From 3a81441d0bc37dfb7a1c8aeefba8b523885e2c1e Mon Sep 17 00:00:00 2001 From: Ad5001 Date: Sun, 13 Oct 2024 00:33:22 +0200 Subject: [PATCH] Finished expr-eval testing --- common/src/lib/expr-eval/expression.mjs | 14 +- common/src/lib/expr-eval/parser.mjs | 11 +- common/src/lib/expr-eval/polyfill.mjs | 55 +---- common/src/module/expreval.mjs | 4 +- common/test/module/expreval.mjs | 308 ++++++++++++++++++++---- 5 files changed, 260 insertions(+), 132 deletions(-) diff --git a/common/src/lib/expr-eval/expression.mjs b/common/src/lib/expr-eval/expression.mjs index d89d67e..f782fa3 100644 --- a/common/src/lib/expr-eval/expression.mjs +++ b/common/src/lib/expr-eval/expression.mjs @@ -111,7 +111,7 @@ function simplify(tokens, unaryOps, binaryOps, ternaryOps, values) { * In the given instructions, replaces variable by expr. * @param {Instruction[]} tokens * @param {string} variable - * @param {number} expr + * @param {ExprEvalExpression} expr * @return {Instruction[]} */ function substitute(tokens, variable, expr) { @@ -487,18 +487,6 @@ export class ExprEvalExpression { return evaluate(this.tokens, this, values) } - /** - * Returns a list of symbols (string of characters) in the expressions. - * Can be functions, constants, or variables. - * @returns {string[]} - */ - symbols(options) { - options = options || {} - const vars = [] - getSymbols(this.tokens, vars, options) - return vars - } - toString() { return expressionToString(this.tokens, false) } diff --git a/common/src/lib/expr-eval/parser.mjs b/common/src/lib/expr-eval/parser.mjs index ba920c6..e27d512 100644 --- a/common/src/lib/expr-eval/parser.mjs +++ b/common/src/lib/expr-eval/parser.mjs @@ -120,18 +120,13 @@ export class Parser { min: Polyfill.min, max: Polyfill.max, hypot: Math.hypot || Polyfill.hypot, - pyt: Math.hypot || Polyfill.hypot, // backward compat + pyt: Math.hypot || Polyfill.hypot, pow: Math.pow, atan2: Math.atan2, "if": Polyfill.condition, gamma: Polyfill.gamma, "Γ": Polyfill.gamma, roundTo: Polyfill.roundTo, - map: Polyfill.arrayMap, - fold: Polyfill.arrayFold, - filter: Polyfill.arrayFilter, - indexOf: Polyfill.stringOrArrayIndexOf, - join: Polyfill.arrayJoin } // These constants will automatically be replaced the MOMENT they are parsed. @@ -156,10 +151,6 @@ export class Parser { return new ExprEvalExpression(instr, this) } - evaluate(expr, variables) { - return this.parse(expr).evaluate(variables) - } - isOperatorEnabled(op) { const optionName = optionNameMap.hasOwnProperty(op) ? optionNameMap[op] : op const operators = this.options.operators || {} diff --git a/common/src/lib/expr-eval/polyfill.mjs b/common/src/lib/expr-eval/polyfill.mjs index 9e8e885..c618aaf 100644 --- a/common/src/lib/expr-eval/polyfill.mjs +++ b/common/src/lib/expr-eval/polyfill.mjs @@ -210,9 +210,8 @@ export function gamma(n) { } export function stringOrArrayLength(s) { - if(Array.isArray(s)) { + if(Array.isArray(s)) return s.length - } return String(s).length } @@ -296,58 +295,6 @@ export function min(array) { } } -export function arrayMap(f, a) { - if(typeof f !== "function") { - throw new EvalError(qsTranslate("error", "First argument to map is not a function.")) - } - if(!Array.isArray(a)) { - throw new EvalError(qsTranslate("error", "Second argument to map is not an array.")) - } - return a.map(function(x, i) { - return f(x, i) - }) -} - -export function arrayFold(f, init, a) { - if(typeof f !== "function") { - throw new EvalError(qsTranslate("error", "First argument to fold is not a function.")) - } - if(!Array.isArray(a)) { - throw new EvalError(qsTranslate("error", "Second argument to fold is not an array.")) - } - return a.reduce(function(acc, x, i) { - return f(acc, x, i) - }, init) -} - -export function arrayFilter(f, a) { - if(typeof f !== "function") { - throw new EvalError(qsTranslate("error", "First argument to filter is not a function.")) - } - if(!Array.isArray(a)) { - throw new EvalError(qsTranslate("error", "Second argument to filter is not an array.")) - } - return a.filter(function(x, i) { - return f(x, i) - }) -} - -export function stringOrArrayIndexOf(target, s) { - if(!(Array.isArray(s) || typeof s === "string")) { - throw new Error(qsTranslate("error", "Second argument to indexOf is not a string or array.")) - } - - return s.indexOf(target) -} - -export function arrayJoin(sep, a) { - if(!Array.isArray(a)) { - throw new Error(qsTranslate("error", "Second argument to join is not an array.")) - } - - return a.join(sep) -} - export function sign(x) { return ((x > 0) - (x < 0)) || +x } diff --git a/common/src/module/expreval.mjs b/common/src/module/expreval.mjs index 7b40b2f..8440282 100644 --- a/common/src/module/expreval.mjs +++ b/common/src/module/expreval.mjs @@ -19,7 +19,7 @@ import { Module } from "./common.mjs" import { Parser } from "../lib/expr-eval/parser.mjs" -const evalVariables = { +const EVAL_VARIABLES = { // Variables not provided by expr-eval.js, needs to be provided manually "pi": Math.PI, "PI": Math.PI, @@ -42,7 +42,7 @@ class ExprParserAPI extends Module { this.currentVars = {} this.#parser = new Parser() - this.#parser.consts = Object.assign({}, this.#parser.consts, evalVariables) + this.#parser.consts = Object.assign({}, this.#parser.consts, EVAL_VARIABLES) this.#parser.functions.integral = this.integral.bind(this) this.#parser.functions.derivative = this.derivative.bind(this) diff --git a/common/test/module/expreval.mjs b/common/test/module/expreval.mjs index c9361f0..2d075f6 100644 --- a/common/test/module/expreval.mjs +++ b/common/test/module/expreval.mjs @@ -25,72 +25,274 @@ import { expect } from "chai" import ExprEval from "../../src/module/expreval.mjs" describe("Module/ExprEval", function() { - describe("#parse", function() { - const evaluate = (expr, vals) => ExprEval.parse(expr).evaluate(vals) + describe("#parse.evaluate", function() { + const evaluate = (expr, vals = {}) => ExprEval.parse(expr).evaluate(vals) it("parses simple mathematical expressions", function() { - expect(evaluate("1", {})).to.equal(1) - expect(evaluate("-1", {})).to.equal(-1) - expect(evaluate("-(-1)", {})).to.equal(1) - expect(evaluate("+(-1)", {})).to.equal(-1) - expect(evaluate("3!", {})).to.equal(6) - expect(evaluate("1+1", {})).to.equal(2) - expect(evaluate("4*3", {})).to.equal(12) - expect(evaluate("64/4", {})).to.equal(16) - expect(evaluate("2^10", {})).to.equal(1024) - expect(evaluate("10%3", {})).to.equal(1) - expect(evaluate("10%3", {})).to.equal(1) + expect(evaluate(`"\\'\\"\\\\\\/\\b\\f\\n\\r\\t\\u3509"`)).to.equal(`'"\\/\b\f\n\r\t\u3509`) + expect(evaluate("1")).to.equal(1) + expect(evaluate(" 1 ")).to.equal(1) + expect(evaluate("0xFF")).to.equal(255) + expect(evaluate("0b11")).to.equal(3) + expect(evaluate("-1")).to.equal(-1) + expect(evaluate("-(-1)")).to.equal(1) + expect(evaluate("+(-1)")).to.equal(-1) + expect(evaluate("3!")).to.equal(6) + expect(evaluate("1+1")).to.equal(2) + expect(evaluate("4*3")).to.equal(12) + expect(evaluate("4•3")).to.equal(12) + expect(evaluate("64/4")).to.equal(16) + expect(evaluate("2^10")).to.equal(1024) + expect(evaluate("10%3")).to.equal(1) + expect(evaluate("10%3")).to.equal(1) // Test priorities - expect(evaluate("10*10+10*10", {})).to.equal(200) - expect(evaluate("10/10+10/10", {})).to.equal(2) - expect(evaluate("10/10+10/10", {})).to.equal(2) - expect(evaluate("2^2-2^2", {})).to.equal(0) - expect(evaluate("(2^2-2)^2", {})).to.equal(4) + expect(evaluate("10*10+10*10")).to.equal(200) + expect(evaluate("10/10+10/10")).to.equal(2) + expect(evaluate("10/10+10/10")).to.equal(2) + expect(evaluate("2^2-2^2")).to.equal(0) + expect(evaluate("(2^2-2)^2")).to.equal(4) }) it("parses equality and test statements", function() { - expect(evaluate("10%3 == 1 ? 2 : 1", {})).to.equal(2) - expect(evaluate("10%3 != 1 ? 2 : 1", {})).to.equal(1) - expect(evaluate("10 < 3 ? 2 : 1", {})).to.equal(1) - expect(evaluate("10 > 3 ? (2+1) : 1", {})).to.equal(3) - expect(evaluate("10 <= 3 ? 4 : 1", {})).to.equal(1) - expect(evaluate("10 >= 3 ? 4 : 1", {})).to.equal(4) + expect(evaluate("10%3 == 1 ? 2 : 1")).to.equal(2) + expect(evaluate("not(10%3 == 1) ? 2 : 1")).to.equal(1) + expect(evaluate("10%3 != 1 ? 2 : 1")).to.equal(1) + expect(evaluate("10 < 3 ? 2 : 1")).to.equal(1) + expect(evaluate("10 > 3 ? (2+1) : 1")).to.equal(3) + expect(evaluate("10 <= 3 ? 4 : 1")).to.equal(1) + expect(evaluate("10 >= 3 ? 4 : 1")).to.equal(4) // Check equality - expect(evaluate("10 < 10 ? 2 : 1", {})).to.equal(1) - expect(evaluate("10 > 10 ? 2 : 1", {})).to.equal(1) - expect(evaluate("10 <= 10 ? 4 : 1", {})).to.equal(4) - expect(evaluate("10 >= 10 ? 4 : 1", {})).to.equal(4) + expect(evaluate("10 < 10 ? 2 : 1")).to.equal(1) + expect(evaluate("10 > 10 ? 2 : 1")).to.equal(1) + expect(evaluate("10 <= 10 ? 4 : 1")).to.equal(4) + expect(evaluate("10 >= 10 ? 4 : 1")).to.equal(4) // Check 'and' and 'or' - expect(evaluate("10 <= 3 and 10 < 10 ? 4 : 1", {})).to.equal(1) - expect(evaluate("10 <= 10 and 10 < 10 ? 4 : 1", {})).to.equal(1) - expect(evaluate("10 <= 10 and 10 < 20 ? 4 : 1", {})).to.equal(4) - expect(evaluate("10 <= 3 or 10 < 10 ? 4 : 1", {})).to.equal(1) - expect(evaluate("10 <= 10 or 10 < 10 ? 4 : 1", {})).to.equal(4) - expect(evaluate("10 <= 10 or 10 < 20 ? 4 : 1", {})).to.equal(4) + expect(evaluate("10 <= 3 and 10 < 10 ? 4 : 1")).to.equal(1) + expect(evaluate("10 <= 10 and 10 < 10 ? 4 : 1")).to.equal(1) + expect(evaluate("10 <= 10 and 10 < 20 ? 4 : 1")).to.equal(4) + expect(evaluate("10 <= 3 or 10 < 10 ? 4 : 1")).to.equal(1) + expect(evaluate("10 <= 10 or 10 < 10 ? 4 : 1")).to.equal(4) + expect(evaluate("10 <= 10 or 10 < 20 ? 4 : 1")).to.equal(4) }) it("parses singular function operators (functions with one arguments and no parenthesis)", function() { // Trigonometric functions - expect(evaluate("sin π", { })).to.be.approximately(0, Number.EPSILON) - expect(evaluate("cos π", { })).to.be.approximately(-1, Number.EPSILON) - expect(evaluate("tan π", { })).to.be.approximately(0, Number.EPSILON) - expect(evaluate("asin 1", { })).to.be.approximately(Math.PI/2, Number.EPSILON) - expect(evaluate("acos 1", { })).to.be.approximately(0, Number.EPSILON) - expect(evaluate("atan 1", { })).to.be.approximately(Math.PI/4, Number.EPSILON) - expect(evaluate("sinh 1", { })).to.be.approximately(Math.sinh(1), Number.EPSILON) - expect(evaluate("cosh 1", { })).to.be.approximately(Math.cosh(1), Number.EPSILON) - expect(evaluate("tanh 1", { })).to.be.approximately(Math.tanh(1), Number.EPSILON) - expect(evaluate("asinh 1", { })).to.be.approximately(Math.asinh(1), Number.EPSILON) - expect(evaluate("acosh 1", { })).to.be.approximately(Math.acosh(1), Number.EPSILON) - expect(evaluate("atanh 0.5", { })).to.be.approximately(Math.atanh(0.5), Number.EPSILON) + expect(evaluate("sin 0")).to.be.approximately(0, Number.EPSILON) + expect(evaluate("cos 0")).to.be.approximately(1, Number.EPSILON) + expect(evaluate("tan 0")).to.be.approximately(0, Number.EPSILON) + expect(evaluate("asin 1")).to.be.approximately(Math.PI / 2, Number.EPSILON) + expect(evaluate("acos 1")).to.be.approximately(0, Number.EPSILON) + expect(evaluate("atan 1")).to.be.approximately(Math.PI / 4, Number.EPSILON) + expect(evaluate("sinh 1")).to.be.approximately(Math.sinh(1), Number.EPSILON) + expect(evaluate("cosh 1")).to.be.approximately(Math.cosh(1), Number.EPSILON) + expect(evaluate("tanh 1")).to.be.approximately(Math.tanh(1), Number.EPSILON) + expect(evaluate("asinh 1")).to.be.approximately(Math.asinh(1), Number.EPSILON) + expect(evaluate("acosh 1")).to.be.approximately(Math.acosh(1), Number.EPSILON) + expect(evaluate("atanh 0.5")).to.be.approximately(Math.atanh(0.5), Number.EPSILON) // Reverse trigonometric - expect(evaluate("asin sin 1", { })).to.be.approximately(1, Number.EPSILON) - expect(evaluate("acos cos 1", { })).to.be.approximately(1, Number.EPSILON) - expect(evaluate("atan tan 1", { })).to.be.approximately(1, Number.EPSILON) - expect(evaluate("asinh sinh 1", { })).to.be.approximately(1, Number.EPSILON) - expect(evaluate("acosh cosh 1", { })).to.be.approximately(1, Number.EPSILON) - expect(evaluate("atanh tanh 1", { })).to.be.approximately(1, Number.EPSILON) + expect(evaluate("asin sin 1")).to.be.approximately(1, Number.EPSILON) + expect(evaluate("acos cos 1")).to.be.approximately(1, Number.EPSILON) + expect(evaluate("atan tan 1")).to.be.approximately(1, Number.EPSILON) + expect(evaluate("asinh sinh 1")).to.be.approximately(1, Number.EPSILON) + expect(evaluate("acosh cosh 1")).to.be.approximately(1, Number.EPSILON) + expect(evaluate("atanh tanh 1")).to.be.approximately(1, Number.EPSILON) // Other functions + expect(evaluate("sqrt 4")).to.be.approximately(2, Number.EPSILON) + expect(evaluate("sqrt 2")).to.be.approximately(Math.sqrt(2), Number.EPSILON) + expect(evaluate("cbrt 27")).to.be.approximately(3, Number.EPSILON) + expect(evaluate("cbrt 14")).to.be.approximately(Math.cbrt(14), Number.EPSILON) + expect(evaluate("log 1")).to.be.approximately(Math.log(1), Number.EPSILON) + expect(evaluate("ln 1")).to.be.approximately(Math.log(1), Number.EPSILON) + expect(evaluate("log2 8")).to.be.approximately(3, Number.EPSILON) + expect(evaluate("log10 100")).to.be.approximately(2, Number.EPSILON) + expect(evaluate("lg 100")).to.be.approximately(2, Number.EPSILON) + expect(evaluate("expm1 0")).to.be.approximately(0, Number.EPSILON) + expect(evaluate("expm1 10")).to.be.approximately(Math.expm1(10), Number.EPSILON) + expect(evaluate("log1p 0")).to.be.approximately(0, Number.EPSILON) + expect(evaluate("log1p 10")).to.be.approximately(Math.log1p(10), Number.EPSILON) + // Roundings/Sign transformations + expect(evaluate("abs -12.34")).to.equal(12.34) + expect(evaluate("abs 12.45")).to.equal(12.45) + expect(evaluate("ceil 12.45")).to.equal(13) + expect(evaluate("ceil 12.75")).to.equal(13) + expect(evaluate("ceil 12.0")).to.equal(12) + expect(evaluate("ceil -12.6")).to.equal(-12) + expect(evaluate("floor 12.45")).to.equal(12) + expect(evaluate("floor 12.75")).to.equal(12) + expect(evaluate("floor 12.0")).to.equal(12) + expect(evaluate("floor -12.2")).to.equal(-13) + expect(evaluate("round 12.45")).to.equal(12) + expect(evaluate("round 12.75")).to.equal(13) + expect(evaluate("round 12.0")).to.equal(12) + expect(evaluate("round -12.2")).to.equal(-12) + expect(evaluate("round -12.6")).to.equal(-13) + expect(evaluate("trunc 12.45")).to.equal(12) + expect(evaluate("trunc 12.75")).to.equal(12) + expect(evaluate("trunc 12.0")).to.equal(12) + expect(evaluate("trunc -12.2")).to.equal(-12) + expect(evaluate("exp 1")).to.be.approximately(Math.E, Number.EPSILON) + expect(evaluate("exp 10")).to.be.approximately(Math.pow(Math.E, 10), 1e-8) + expect(evaluate("length \"string\"")).to.equal(6) + expect(evaluate("sign 0")).to.equal(0) + expect(evaluate("sign -0")).to.equal(0) + expect(evaluate("sign -10")).to.equal(-1) + expect(evaluate("sign 80")).to.equal(1) }) + + it("parses regular functions", function() { + for(let i = 0; i < 1000; i++) { + expect(evaluate("random()")).to.be.within(0, 1) + expect(evaluate("random(100)")).to.be.within(0, 100) + } + expect(evaluate("fac(3)")).to.equal(6) + expect(evaluate("fac(10)")).to.equal(3628800) + expect(evaluate("min(10, 20)")).to.equal(10) + expect(evaluate("min(-10, -20)")).to.equal(-20) + expect(evaluate("max(10, 20)")).to.equal(20) + expect(evaluate("max(-10, -20)")).to.equal(-10) + expect(evaluate("hypot(3, 4)")).to.equal(5) + expect(evaluate("pyt(30, 40)")).to.equal(50) + expect(evaluate("atan2(1, 1)")).to.be.approximately(Math.PI / 4, Number.EPSILON) + expect(evaluate("atan2(1, 0)")).to.be.approximately(Math.PI / 2, Number.EPSILON) + expect(evaluate("atan2(0, 1)")).to.be.approximately(0, Number.EPSILON) + expect(evaluate("if(10 == 10, 1, 0)")).to.be.approximately(1, Number.EPSILON) + expect(evaluate("if(10 != 10, 1, 0)")).to.be.approximately(0, Number.EPSILON) + expect(evaluate("gamma(10) == 9!")).to.be.true + expect(evaluate("Γ(30) == 29!")).to.be.true + expect(evaluate("Γ(25) == 23!")).to.be.false + expect(evaluate("roundTo(26.04)")).to.equal(26) + expect(evaluate("roundTo(26.04, 2)")).to.equal(26.04) + expect(evaluate("roundTo(26.04836432123, 5)")).to.equal(26.04836) + expect(evaluate("roundTo(26.04836432123, 5)")).to.equal(26.04836) + }) + + it("parses arrays and access their members", function() { + expect(evaluate("[6, 7, 9]")).to.have.lengthOf(3) + expect(evaluate("[6, 7, 9]")).to.deep.equal([6, 7, 9]) + expect(evaluate("[6, \"8\", 9]")).to.have.lengthOf(3) + expect(evaluate("[6, 7%2]")).to.deep.equal([6, 1]) + // Access array indices + expect(evaluate("[6, 7][1]")).to.equal(7) + expect(evaluate("[6, 7, 8, 9, 10][2*2-1]")).to.equal(9) + }) + + it("can apply functions to arrays", function() { + expect(evaluate("length [6, 7, 9]")).to.equal(3) + expect(evaluate("length [6, 7, 8, 9]")).to.equal(4) + expect(evaluate("[6, 7, 9]||[10,11,12]")).to.deep.equal([6, 7, 9, 10, 11, 12]) + expect(evaluate("6 in [6, 7, 9]")).to.be.true + expect(evaluate("2 in [6, 7, 9]")).to.be.false + expect(evaluate("min([10, 6, 7, 8, 9])")).to.equal(6) + expect(evaluate("max([6, 7, 8, 9, 2])")).to.equal(9) + }) + + it("throws errors when invalid function parameters are provided", function() { + expect(() => evaluate("max()")).to.throw() + expect(() => evaluate("min()")).to.throw() + }) + + it("parses constants", function() { + expect(evaluate("pi")).to.equal(Math.PI) + expect(evaluate("PI")).to.equal(Math.PI) + expect(evaluate("π")).to.equal(Math.PI) + expect(evaluate("e")).to.equal(Math.E) + expect(evaluate("E")).to.equal(Math.E) + expect(evaluate("true")).to.be.true + expect(evaluate("false")).to.be.false + // expect(evaluate("∞")).to.equal(Math.Infinity) + // expect(evaluate("infinity")).to.equal(Math.Infinity) + // expect(evaluate("Infinity")).to.equal(Math.Infinity) + }) + + it("can be provided variables", function() { + const u = [1, 2, 3, 4] + const x = 10 + const s_ = "string" + const f = (x) => x * 2 + expect(evaluate("u", { u })).to.deep.equal([...u]) + expect(evaluate("x", { x })).to.equal(x) + expect(evaluate("s_", { s_ })).to.equal(s_) + expect(evaluate("f", { f })).to.equal(f) + expect(evaluate("b", { b: true })).to.equal(true) + expect(evaluate("u[1]", { u })).to.equal(u[1]) + expect(evaluate("x/2", { x })).to.equal(x / 2) + expect(evaluate("f(2)", { f })).to.equal(f(2)) + expect(evaluate("if(x == f(2), u[0], s_)", { x, u, s_, f })).to.equal(s_) + }) + + it("can be provided objects", function() { + const obj = { execute: (x) => x * 3, x: 10, y: { cached: true, execute: () => 20 } } + expect(evaluate("O(3)+O(2)", { O: obj })).to.equal(9 + 6) + expect(evaluate("O.x+O.y", { O: obj })).to.equal(30) + }) + + it("throws errors when trying to use variables wrongly", function() { + const obj = { execute: (x) => x * 3 } + expect(() => evaluate("O()", { O: obj })).to.throw() + expect(() => evaluate("O.x", { O: obj })).to.throw() + expect(() => evaluate("x()", { x: 10 })).to.throw() + expect(() => evaluate("x")).to.throw() + expect(() => evaluate("n")).to.throw() + }) + + it("can do it all at once", function() { + const obj = { execute: (x) => x * 3, x: 20 } + const u = [1, 2, 3, 4] + const x = 10 + const s = "string" + const expr = "random(e) <= e ? fac(x)+u[2]+O(pi) : O.x+length s" + expect(evaluate(expr, { x, u, s, O: obj })).to.equal(3628803 + obj.execute(Math.PI)) + }) + + it("cannot parse invalid expressions", function() { + expect(() => evaluate("1+")).to.throw() + expect(() => evaluate("@")).to.throw() + expect(() => evaluate("]")).to.throw() + expect(() => evaluate("")).to.throw() + expect(() => evaluate(`"\\u35P2"`)).to.throw() + expect(() => evaluate(`"\\x"`)).to.throw() + }) + }) + + describe("#parse.toString", function() { + it("can be converted back into a string without changes", function() { + const expressions = ["pi+2*(e+2)^4", "sin(1+2!+pi+cos -3)^2", "[2,3,4][(2-1)*2]", "true ? false : true"] + for(const ogString of expressions) { + const expr = ExprEval.parse(ogString) + const convertedString = expr.toString() + expect(ExprEval.parse(convertedString)).to.deep.equal(expr) // Can be reparsed just the same + } + }) + }) + + describe("#parse.substitute", function() { + const parsed = ExprEval.parse("if(x == 0, 1, 2+x)") + it("can substitute a variable for a number", function() { + expect(parsed.substitute("x", 10).evaluate({})).to.equal(12) + expect(parsed.substitute("x", 0).evaluate({})).to.equal(1) + }) + + it("can substitute a variable for another", function() { + expect(parsed.substitute("x", "b").evaluate({ b: 10 })).to.equal(12) + expect(parsed.substitute("x", "b").evaluate({ b: 0 })).to.equal(1) + }) + + it("can substitute a variable for an expression", function() { + expect(parsed.substitute("x", "sin α").evaluate({ "α": Math.PI / 2 })).to.be.approximately(3, Number.EPSILON) + expect(parsed.substitute("x", "sin α").evaluate({ "α": 0 })).to.equal(1) + expect(parsed.substitute("x", "α == 1 ? 0 : 1").evaluate({ "α": 1 })).to.equal(1) + }) + }) + + describe("#parse.variables", function() { + it("can list all parsed undefined variables", function() { + expect(ExprEval.parse("a+b+x+pi+sin(b)").variables()).to.deep.equal(["a", "b", "x"]) + }) + }) + + describe("#parse.toJSFunction", function() { + const func = ExprEval.parse("not(false) ? a+b+x+1/x : x!+random()+A.x+[][0]").toJSFunction("x", { a: "10", b: "0" }) + expect(func(10)).to.equal(20.1) + expect(func(20)).to.equal(30.05) }) @@ -143,7 +345,7 @@ describe("Module/ExprEval", function() { describe("#derivative", function() { const DELTA = 1e-5 - it("returns the derivative value between two integers", function() { + it("returns the derivative value of a function at a given number", function() { expect(ExprEval.derivative("1", "t", 2)).to.be.approximately(0, DELTA) expect(ExprEval.derivative("t", "t", 2)).to.be.approximately(1, DELTA) expect(ExprEval.derivative("t^2", "t", 2)).to.be.approximately(4, DELTA)