mathjs
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Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif
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JavaScript
'use strict';
var map = require('../../utils/array').map;
var escape = require('../../utils/string').escape;
function factory(type, config, load, typed) {
var Node = load(require('./Node'));
var Range = load(require('../../type/matrix/Range'));
var isArray = Array.isArray;
/**
* @constructor IndexNode
* @extends Node
*
* Describes a subset of a matrix or an object property.
* Cannot be used on its own, needs to be used within an AccessorNode or
* AssignmentNode.
*
* @param {Node[]} dimensions
* @param {boolean} [dotNotation=false] Optional property describing whether
* this index was written using dot
* notation like `a.b`, or using bracket
* notation like `a["b"]` (default).
* Used to stringify an IndexNode.
*/
function IndexNode(dimensions, dotNotation) {
if (!(this instanceof IndexNode)) {
throw new SyntaxError('Constructor must be called with the new operator');
}
this.dimensions = dimensions;
this.dotNotation = dotNotation || false; // validate input
if (!isArray(dimensions) || !dimensions.every(type.isNode)) {
throw new TypeError('Array containing Nodes expected for parameter "dimensions"');
}
if (this.dotNotation && !this.isObjectProperty()) {
throw new Error('dotNotation only applicable for object properties');
} // TODO: deprecated since v3, remove some day
var deprecated = function deprecated() {
throw new Error('Property `IndexNode.object` is deprecated, use `IndexNode.fn` instead');
};
Object.defineProperty(this, 'object', {
get: deprecated,
set: deprecated
});
}
IndexNode.prototype = new Node();
IndexNode.prototype.type = 'IndexNode';
IndexNode.prototype.isIndexNode = true;
/**
* Compile a node into a JavaScript function.
* This basically pre-calculates as much as possible and only leaves open
* calculations which depend on a dynamic scope with variables.
* @param {Object} math Math.js namespace with functions and constants.
* @param {Object} argNames An object with argument names as key and `true`
* as value. Used in the SymbolNode to optimize
* for arguments from user assigned functions
* (see FunctionAssignmentNode) or special symbols
* like `end` (see IndexNode).
* @return {function} Returns a function which can be called like:
* evalNode(scope: Object, args: Object, context: *)
*/
IndexNode.prototype._compile = function (math, argNames) {
// TODO: implement support for bignumber (currently bignumbers are silently
// reduced to numbers when changing the value to zero-based)
// TODO: Optimization: when the range values are ConstantNodes,
// we can beforehand resolve the zero-based value
// optimization for a simple object property
var evalDimensions = map(this.dimensions, function (range, i) {
if (type.isRangeNode(range)) {
if (range.needsEnd()) {
// create a range containing end (like '4:end')
var childArgNames = Object.create(argNames);
childArgNames['end'] = true;
var evalStart = range.start._compile(math, childArgNames);
var evalEnd = range.end._compile(math, childArgNames);
var evalStep = range.step ? range.step._compile(math, childArgNames) : function () {
return 1;
};
return function evalDimension(scope, args, context) {
var size = math.size(context).valueOf();
var childArgs = Object.create(args);
childArgs['end'] = size[i];
return createRange(evalStart(scope, childArgs, context), evalEnd(scope, childArgs, context), evalStep(scope, childArgs, context));
};
} else {
// create range
var _evalStart = range.start._compile(math, argNames);
var _evalEnd = range.end._compile(math, argNames);
var _evalStep = range.step ? range.step._compile(math, argNames) : function () {
return 1;
};
return function evalDimension(scope, args, context) {
return createRange(_evalStart(scope, args, context), _evalEnd(scope, args, context), _evalStep(scope, args, context));
};
}
} else if (type.isSymbolNode(range) && range.name === 'end') {
// SymbolNode 'end'
var _childArgNames = Object.create(argNames);
_childArgNames['end'] = true;
var evalRange = range._compile(math, _childArgNames);
return function evalDimension(scope, args, context) {
var size = math.size(context).valueOf();
var childArgs = Object.create(args);
childArgs['end'] = size[i];
return evalRange(scope, childArgs, context);
};
} else {
// ConstantNode
var _evalRange = range._compile(math, argNames);
return function evalDimension(scope, args, context) {
return _evalRange(scope, args, context);
};
}
});
return function evalIndexNode(scope, args, context) {
var dimensions = map(evalDimensions, function (evalDimension) {
return evalDimension(scope, args, context);
});
return math.index.apply(math, dimensions);
};
};
/**
* Execute a callback for each of the child nodes of this node
* @param {function(child: Node, path: string, parent: Node)} callback
*/
IndexNode.prototype.forEach = function (callback) {
for (var i = 0; i < this.dimensions.length; i++) {
callback(this.dimensions[i], 'dimensions[' + i + ']', this);
}
};
/**
* Create a new IndexNode having it's childs be the results of calling
* the provided callback function for each of the childs of the original node.
* @param {function(child: Node, path: string, parent: Node): Node} callback
* @returns {IndexNode} Returns a transformed copy of the node
*/
IndexNode.prototype.map = function (callback) {
var dimensions = [];
for (var i = 0; i < this.dimensions.length; i++) {
dimensions[i] = this._ifNode(callback(this.dimensions[i], 'dimensions[' + i + ']', this));
}
return new IndexNode(dimensions);
};
/**
* Create a clone of this node, a shallow copy
* @return {IndexNode}
*/
IndexNode.prototype.clone = function () {
return new IndexNode(this.dimensions.slice(0));
};
/**
* Test whether this IndexNode contains a single property name
* @return {boolean}
*/
IndexNode.prototype.isObjectProperty = function () {
return this.dimensions.length === 1 && type.isConstantNode(this.dimensions[0]) && typeof this.dimensions[0].value === 'string';
};
/**
* Returns the property name if IndexNode contains a property.
* If not, returns null.
* @return {string | null}
*/
IndexNode.prototype.getObjectProperty = function () {
return this.isObjectProperty() ? this.dimensions[0].value : null;
};
/**
* Get string representation
* @param {Object} options
* @return {string} str
*/
IndexNode.prototype._toString = function (options) {
// format the parameters like "[1, 0:5]"
return this.dotNotation ? '.' + this.getObjectProperty() : '[' + this.dimensions.join(', ') + ']';
};
/**
* Get a JSON representation of the node
* @returns {Object}
*/
IndexNode.prototype.toJSON = function () {
return {
mathjs: 'IndexNode',
dimensions: this.dimensions,
dotNotation: this.dotNotation
};
};
/**
* Instantiate an IndexNode from its JSON representation
* @param {Object} json An object structured like
* `{"mathjs": "IndexNode", dimensions: [...], dotNotation: false}`,
* where mathjs is optional
* @returns {IndexNode}
*/
IndexNode.fromJSON = function (json) {
return new IndexNode(json.dimensions, json.dotNotation);
};
/**
* Get HTML representation
* @param {Object} options
* @return {string} str
*/
IndexNode.prototype.toHTML = function (options) {
// format the parameters like "[1, 0:5]"
var dimensions = [];
for (var i = 0; i < this.dimensions.length; i++) {
dimensions[i] = this.dimensions[i].toHTML();
}
if (this.dotNotation) {
return '<span class="math-operator math-accessor-operator">.</span>' + '<span class="math-symbol math-property">' + escape(this.getObjectProperty()) + '</span>';
} else {
return '<span class="math-parenthesis math-square-parenthesis">[</span>' + dimensions.join('<span class="math-separator">,</span>') + '<span class="math-parenthesis math-square-parenthesis">]</span>';
}
};
/**
* Get LaTeX representation
* @param {Object} options
* @return {string} str
*/
IndexNode.prototype._toTex = function (options) {
var dimensions = this.dimensions.map(function (range) {
return range.toTex(options);
});
return this.dotNotation ? '.' + this.getObjectProperty() + '' : '_{' + dimensions.join(',') + '}';
}; // helper function to create a Range from start, step and end
function createRange(start, end, step) {
return new Range(type.isBigNumber(start) ? start.toNumber() : start, type.isBigNumber(end) ? end.toNumber() : end, type.isBigNumber(step) ? step.toNumber() : step);
}
return IndexNode;
}
exports.name = 'IndexNode';
exports.path = 'expression.node';
exports.factory = factory;