mathjs/test/expression/node/AccessorNode.test.js

// test AccessorNode
var assert = require('assert');
var approx = require('../../../tools/approx');
var math = require('../../../index');
var bigmath = require('../../../index').create({number: 'BigNumber'});
var Node = math.expression.node.Node;
var ConstantNode = math.expression.node.ConstantNode;
var OperatorNode = math.expression.node.OperatorNode;
var SymbolNode = math.expression.node.SymbolNode;
var AccessorNode = math.expression.node.AccessorNode;
var IndexNode = math.expression.node.IndexNode;
var RangeNode = math.expression.node.RangeNode;

describe('AccessorNode', function() {

  it ('should create a AccessorNode', function () {
    var n = new AccessorNode(new Node(), new IndexNode([]));
    assert(n instanceof AccessorNode);
    assert(n instanceof Node);
    assert.equal(n.type, 'AccessorNode');
  });

  it ('should have isAccessorNode', function () {
    var node = new AccessorNode(new Node(), new IndexNode([]));
    assert(node.isAccessorNode);
  });

  it ('should throw an error when calling with wrong arguments', function () {
    assert.throws(function () {new AccessorNode()}, TypeError);
    assert.throws(function () {new AccessorNode('a', new IndexNode([]))}, TypeError);
    assert.throws(function () {new AccessorNode(new Node, new IndexNode([2, 3]))}, TypeError);
    assert.throws(function () {new AccessorNode(new Node, new IndexNode([new Node(), 3]))}, TypeError);
  });

  it ('should throw an error when calling without new operator', function () {
    assert.throws(function () {AccessorNode(new Node(), new IndexNode([]))}, SyntaxError);
  });

  it ('should get the name of an AccessorNode', function () {
    var n = new AccessorNode(new SymbolNode('a'), new IndexNode([new ConstantNode('toString')]));
    assert.equal(n.name, 'toString');

    var n = new AccessorNode(new SymbolNode('a'), new IndexNode([new ConstantNode(1)]));
    assert.equal(n.name, '');
  });

  it ('should compile a AccessorNode', function () {
    var a = new bigmath.expression.node.SymbolNode('a');
    var index = new IndexNode([
      new bigmath.expression.node.ConstantNode(2),
      new bigmath.expression.node.ConstantNode(1)
    ]);
    var n = new bigmath.expression.node.AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: [[1, 2], [3, 4]]
    };
    assert.equal(expr.eval(scope), 3);
  });

  it ('should compile a AccessorNode with range and context parameters', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([
      new ConstantNode(2),
      new RangeNode(
          new ConstantNode(1),
          new SymbolNode('end')
      )
    ]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: [[1, 2], [3, 4]]
    };
    assert.deepEqual(expr.eval(scope), [[3, 4]]);
  });

  it ('should compile a AccessorNode with a property', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([new ConstantNode('b')]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: { b: 42 }
    };
    assert.deepEqual(expr.eval(scope), 42);
  });

  it ('should throw a one-based index error when out of range (Array)', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([new ConstantNode(4)]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: [1,2,3]
    };
    assert.throws(function () { expr.eval(scope) }, /Index out of range \(4 > 3\)/);
  });

  it ('should throw a one-based index error when out of range (Matrix)', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([new ConstantNode(4)]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: math.matrix([1,2,3])
    };
    assert.throws(function () { expr.eval(scope) }, /Index out of range \(4 > 3\)/);
  });

  it ('should throw a one-based index error when out of range (string)', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([new ConstantNode(4)]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: 'hey'
    };
    assert.throws(function () { expr.eval(scope) }, /Index out of range \(4 > 3\)/);
  });

  it ('should throw an error when applying a matrix index onto an object', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([new ConstantNode(4)]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: {}
    };
    assert.throws(function () { expr.eval(scope) }, /Cannot apply a numeric index as object property/);
  });

  it ('should throw an error when applying an index onto a scalar', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([new ConstantNode(4)]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: 42
    };
    assert.throws(function () { expr.eval(scope) }, /Cannot apply index: unsupported type of object/);
  });

  it ('should compile a AccessorNode with negative step range and context parameters', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([
      new ConstantNode(2),
      new RangeNode(
          new SymbolNode('end'),
          new ConstantNode(1),
          new ConstantNode(-1)
      )
    ]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: [[1, 2], [3, 4]]
    };
    assert.deepEqual(expr.eval(scope), [[4, 3]]);
  });

  it ('should compile a AccessorNode with "end" both as value and in a range', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([
      new SymbolNode('end'),
      new RangeNode(
          new ConstantNode(1),
          new SymbolNode('end')
      )
    ]);
    var n = new AccessorNode(a, index);
    var expr = n.compile();

    var scope = {
      a: [[1, 2], [3, 4]]
    };
    assert.deepEqual(expr.eval(scope), [[3, 4]]);
  });

  it ('should compile a AccessorNode with bignumber setting', function () {
    var a = new bigmath.expression.node.SymbolNode('a');
    var b = new bigmath.expression.node.ConstantNode(2);
    var c = new bigmath.expression.node.ConstantNode(1);
    var n = new bigmath.expression.node.AccessorNode(a, new IndexNode([b, c]));
    var expr = n.compile();

    var scope = {
      a: [[1, 2], [3, 4]]
    };
    assert.deepEqual(expr.eval(scope), 3);
  });

  it ('should filter an AccessorNode', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var index = new IndexNode([b, c]);
    var n = new AccessorNode(a, index);

    assert.deepEqual(n.filter(function (node) {return node.isAccessorNode}),  [n]);
    assert.deepEqual(n.filter(function (node) {return node.isSymbolNode}),    [a]);
    assert.deepEqual(n.filter(function (node) {return node.isRangeNode}),     []);
    assert.deepEqual(n.filter(function (node) {return node.isConstantNode}),  [b, c]);
    assert.deepEqual(n.filter(function (node) {return node.isConstantNode && node.value == '2'}),  [b]);
    assert.deepEqual(n.filter(function (node) {return node.isConstantNode && node.value == '4'}),  []);
  });

  it ('should filter an empty AccessorNode', function () {
    var n = new AccessorNode(new SymbolNode('a'), new IndexNode([]));

    assert.deepEqual(n.filter(function (node) {return node.isAccessorNode}),  [n]);
    assert.deepEqual(n.filter(function (node) {return node.isConstantNode}), []);
  });

  it ('should run forEach on an AccessorNode', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var index = new IndexNode([b, c]);
    var n = new AccessorNode(a, index);

    var nodes = [];
    var paths = [];
    n.forEach(function (node, path, parent) {
      nodes.push(node);
      paths.push(path);
      assert.strictEqual(parent, n);
    });

    assert.equal(nodes.length, 2);
    assert.strictEqual(nodes[0], a);
    assert.strictEqual(nodes[1], index);
    assert.deepEqual(paths, ['object', 'index']);
  });

  it ('should map an AccessorNode', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var index = new IndexNode([b, c]);
    var n = new AccessorNode(a, index);

    var nodes = [];
    var paths = [];
    var e = new SymbolNode('c');
    var f = n.map(function (node, path, parent) {
      nodes.push(node);
      paths.push(path);
      assert.strictEqual(parent, n);

      return node instanceof SymbolNode ? e : node;
    });

    assert.equal(nodes.length, 2);
    assert.strictEqual(nodes[0], a);
    assert.strictEqual(nodes[1], index);
    assert.deepEqual(paths, ['object', 'index']);

    assert.notStrictEqual(f, n);
    assert.deepEqual(f.object, e);
    assert.deepEqual(f.index.dimensions[0], b);
    assert.deepEqual(f.index.dimensions[1], c);
  });

  it ('should throw an error when the map callback does not return a node', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var n = new AccessorNode(a, new IndexNode([b, c]));

    assert.throws(function () {
      n.map(function () {});
    }, /Callback function must return a Node/)
  });

  it ('should transform an IndexNodes object', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var n = new AccessorNode(a, new IndexNode([b, c]));

    var e = new SymbolNode('c');
    var f = n.transform(function (node) {
      return node instanceof SymbolNode ? e : node;
    });

    assert.notStrictEqual(f, n);
    assert.deepEqual(f.object, e);
    assert.deepEqual(f.index.dimensions[0], b);
    assert.deepEqual(f.index.dimensions[1], c);
  });

  it ('should transform an IndexNodes (nested) parameters', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var n = new AccessorNode(a, new IndexNode([b, c]));

    var e = new SymbolNode('c');
    var f = n.transform(function (node) {
      return node instanceof ConstantNode && node.value == '1' ? e : node;
    });

    assert.notStrictEqual(f, n);
    assert.deepEqual(f.object, a);
    assert.deepEqual(f.index.dimensions[0], b);
    assert.deepEqual(f.index.dimensions[1], e);
  });

  it ('should transform an AccessorNode itself', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var n = new AccessorNode(a, new IndexNode([b, c]));

    var e = new ConstantNode(5);
    var f = n.transform(function (node) {
      return node instanceof AccessorNode ? e : node;
    });

    assert.notStrictEqual(f, n);
    assert.deepEqual(f, e);
  });

  it ('should clone an AccessorNode', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var n = new AccessorNode(a, new IndexNode([b, c]));

    var d = n.clone();
    assert(d instanceof AccessorNode);
    assert.deepEqual(d, n);
    assert.notStrictEqual(d, n);
    assert.strictEqual(d.object, n.object);
    assert.strictEqual(d.index, n.index);
    assert.strictEqual(d.index.dimensions[0], n.index.dimensions[0]);
    assert.strictEqual(d.index.dimensions[1], n.index.dimensions[1]);
  });

  it ('should test equality of an Node', function () {
    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var node1 = new AccessorNode(a, new IndexNode([b, c]));

    var a = new SymbolNode('a');
    var b = new SymbolNode('b');
    var c = new ConstantNode(1);
    var node2 = new AccessorNode(a, new IndexNode([b, c]));

    var a = new SymbolNode('a');
    var b = new ConstantNode(2);
    var c = new ConstantNode(1);
    var node3 = new AccessorNode(a, new IndexNode([b, c]));

    assert.strictEqual(node1.equals(null), false);
    assert.strictEqual(node1.equals(undefined), false);
    assert.strictEqual(node1.equals(node2), false);
    assert.strictEqual(node1.equals(node3), true);
  });

  it ('should stringify an AccessorNode', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([
      new ConstantNode(2),
      new ConstantNode(1)
    ]);

    var n = new AccessorNode(a, index);
    assert.equal(n.toString(), 'a[2, 1]');

    var n2 = new AccessorNode(a, new IndexNode([]));
    assert.equal(n2.toString(), 'a[]')
  });

  it ('should stringify an AccessorNode with parentheses', function () {
    var a = new SymbolNode('a');
    var b = new SymbolNode('b');
    var add = new OperatorNode('+', 'add', [a, b]);
    var bar = new AccessorNode(add, new IndexNode([new ConstantNode('bar')]));
    assert.equal(bar.toString(), '(a + b)["bar"]');
  });

  it ('should stringify nested AccessorNode', function () {
    var a = new SymbolNode('a');
    var foo = new AccessorNode(a, new IndexNode([new ConstantNode('foo')]));
    var bar = new AccessorNode(foo, new IndexNode([new ConstantNode('bar')]));
    assert.equal(bar.toString(), 'a["foo"]["bar"]');
  });

  it ('should stringigy an AccessorNode with custom toString', function () {
    //Also checks if the custom functions get passed on to the children
    var customFunction = function (node, options) {
      if (node.type === 'AccessorNode') {
        var string = node.object.toString(options) + ' at ';
        node.index.dimensions.forEach(function (range) {
          string += range.toString(options) + ', ';
        });

        return string;
      }
      else if (node.type === 'ConstantNode') {
        return 'const(' + node.value + ', ' + node.valueType + ')'
      }
    };

    var a = new SymbolNode('a');
    var b = new ConstantNode(1);
    var c = new ConstantNode(2);

    var n = new AccessorNode(a, new IndexNode([b, c]));

    assert.equal(n.toString({handler: customFunction}), 'a at const(1, number), const(2, number), ');
  });

  it ('should LaTeX an AccessorNode', function () {
    var a = new SymbolNode('a');
    var index = new IndexNode([
      new ConstantNode(2),
      new ConstantNode(1)
    ]);

    var n = new AccessorNode(a, index);
    assert.equal(n.toTex(), ' a_{2,1}');

    var n2 = new AccessorNode(a, new IndexNode([]));
    assert.equal(n2.toTex(), ' a_{}')
  });

  it ('should LaTeX an AccessorNode with custom toTex', function () {
    //Also checks if the custom functions get passed on to the children
    var customFunction = function (node, options) {
      if (node.type === 'AccessorNode') {
        var latex = node.object.toTex(options) + ' at ';
        node.index.dimensions.forEach(function (range) {
          latex += range.toTex(options) + ', ';
        });

        return latex;
      }
      else if (node.type === 'ConstantNode') {
        return 'const\\left(' + node.value + ', ' + node.valueType + '\\right)'
      }
    };

    var a = new SymbolNode('a');
    var b = new ConstantNode(1);
    var c = new ConstantNode(2);

    var n = new AccessorNode(a, new IndexNode([b, c]));

    assert.equal(n.toTex({handler: customFunction}), ' a at const\\left(1, number\\right), const\\left(2, number\\right), ');
  });

});