151 lines
4.4 KiB
JavaScript
151 lines
4.4 KiB
JavaScript
import { factory } from '../utils/factory.js';
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import { createEmptyMap, toObject } from '../utils/map.js';
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var name = 'Parser';
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var dependencies = ['evaluate'];
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export var createParserClass = /* #__PURE__ */factory(name, dependencies, _ref => {
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var {
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evaluate
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} = _ref;
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/**
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* @constructor Parser
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* Parser contains methods to evaluate or parse expressions, and has a number
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* of convenience methods to get, set, and remove variables from memory. Parser
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* keeps a scope containing variables in memory, which is used for all
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* evaluations.
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*
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* Methods:
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* const result = parser.evaluate(expr) // evaluate an expression
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* const value = parser.get(name) // retrieve a variable from the parser
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* const values = parser.getAll() // retrieve all defined variables
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* parser.set(name, value) // set a variable in the parser
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* parser.remove(name) // clear a variable from the
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* // parsers scope
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* parser.clear() // clear the parsers scope
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*
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* Example usage:
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* const parser = new Parser()
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* // Note: there is a convenience method which can be used instead:
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* // const parser = new math.parser()
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*
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* // evaluate expressions
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* parser.evaluate('sqrt(3^2 + 4^2)') // 5
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* parser.evaluate('sqrt(-4)') // 2i
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* parser.evaluate('2 inch in cm') // 5.08 cm
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* parser.evaluate('cos(45 deg)') // 0.7071067811865476
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*
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* // define variables and functions
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* parser.evaluate('x = 7 / 2') // 3.5
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* parser.evaluate('x + 3') // 6.5
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* parser.evaluate('f(x, y) = x^y') // f(x, y)
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* parser.evaluate('f(2, 3)') // 8
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*
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* // get and set variables and functions
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* const x = parser.get('x') // 7
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* const f = parser.get('f') // function
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* const g = f(3, 2) // 9
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* parser.set('h', 500)
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* const i = parser.evaluate('h / 2') // 250
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* parser.set('hello', function (name) {
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* return 'hello, ' + name + '!'
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* })
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* parser.evaluate('hello("user")') // "hello, user!"
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*
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* // clear defined functions and variables
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* parser.clear()
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*
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*/
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function Parser() {
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if (!(this instanceof Parser)) {
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throw new SyntaxError('Constructor must be called with the new operator');
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}
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Object.defineProperty(this, 'scope', {
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value: createEmptyMap(),
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writable: false
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});
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}
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/**
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* Attach type information
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*/
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Parser.prototype.type = 'Parser';
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Parser.prototype.isParser = true;
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/**
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* Parse and evaluate the given expression
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* @param {string | string[]} expr A string containing an expression,
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* for example "2+3", or a list with expressions
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* @return {*} result The result, or undefined when the expression was empty
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* @throws {Error}
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*/
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Parser.prototype.evaluate = function (expr) {
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// TODO: validate arguments
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return evaluate(expr, this.scope);
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};
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/**
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* Get a variable (a function or variable) by name from the parsers scope.
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* Returns undefined when not found
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* @param {string} name
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* @return {* | undefined} value
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*/
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Parser.prototype.get = function (name) {
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// TODO: validate arguments
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if (this.scope.has(name)) {
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return this.scope.get(name);
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}
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};
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/**
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* Get a map with all defined variables
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* @return {Object} values
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*/
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Parser.prototype.getAll = function () {
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return toObject(this.scope);
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};
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/**
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* Get a map with all defined variables
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* @return {Map} values
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*/
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Parser.prototype.getAllAsMap = function () {
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return this.scope;
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};
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/**
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* Set a symbol (a function or variable) by name from the parsers scope.
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* @param {string} name
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* @param {* | undefined} value
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*/
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Parser.prototype.set = function (name, value) {
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this.scope.set(name, value);
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return value;
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};
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/**
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* Remove a variable from the parsers scope
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* @param {string} name
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*/
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Parser.prototype.remove = function (name) {
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this.scope.delete(name);
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};
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/**
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* Clear the scope with variables and functions
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*/
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Parser.prototype.clear = function () {
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this.scope.clear();
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};
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return Parser;
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}, {
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isClass: true
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}); |