dilla-expressions

    2.1.3 • Public • Published

    dilla-expressions

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    expand expressions for repeating notes into flat positions

    Built for and used in dilla and bap, by Adam Renklint

    Install

    $ npm install --save dilla-expressions
    

    Usage

    var expr = require('dilla-expressions');
     
    var notes = [
      ['*.even.01']
    ];
     
    var expanded = expr(notes, {
      'barsPerLoop': 2,
      'beatsPerBar': 4
    });
     
    expect(expanded.length).to.equal(4);
    expect(expanded[0][0]).to.equal('1.2.01');
    expect(expanded[1][0]).to.equal('1.4.01');
    expect(expanded[2][0]).to.equal('2.2.01');
    expect(expanded[3][0]).to.equal('2.4.01');

    Operators

    Wildcard

    > "*.*.32"
    = "1.1.32", "1.2.32", "1.3.32", "1.4.32", "2.1.32", "2.2.32", "2.3.32", "2.4.32"

    Odd/even

    > "1.even.01"
    = "1.2.01", "1.4.01"
     
    > "1.odd.01"
    = "1.1.01", "1.1.01"

    Modulus

    > "1.%3.%30"
    = "1.1.01", "1.1.31", "1.1.61", "1.1.91", "1.4.01", "1.4.31", "1.4.61", "1.4.91"
     
    > "1.1.5%20"
    = "1.1.05", "1.1.25", "1.1.45", "1.1.65", "1.1.85"

    Greater than

    > "1.>2.01"
    = "1.3.01", "1.4.01"

    Less than

    > "1.<4.01"
    = "1.1.01", "1.2.01", "1.3.01"

    Custom expander

    It is possible to extend dilla-expressions with your own expression expander.

    The position is split into three fragments. An expander function will be called for each fragment of the position expression that is not a simple number or already expanded by a previous expander, i.e. wildcard, modulus, etc...

    Start and end represent the start and endpoints for the current fragment, and would most times be the same as barsPerLoop, but could be another value if the fragment is combined with the greater than or less than operators.

    var expanded = expr([
      ['foo.bar.baz']
    ], {
      'barsPerLoop': 2,
      'beatsPerBar': 4,
      'expander': function (fragment, start, end) {
        if (fragment === 'foo') { return [1, 2]; }
        else if (fragment === 'bar') { return [end/2]; }
        else if (fragment === 'baz') { return [15]; }
      }
    });
     
    expect(expanded.length).to.equal(2);
    expect(expanded[0][0]).to.equal('1.2.15');
    expect(expanded[1][0]).to.equal('2.2.15');

    Develop

    • make test
    • make coverage
    • make publish

    Changelog

    • 1.0.0
      • Initial release with wildcard (*), even and odd expression operators
    • 1.0.1
      • CHANGED: events are now called notes dilla/8
    • 1.1.0
      • CHANGED: expects options object instead of barsPerLoop and beatsPerBar separately #4
      • NEW: possible to add custom matcher callback #3
      • NEW: modulus operator #1
    • 1.1.2
      • FIXED: 1.2%1.01 expression would incorrectly match 1.1.01
    • 1.2.0
      • NEW: greater than and less than operators
    • 2.0.0
      • NEW: completely refactored to improve performance
        • Single expression: 23ms to 1ms (23x)
        • Repeated single expression: 77ms to 1ms (77x)
        • Large expression: 4,659ms to 3ms (1,553x)
      • CHANGED: Removed expr.addMatcher in favor of options.expander fn for custom expander logic
    • 2.1.0
      • CHANGED: use meemo for memoization with less allocation and memory churn
    • 2.1.1
      • CHANGED: Use meemo 1.1
    • 2.1.2
      • CHANGED: Use meemoi 1.1.1, fixes issue with referencing window
    • 2.1.3
      • CHANGED: Use meemoi 1.1.2, fixes issue with deoptimized memoization handler

    License

    MIT © Adam Renklint

    Install

    npm i dilla-expressions

    DownloadsWeekly Downloads

    1

    Version

    2.1.3

    License

    MIT

    Last publish

    Collaborators

    • adamrenklint