parser.md (1508B)
1 <!-- Note: This file is automatically generated from source code comments. Changes made in this file will be overridden. --> 2 3 # Function parser 4 5 Create a parser. The function creates a new `math.Parser` object. 6 7 8 ## Syntax 9 10 ```js 11 math.parser() 12 ``` 13 14 ### Parameters 15 16 Parameter | Type | Description 17 --------- | ---- | ----------- 18 19 20 ### Returns 21 22 Type | Description 23 ---- | ----------- 24 Parser | Parser 25 26 27 ### Throws 28 29 Type | Description 30 ---- | ----------- 31 32 33 ## Examples 34 35 ```js 36 const parser = new math.parser() 37 38 // evaluate expressions 39 const a = parser.evaluate('sqrt(3^2 + 4^2)') // 5 40 const b = parser.evaluate('sqrt(-4)') // 2i 41 const c = parser.evaluate('2 inch in cm') // 5.08 cm 42 const d = parser.evaluate('cos(45 deg)') // 0.7071067811865476 43 44 // define variables and functions 45 parser.evaluate('x = 7 / 2') // 3.5 46 parser.evaluate('x + 3') // 6.5 47 parser.evaluate('f(x, y) = x^y') // f(x, y) 48 parser.evaluate('f(2, 3)') // 8 49 50 // get and set variables and functions 51 const x = parser.get('x') // 7 52 const f = parser.get('f') // function 53 const g = f(3, 2) // 9 54 parser.set('h', 500) 55 const i = parser.evaluate('h / 2') // 250 56 parser.set('hello', function (name) { 57 return 'hello, ' + name + '!' 58 }) 59 parser.evaluate('hello("user")') // "hello, user!" 60 61 // clear defined functions and variables 62 parser.clear() 63 ``` 64 65 66 ## See also 67 68 [evaluate](evaluate.md), 69 [compile](compile.md), 70 [parse](parse.md)