file. |
Returns:
a new Scala object
.new
open a Scala file
Arguments:
| path |
path to the Scala file. |
.update
Checks if the local copy of the scale library is the latest and downsloads a new copy if not
Arguments:
| dir |
Optionally specify a different directory DISCUSSION: Requires curl and unzip, both of which come with Mac and Linux. |
Instance Methods
.scale
Generates a Scale which contains as a degree every step in the tuning
Examples
The scale archive, and rules for formatting .scl files, are described at http://www.huygens-fokker.org/scala/scl_format.html as of Nov.11, 2005:
- The files are human readable ASCII or 8-bit character text-files.
- The file type is .scl .
- There is one scale per file.
- Lines beginning with an exclamation mark are regarded as comments and are to be ignored.
- The first (non comment) line contains a short description of the scale, preferably not exceeding 80 characters, but longer lines are possible and should not give a read error. The description is only one line. If there is no description, there should be an empty line.
- The second line contains the number of notes. This number indicates the number of lines with pitch values that follow. In principle there is no upper limit to this, but it is allowed to reject files exceeding a certain size. The lower limit is 0, which is possible since degree 0 of 1/1 is implicit. Spaces before or after the number are allowed.
- After that come the pitch values, each on a separate line, either as a ratio or as a value in cents. If the value contains a period, it is a cents value, otherwise a ratio. Ratios are written with a slash, and only one. Integer values with no period or slash should be regarded as such, for example "2" should be taken as "2/1". The highest allowed numerator or denominator is 231-1 = 2147483647. Anything after a valid pitch value should be ignored. Space or horizontal tab characters are allowed and should be ignored. Negative ratios are meaningless and should give a read error. For a description of cents, go here.
- The first note of 1/1 or 0.0 cents is implicit and not in the files.
- Files for which Scala gives Error in file format are incorrectly formatted. They should give a read error and be rejected.
So these lines are all valid pitch lines:
81/64 408.0 408. 5 -5.0 10/20 100.0 cents 100.0 C# 5/4 E\
Here is an example of a valid file:
! meanquar.scl ! 1/4-comma meantone scale. Pietro Aaron's temperament (1523) 12 ! 76.04900 193.15686 310.26471 5/4 503.42157 579.47057 696.57843 25/16 889.73529 1006.84314 1082.89214 2/1
An advise for writing a scale file: put the filename on the first line behind an exclamation mark. Then someone receiving the file and reading it knows a name under which to save it.